Sample records for bimodal space power

  1. Bimode uninterruptible power supply compatibility in renewable hybrid energy systems

    Energy Technology Data Exchange (ETDEWEB)

    Bower, W. (Sandia National Labs., Albuquerque, NM (USA)); O' Sullivan, G. (Abacus Controls, Inc., Somerville, NJ (USA))


    Inverters installed in renewable hybrid energy systems are typically used in a stand-alone mode to supply ac power to loads from battery storage when the engine-generator is not being used. Similarities in topology and in the performance requirements of the standby uninterruptible power supply (UPS) system and the hybrid system suggest the UPS could be used in hybrid energy systems. Another alternative to inverters with add-on charging circuits or standby UPS hardware is the Bimode UPS. The bimode UPS uses common circuitry and power components for dc to ac inversion and battery charging. It also provides an automatic and nearly instantaneous ac power transfer function when the engine-generator is started or stopped. The measured operating and transfer characteristics of a bimode UPS in a utility system and in a hybrid system are presented. The applicability of the bimode UPS to hybrid systems and its compatibility in a PV/engine-generator hybrid system are given.

  2. Integrated propulsion and power modeling for bimodal nuclear thermal rockets (United States)

    Clough, Joshua

    Bimodal nuclear thermal rocket (BNTR) engines have been shown to reduce the weight of space vehicles to the Moon, Mars, and beyond by utilizing a common reactor for propulsion and power generation. These savings lead to reduced launch vehicle costs and/or increased mission safety and capability. Experimental work of the Rover/NERVA program demonstrated the feasibility of NTR systems for trajectories to Mars. Numerous recent studies have demonstrated the economic and performance benefits of BNTR operation. Relatively little, however, is known about the reactor-level operation of a BNTR engine. The objective of this dissertation is to develop a numerical BNTR engine model in order to study the feasibility and component-level impact of utilizing a NERVA-derived reactor as a heat source for both propulsion and power. The primary contribution is to provide the first-of-its-kind model and analysis of a NERVA-derived BNTR engine. Numerical component models have been modified and created for the NERVA reactor fuel elements and tie tubes, including 1-D coolant thermodynamics and radial thermal conduction with heat generation. A BNTR engine system model has been created in order to design and analyze an engine employing an expander-cycle nuclear rocket and Brayton cycle power generator using the same reactor. Design point results show that a 316 MWt reactor produces a thrust and specific impulse of 66.6 kN and 917 s, respectively. The same reactor can be run at 73.8 kWt to produce the necessary 16.7 kW electric power with a Brayton cycle generator. This demonstrates the feasibility of BNTR operation with a NERVA-derived reactor but also indicates that the reactor control system must be able to operate with precision across a wide power range, and that the transient analysis of reactor decay heat merits future investigation. Results also identify a significant reactor pressure-drop limitation during propulsion and power-generation operation that is caused by poor tie tube

  3. Finite-thrust optimization of interplanetary transfers of space vehicle with bimodal nuclear thermal propulsion (United States)

    Kharytonov, Oleksii M.; Kiforenko, Boris M.


    The nuclear thermal rocket (NTR) propulsion is one of the leading promising technologies for primary space propulsion for manned exploration of the solar system due to its high specific impulse capability and sufficiently high thrust-to-weight ratio. Another benefit of NTR is its possible bimodal design, when nuclear reactor is used for generation of a jet thrust in a high-thrust mode and (with an appropriate power conversion system) as a source of electric power to supply the payload and the electric engines in a low-thrust mode. The model of the NTR thrust control was developed considering high-thrust NTR as a propulsion system of limited power and exhaust velocity. For the proposed model the control of the thrust value is accomplished by the regulation of reactor thermal power and propellant mass flow rate. The problem of joint optimization of the combination of high- and low-thrust arcs and the parameters of bimodal NTR (BNTR) propulsion system is considered for the interplanetary transfers. The interplanetary trajectory of the space vehicle is formed by the high-thrust NTR burns, which define planet-centric maneuvers and by the low-thrust heliocentric arcs where the nuclear electric propulsion (NEP) is used. The high-thrust arcs are analyzed using finite-thrust approach. The motion of the corresponding dynamical system is realized in three phase spaces concerning the departure planet-centric maneuver by means of high-thrust NTR propulsion, the low-thrust NEP heliocentric maneuver and the approach high-thrust NTR planet-centric maneuver. The phase coordinates are related at the time instants of the change of the phase spaces due to the relations between the space vehicle masses. The optimal control analysis is performed using Pontryagin's maximum principle. The numerical results are analyzed for Earth-Mars "sprint" transfer. The optimal values of the parameters that define the masses of NTR and NEP subsystems have been evaluated. It is shown that the low

  4. Space Solar Power Program

    Energy Technology Data Exchange (ETDEWEB)

    Arif, H.; Barbosa, H.; Bardet, C.; Baroud, M.; Behar, A.; Berrier, K.; Berthe, P.; Bertrand, R.; Bibyk, I.; Bisson, J.; Bloch, L.; Bobadilla, G.; Bourque, D.; Bush, L.; Carandang, R.; Chiku, T.; Crosby, N.; De Seixas, M.; De Vries, J.; Doll, S.; Dufour, F.; Eckart, P.; Fahey, M.; Fenot, F.; Foeckersperger, S.; Fontaine, J.E.; Fowler, R.; Frey, H.; Fujio, H.; Gasa, J.M.; Gleave, J.; Godoe, J.; Green, I.; Haeberli, R.; Hanada, T.; Ha


    Information pertaining to the Space Solar Power Program is presented on energy analysis; markets; overall development plan; organizational plan; environmental and safety issues; power systems; space transportation; space manufacturing, construction, operations; design examples; and finance.

  5. Multimegawatt space power reactors

    Energy Technology Data Exchange (ETDEWEB)

    Dearien, J.A.; Whitbeck, J.F.


    In response to the need of the Strategic Defense Initiative (SDI) and long range space exploration and extra-terrestrial basing by the National Air and Space Administration (NASA), concepts for nuclear power systems in the multi-megawatt levels are being designed and evaluated. The requirements for these power systems are being driven primarily by the need to minimize weight and maximize safety and reliability. This paper will discuss the present requirements for space based advanced power systems, technological issues associated with the development of these advanced nuclear power systems, and some of the concepts proposed for generating large amounts of power in space. 31 figs.

  6. Nuclear Power in Space (United States)


    In the early years of the United States space program, lightweight batteries, fuel cells, and solar modules provided electric power for space missions. As missions became more ambitious and complex, power needs increased and scientists investigated various options to meet these challenging power requirements. One of the options was nuclear energy. By the mid-1950s, research had begun in earnest on ways to use nuclear power in space. These efforts resulted in the first radioisotope thermoelectric generators (RTGs), which are nuclear power generators build specifically for space and special terrestrial uses. These RTGs convert the heat generated from the natural decay of their radioactive fuel into electricity. RTGs have powered many spacecraft used for exploring the outer planets of the solar system and orbiting the sun and Earth. They have also landed on Mars and the moon. They provide the power that enables us to see and learn about even the farthermost objects in our solar system.

  7. Space Propulsion and Power (United States)


    uniform dense plasmas ? Distribution A: Approved for public release; distribution is unlimited Space Propulsion and Power - New Research Areas Non ...interactions of the Matters in Space Propulsion Systems Space Propulsion and Power Portfolio Coupled Materials and Plasma Processes Far From...primary electron  1 • Effective secondary electron emission * accounts for non - Maxwellian effects * > 1 * < 1 ~4 MHz Sheath Beams of SEE

  8. Space Nuclear Power Systems (United States)

    Houts, Michael G.


    Fission power and propulsion systems can enable exciting space exploration missions. These include bases on the moon and Mars; and the exploration, development, and utilization of the solar system. In the near-term, fission surface power systems could provide abundant, constant, cost-effective power anywhere on the surface of the Moon or Mars, independent of available sunlight. Affordable access to Mars, the asteroid belt, or other destinations could be provided by nuclear thermal rockets. In the further term, high performance fission power supplies could enable both extremely high power levels on planetary surfaces and fission electric propulsion vehicles for rapid, efficient cargo and crew transfer. Advanced fission propulsion systems could eventually allow routine access to the entire solar system. Fission systems could also enable the utilization of resources within the solar system.

  9. Space power systems technology (United States)

    Coulman, George A.


    Reported here is a series of studies which examine several potential catalysts and electrodes for some fuel cell systems, some materials for space applications, and mathematical modeling and performance predictions for some solid oxide fuel cells and electrolyzers. The fuel cell systems have a potential for terrestrial applications in addition to solar energy conversion in space applications. Catalysts and electrodes for phosphoric acid fuel cell systems and for polymer electrolyte membrane (PEM) fuel cell and electrolyzer systems were examined.

  10. Power systems for space exploration (United States)

    Shipbaugh, Calvin; Solomon, Kenneth A.

    The Outreach Program was designed to solicit creative ideas from academia, research institutions, private enterprises, and the general public and is intended to be helpful in defining promising technical areas and program paths for more detailed study. To the Outreach Program, a number of power system concepts were proposed. In conclusion, there are a number of advanced concepts for space power and propulsion sources that deserve study if we want to expand our ability to not only explore space, but to utilize it. Advanced nuclear concepts and power beaming concepts are two areas worthy of detailed assessments.

  11. Space Solar Power Program. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Arif, Humayun; Barbosa, Hugo; Bardet, Christophe; Baroud, Michel; Behar, Alberto; Berrier, Keith; Berthe, Phillipe; Bertrand, Reinhold; Bibyk, Irene; Bisson, Joel; Bloch, Lawrence; Bobadilla, Gabriel; Bourque, Denis; Bush, Lawrence; Carandang, Romeo; Chiku, Takemi; Crosby, Norma; De Seixas, Manuel; De Vries, Joha; Doll, Susan; Dufour, Francois; Eckart, Peter; Fahey, Michael; Fenot, Frederic; Foeckersperger, Stefan; Fontaine, Jean-Emmanuel; Fowler, Robert; Frey, Harald; Fujio, Hironobu; Gasa, Jaume Munich; Gleave, Janet; Godoe, Jostein; Green, Iain; Haeberli, Roman; Hanada, Toshiya; Harris, Peter; Hucteau, Mario; Jacobs, Didier Fernand; Johnson, Richard; Kanno, Yoshitsugu; Koenig, Eva Maria; Kojima, Kazuo; Kondepudi, Phani; Kottbauer, Christian; Kulper, Doede; Kulagin, Konstantin; Kumara, Pekka; Kurz, Rainer; Laaksonen, Jyrki; Lang, Andrew Neill; Lathan, Corinna; Le Fur, Thierry; Lewis, David; Louis, Alain; Mori, Takeshi; Morlanes, Juan; Murbach, Marcus; Nagatomo, Hideo; O' brien, Ivan; Paines, Justin; Palaszewski, Bryan; Palmnaes, Ulf; Paraschivolu, Marius; Pathare, Asmin; Perov, Egor; Persson, Jan; Pessoa-Lopes, Isabel; Pinto, Michel; Porro, Irene; Reichert, Michael; Ritt-Fischer, Monika; Roberts, Margaret; Robertson II, Lawrence; Rogers, Keith; Sasaki, Tetsuo; Scire, Francesca; Shibatou, Katsuya; Shirai, Tatsuya; Shiraishi, Atsushi; Soucaille, Jean-Francois; Spivack, Nova; St. Pierre, Dany; Suleman, Afzal; Sullivan, Thomas; Theelen, Bas Johan; Thonstad, Hallvard; Tsuji, Masatoshi; Uchiumi, Masaharu; Vidqvist, Jouni; Warrell, David; Watanabe, Takafumi; Willis, Richard; Wolf, Frank; Yamakawa, Hiroshi; Zhao, Hong


    Information pertaining to the Space Solar Power Program is presented on energy analysis; markets; overall development plan; organizational plan; environmental and safety issues; power systems; space transportation; space manufacturing, construction, operations; design examples; and finance.

  12. Thermoelectric power conversion in space (United States)

    Awaya, Henry I.; Ewell, Richard; Nesmith, Bill; Vandersande, James


    A radiatively-heated multicouple for use in the next generation of radioisotope thermoelectric generator (RTG) will employ 20 individual couples within a single cell, so that 40 n- and p-semiconductor legs will be interconnected in series. At the hot end of the RTG, the legs will be electrically interconnected using silicon molybdenum; on the cold side, the legs are interconnected by tungsten. The entire cell is then mechanically attached to a radiator, which conducts heat away and radiates it into space. Deep-space applications will use RTGs developed for vacuum operation; thermoelectric converter power systems using a unicouple configuration have flown on such missions as Pioneers 10 and 11, which used lead telluride thermoelectric converters, and Voyagers I and II, which used silicon germanium-based thermoelectrics.

  13. Space power technology 21: Photovoltaics (United States)

    Wise, Joseph


    The Space Power needs for the 21st Century and the program in photovoltaics needed to achieve it are discussed. Workshops were conducted in eight different power disciplines involving industry and other government agencies. The Photovoltaics Workshop was conducted at Aerospace Corporation in June 1987. The major findings and recommended program from this workshop are discussed. The major finding is that a survivable solar power capability is needed in photovoltaics for critical Department of Defense missions including Air Force and Strategic Defense Initiative. The tasks needed to realize this capability are described in technical, not financial, terms. The second finding is the need for lightweight, moderately survivable planar solar arrays. High efficiency thin III-V solar cells can meet some of these requirements. Higher efficiency, longer life solar cells are needed for application to both future planar and concentrator arrays with usable life up to 10 years. Increasing threats are also anticipated and means for avoiding prolonged exposure, retraction, maneuvering and autonomous operation are discussed.

  14. Space power technology 21: Photovoltaics (United States)

    Wise, Joseph


    The Space Power needs for the 21st Century and the program in photovoltaics needed to achieve it are discussed. Workshops were conducted in eight different power disciplines involving industry and other government agencies. The Photovoltaics Workshop was conducted at Aerospace Corporation in June 1987. The major findings and recommended program from this workshop are discussed. The major finding is that a survivable solar power capability is needed in photovoltaics for critical Department of Defense missions including Air Force and Strategic Defense Initiative. The tasks needed to realize this capability are described in technical, not financial, terms. The second finding is the need for lightweight, moderately survivable planar solar arrays. High efficiency thin III-V solar cells can meet some of these requirements. Higher efficiency, longer life solar cells are needed for application to both future planar and concentrator arrays with usable life up to 10 years. Increasing threats are also anticipated and means for avoiding prolonged exposure, retraction, maneuvering and autonomous operation are discussed.

  15. A hybrid approach to space power control (United States)

    Gholdston, E. W.; Janik, D. F.; Newton, K. A.


    Conventional control systems have traditionally been utilized for space-based power designs. However, the use of expert systems is becoming important for NASA applications. Rocketdyne has been pursuing the development of expert systems to aid and enhance control designs of space-based power systems. The need for integrated expert systems is vital for the development of autonomous power systems.

  16. Atomic Power in Space: A History (United States)


    "Atomic Power in Space," a history of the Space Isotope Power Program of the United States, covers the period from the program's inception in the mid-1950s through 1982. Written in non-technical language, the history is addressed to both the general public and those more specialized in nuclear and space technologies. Interplanetary space exploration successes and achievements have been made possible by this technology, for which there is no known substitue.

  17. Space commercialization and power system technology (United States)

    Brandhorst, H., Jr.; Faymon, K. A.


    The development and application of power and energy technologies important to the commercialization of space is discussed, stressing the significance of these technologies to space transportation systems, on-orbit services and on-orbit commercial production and processing ventures. Energy conversion systems examined include solar photovoltaic systems, solar thermal dynamic power systems, and nuclear power systems. Energy storage systems include electrochemical systems, inertial storage systems, and magnetic energy storage systems. In addition, power management and distribution systems used in space commercialization and NASA programs for the commercial development of space are discussed.

  18. A power beaming based infrastructure for space power

    Energy Technology Data Exchange (ETDEWEB)

    Bamberger, J.A.


    At present all space mission power requirements are met by integral, on-board, self-contained power systems. To provide needed flexibility for space exploration and colonization, an additional approach to on-board, self-contained power systems is needed. Power beaming, an alternative approach to providing power, has the potential to provide increased mission flexibility while reducing total mass launched into space. Laser-power beaming technology provides a viable power and communication infrastructure that can be developed sequentially as it is applied to power satellite constellations in Earth orbit and to orbital transport vehicles transferring satellites and cargos to geosynchronous orbit and beyond. Coupled with nuclear electric propulsion systems for cargo transport, the technology can be used to provide global power to the Lunar surface and to Mars' surface and moons. The technology can be developed sequentially as advances in power system and propulsion system technology occur. This paper presents stepwise development of an infrastructure based on power beaming that can support the space development and exploration goals of the Space Exploration Initiative. Power scenarios based on commonality of power systems hardware with cargo transport vehicles are described. Advantages of this infrastructure are described. 12 refs., 4 figs., 1 tab.

  19. Emerging US Space Launch, Trends and Space Solar Power (United States)

    Zapata, Edgar


    Reviews the state of the art of emerging US space launch and spacecraft. Reviews the NASA budget ascontext, while providing example scenarios. Connects what has been learned in space systems commercial partnershipsto a potential path for consideration by the space solar power community.

  20. Space nuclear power: a strategy for tomorrow

    Energy Technology Data Exchange (ETDEWEB)

    Buden, D.; Angelo, J. Jr.


    Energy: reliable, portable, abundant and low cost will be a most critical factor, perhaps the sine qua non, for the unfolding of man's permanent presence in space. Space-based nuclear power, in turn, is a key technology for developing such space platforms and the transportation systems necessary to service them. A strategy for meeting space power requirements is the development of a 100-kW(e) nuclear reactor system for high earth orbit missions, transportation from Shuttle orbits to geosynchronous orbit, and for outer planet exploration. The component technology for this nuclear power plant is now underway at the Los Alamos National Laboratory. As permanent settlements are established on the Moon and in space, multimegawatt power plants will be needed. This would involve different technology similar to terrestrial nuclear power plants.

  1. Atomic power in space: A history

    Energy Technology Data Exchange (ETDEWEB)


    ''Atomic Power in Space,'' a history of the Space Isotope Power Program of the United States, covers the period from the program's inception in the mid-1950s through 1982. Written in non-technical language, the history is addressed to both the general public and those more specialized in nuclear and space technologies. 19 figs., 3 tabs.

  2. Modular Power Standard for Space Explorations Missions (United States)

    Oeftering, Richard C.; Gardner, Brent G.


    Future human space exploration will most likely be composed of assemblies of multiple modular spacecraft elements with interconnected electrical power systems. An electrical system composed of a standardized set modular building blocks provides significant development, integration, and operational cost advantages. The modular approach can also provide the flexibility to configure power systems to meet the mission needs. A primary goal of the Advanced Exploration Systems (AES) Modular Power System (AMPS) project is to establish a Modular Power Standard that is needed to realize these benefits. This paper is intended to give the space exploration community a "first look" at the evolving Modular Power Standard and invite their comments and technical contributions.

  3. Key issues in space nuclear power (United States)

    Brandhorst, Henry W.


    The future appears rich in missions that will extend the frontiers of knowledge, human presence in space, and opportunities for profitable commerce. Key to the success of these ventures is the availability of plentiful, cost effective electric power and assured, low cost access to space. While forecasts of space power needs are problematic, an assessment of future needs based on terrestrial experience has been made. These needs fall into three broad categories: survival, self sufficiency, and industrialization. The cost of delivering payloads to orbital locations from LEO to Mars has been determined and future launch cost reductions projected. From these factors, then, projections of the performance necessary for future solar and nuclear space power options has been made. These goals are largely dependent upon orbital location and energy storage needs. Finally the cost of present space power systems has been determined and projections made for future systems.

  4. Irreducible complexity of iterated symmetric bimodal maps

    Directory of Open Access Journals (Sweden)

    J. P. Lampreia


    Full Text Available We introduce a tree structure for the iterates of symmetric bimodal maps and identify a subset which we prove to be isomorphic to the family of unimodal maps. This subset is used as a second factor for a ∗-product that we define in the space of bimodal kneading sequences. Finally, we give some properties for this product and study the ∗-product induced on the associated Markov shifts.

  5. Demonstration of microwave power transmission in space (United States)

    Chang, K.; Patton, A. D.; Kennedy, M. O.; Little, F. E.; Pollock, M. A.; Hummer, K. A.; Mccleary, J. C.; Wei, B. S.; Brown, A. M.; Mcspadden, J.O.


    Three experiments are proposed to demonstrate the feasibility of converting dc power into microwave or millimeter-wave beam and transmitting it to users through free space. The generator could be located on earth or on a utility power satellite. The received power would be converted back into dc or ac power. The success of the experiments could lead to the commercial use of this technology.

  6. Future Photovoltaic Power Generation for Space-Based Power Utilities (United States)

    Bailey, S.; Landis, G.; Raffaelle, R.; Hepp, A.


    A recent NASA program, Space Solar Power Exploratory Research and Technology (SERT), investigated the technologies needed to provide cost-competitive ground baseload electrical power from space based solar energy conversion. This goal mandated low cost, light weight gigawatt (GW) power generation. Investment in solar power generation technologies would also benefit high power military, commercial and science missions. These missions are generally those involving solar electric propulsion, surface power systems to sustain an outpost or a permanent colony on the surface of the moon or mars, space based lasers or radar, or as large earth orbiting power stations which can serve as central utilities for other orbiting spacecraft, or as in the SERT program, potentially beaming power to the earth itself. This paper will discuss requirements for the two latter options, the current state of the art of space solar cells, and a variety of both evolving thin film cells as well as new technologies which may impact the future choice of space solar cells for a high power mission application. The space world has primarily transitioned to commercially available III-V (GaInP/GaAs/Ge) cells with 24-26% air mass zero (AMO) efficiencies. Research in the III-V multi-junction solar cells has focused on fabricating either lattice-mismatched materials with optimum stacking bandgaps or new lattice matched materials with optimum bandgaps. In the near term this will yield a 30% commercially available space cell and in the far term possibly a 40% cell. Cost reduction would be achieved if these cells could be grown on a silicon rather than a germanium substrate since the substrate is ~65% of the cell cost or, better yet, on a polyimide or possibly a ceramic substrate. An overview of multi-junction cell characteristics will be presented here. Thin film cells require substantially less material and have promised the advantage of large area, low cost manufacturing. However, space cell requirements

  7. Rendevous in Space: Looking in on Military Space Power (United States)


    independent ser - vice.11 Although space power discussion today parallels those of air power prior to WWII, the arguments that arise about the employment...the Mitchell persona – may have fueled the grassroots culture among pilots and those who belonged to the U.S. Army Air Corps. Deeper inside the

  8. Adaptive Power Control for Space Communications (United States)

    Thompson, Willie L., II; Israel, David J.


    This paper investigates the implementation of power control techniques for crosslinks communications during a rendezvous scenario of the Crew Exploration Vehicle (CEV) and the Lunar Surface Access Module (LSAM). During the rendezvous, NASA requires that the CEV supports two communication links: space-to-ground and crosslink simultaneously. The crosslink will generate excess interference to the space-to-ground link as the distances between the two vehicles decreases, if the output power is fixed and optimized for the worst-case link analysis at the maximum distance range. As a result, power control is required to maintain the optimal power level for the crosslink without interfering with the space-to-ground link. A proof-of-concept will be described and implemented with Goddard Space Flight Center (GSFC) Communications, Standard, and Technology Lab (CSTL).

  9. Deep Space Cryogenic Power Electronics Project (United States)

    National Aeronautics and Space Administration — Technology Application, Inc. (TAI) is proposing to demonstrate feasibility of implementing silicon germanium (SiGe) strained-gate technology in the power...

  10. New directions for space solar power (United States)

    Mankins, John C.


    Several of the central issues associated with the eventual realization of the vision of solar power from space for terrestrial markets resolve around the expect costs associated with the assembly, inspection, maintenance and repair of future solar power satellite (SPS) stations. In past studies (for example, NASA's "Fresh Look Study", c. 1995-1997) efforts were made to reduce both the scale and mass of large, systems-level interfaces (e.g., the power management and distribution (PMAD) system) and on-orbit fixed infrastructures through the use of modular systems strategies. These efforts have had mixed success (as reflected in the projected on-orbit mass of various systems concepts. However, the author remains convinced of the importance of modular strategies for exceptionally large space systems in eventually realizing the vision of power from space. This paper will introduce some of the key issues associated with cost-competitive space solar power in terrestrial markets. It will examine some of the relevant SPS concepts and will assess the 'pros and cons' of each in terms of space assembly, maintenance and servicing (SAMS) requirements. The paper discusses at a high level some relevant concepts and technologies that may play r role in the eventual, successful resolution of these challenges. The paper concludes with an example of the kind of novel architectural approach for space solar power that is needed.

  11. The NASA space power technology program (United States)

    Stephenson, R. Rhoads

    NASA has a broad technology program in the field of space power. This paper describes that program, including the roles and responsibilities of the various NASA field centers and major contractors. In the power source area, the paper discusses the SP-100 Space Nuclear Power Project, which has been under way for about seven years and is making substantial progress toward development of components for a 100-kilowatt power system that can be scaled to other sizes. This system is a candidate power source for nuclear electric propulsion, as well as for a power plant for a lunar base. In the energy storage area, the paper describes NASA's battery- and fuel-cell development programs. NASA is actively working on NiCd, NiH2, and lithium batteries. A status update is also given on a U.S. Air Force-sponsored program to develop a large (150 ampere-hour) lithium-thionyl chloride battery for the Centaur upper-stage launch vehicle. Finally, the area of power management and distribution (PMAD) is addressed, including power system components such as solid-state switches and power integrated circuits. Automated load management and other computer-controlled functions offer considerable payoffs. The state of the art in space power is described, along with NASA's medium- and long-term goals in the area.

  12. Millimeterwave Space Power Grid architecture development 2012 (United States)

    Komerath, Narayanan; Dessanti, Brendan; Shah, Shaan

    This is an update of the Space Power Grid architecture for space-based solar power with an improved design of the collector/converter link, the primary heater and the radiator of the active thermal control system. The Space Power Grid offers an evolutionary approach towards TeraWatt-level Space-based solar power. The use of millimeter wave frequencies (around 220GHz) and Low-Mid Earth Orbits shrinks the size of the space and ground infrastructure to manageable levels. In prior work we showed that using Brayton cycle conversion of solar power allows large economies of scale compared to the linear mass-power relationship of photovoltaic conversion. With high-temperature materials permitting 3600 K temperature in the primary heater, over 80 percent cycle efficiency was shown with a closed helium cycle for the 1GW converter satellite which formed the core element of the architecture. Work done since the last IEEE conference has shown that the use of waveguides incorporated into lighter-than-air antenna platforms, can overcome the difficulties in transmitting millimeter wave power through the moist, dense lower atmosphere. A graphene-based radiator design conservatively meets the mass budget for the waste heat rejection system needed for the compressor inlet temperature. Placing the ultralight Mirasol collectors in lower orbits overcomes the solar beam spot size problem of high-orbit collection. The architecture begins by establishing a power exchange with terrestrial renewable energy plants, creating an early revenue generation approach with low investment. The approach allows for technology development and demonstration of high power millimeter wave technology. A multinational experiment using the International Space Station and another power exchange satellite is proposed to gather required data and experience, thus reducing the technical and policy risks. The full-scale architecture deploys pairs of Mirasol sunlight collectors and Girasol 1 GW converter satellites t

  13. Wireless Power Transfer in 3D Space

    Directory of Open Access Journals (Sweden)



    Full Text Available The main objective of this project is to develop a system of wireless power transfer in 3D space. This concept based on low frequency to high frequency conversion. High frequency power is transmit between air-core and inductor. This work presents an experiment for wireless energy transfer by using the Inductive resonant coupling (also known as resonant energy transfer phenomenon. The basic principles will be presented about this physical phenomenon, the experiment design, and the results obtained for the measurements performed on the system. The parameters measured were the efficiency of the power transfer, and the angle between emitter and receiver. We can achieve wireless power transfer up to 10watts in 3D space using high frequency through tuned circuit. The wireless power supply is motivated by simple and comfortable use of many small electric appliances with low power input.

  14. Space Power for Communication Satellites Beyond 1995 (United States)

    Pierce, P. R.


    The space power trends for communication satellites beginning in the mid-70's are reviewed. Predictions of technology advancements and requirements were compared with actual growth patterns. The conclusions derived suggest that the spacecraft power system technology base and present rate of advancement will not be able to meet the power demands of the early to mid-90's. It is recommended that an emphasis on accelerating the technology development be made to minimize the technology gap.

  15. Power electronic applications for Space Station Freedom (United States)

    Pickrell, Roy L.; Lazbin, Igor


    NASA plans to orbit a permanently manned space station in the late 1990s, which requires development and assembly of a photovoltaic (PV) power source system to supply up to 75 kW of electrical power average during the orbital period. The electrical power requirements are to be met by a combination of PV source, storage, and control elements for the sun and eclipse periods. The authors discuss the application of power electronics and controls to manage the generation, storage, and distribution of power to meet the station loads, as well as the computer models used for analysis and simulation of the PV power system. The requirements for power source integrated controls to adjust storage charge power during the insolation period current limiting, breaker interrupt current values, and the electrical fault protection approach are defined. Based on these requirements, operating concepts have been defined which then become drivers for specific system and element design.

  16. Advanced materials for space nuclear power systems (United States)

    Titran, Robert H.; Grobstein, Toni L.; Ellis, David L.


    The overall philosophy of the research was to develop and characterize new high temperature power conversion and radiator materials and to provide spacecraft designers with material selection options and design information. Research on three candidate materials (carbide strengthened niobium alloy PWC-11 for fuel cladding, graphite fiber reinforced copper matrix composites for heat rejection fins, and tungsten fiber reinforced niobium matrix composites for fuel containment and structural supports) considered for space power system applications is discussed. Each of these types of materials offers unique advantages for space power applications.

  17. Thermionic reactors for space nuclear power (United States)

    Griaznov, Georgii M.; Zhabotinskii, Evgenii E.; Serbin, Victor I.; Zrodnikov, Anatolii V.; Pupko, Victor Ia.; Ponomarev-Stepnoi, Nikolai N.; Usov, V. A.; Nikolaev, Iu. V.

    Compact thermionic nuclear reactor systems with satisfactory mass performance are competitive with space nuclear power systems based on the organic Rankine and closed Brayton cycles. The mass characteristics of the thermionic space nuclear power system are better than that of the solar power system for power levels beyond about 10 kWe. Longlife thermionic fuel element requirements, including their optimal dimensions, and common requirements for the in-core thermionic reactor design are formulated. Thermal and fast in-core thermionic reactors are considered and the ranges of their sensible use are discussed. Some design features of the fast in-core thermionic reactors cores (power range to 1 MWe) including a choice of coolants are discussed. Mass and dimensional performance for thermionic nuclear power reactor system are assessed. It is concluded that thermionic space nuclear power systems are promising power supplies for spacecrafts and that a single basic type of thermionic fuel element may be used for power requirements ranging to several hundred kWe.

  18. Challenges for future space power systems (United States)

    Brandhorst, Henry W., Jr.


    The future appears rich in missions that will extend the frontiers of knowledge, human presence in space, and opportunities for profitable commerce. The key to success of these ventures is the availability of plentiful, cost effective electric power and assured, low cost access to space. While forecasts of space power needs are problematic, an assessment of future needs based on terrestrial experience was made. These needs fall into three broad categories-survival, self sufficiency and industrialization. The cost of delivering payloads to orbital locations from low earth orbit (LEO) to Mars was determined and future launch cost reductions projected. From these factors, then, projections of the performance necessary for future solar and nuclear space power options were made. These goals are largely dependent upon orbital location and energy storage needs.

  19. Test report on the Abacus 30 kW bimode(reg sign) inverter and Maximum Power Tracker (MPT) (United States)

    Bonn, Russell; Ginn, Jerry; Zirzow, Jeff; Sittler, Greg


    Sandia National Laboratories conducts the photovoltaic balance of systems (BOS) program, which is sponsored by the US Department of Energy's Office of Energy Management. Under this program, SNL lets commercialization contracts and conducts a laboratory program designed to advance BOS technology, improve BOS component reliability, and reduce the BOS life-cycle-cost. This report details the testing of the first large US manufactured hybrid inverter and its associated maximum power tracker.

  20. Test report on the Abacus 30 kW bimode{reg_sign} inverter and maximum power tracker (MPT)

    Energy Technology Data Exchange (ETDEWEB)

    Bonn, R.; Ginn, J.; Zirzow, J. [and others


    Sandia National Laboratories conducts the photovoltaic balance of systems (BOS) program, which is sponsored by the US Department of Energy`s Office of Energy Management. Under this program, SNL lets commercialization contracts and conducts a laboratory program designed to advance BOS technology, improve BOS component reliability, and reduce the BOS life-cycle-cost. This report details the testing of the first large US manufactured hybrid inverter and its associated maximum power tracker.

  1. Space Shuttle Orbiter auxiliary power unit status (United States)

    Reck, M.; Loken, G.; Horton, J.; Lukens, W.; Scott, W.; Baughman, J.; Bauch, T.

    An overview of the United States Space Shuttle Orbiter APU, which provides power to the Orbiter vehicle hydraulic system, is presented. Three complete APU systems, each with its own separate fuel system, supply power to three dedicated hydraulic systems. These in turn provide power to all Orbiter vehicle critical flight functions including launch, orbit, reentry, and landing. The basic APU logic diagram is presented. The APU includes a hydrazine-powered turbine that drives a hydraulic pump and various accessories through a high-speed gearbox. The APU also features a sophisticated thermal management system designed to ensure safe and reliable operation in the various launch, orbit, reentry, and landing environments.

  2. Wireless Power Transmission Options for Space Solar Power (United States)

    Potter, Seth; Davis, Dean; Born, Martin; Bayer, Martin; Howell, Joe; Mankins, John


    Space Solar Power (SSP), combined with Wireless Power Transmission (WPT), offers the far-term potential to solve major energy problems on Earth. In the long term, we aspire to beam energy to Earth from geostationary Earth orbit (GEO), or even further distances in space. In the near term, we can beam power over more moderate distances, but still stretch the limits of today s technology. In recent studies, a 100 kWe-class "Power Plug" Satellite and a 10 kWe-class Lunar Polar Solar Power outpost have been considered as the first steps in using these WPT options for SSP. Our current assessments include consideration of orbits, wavelengths, and structural designs to meet commercial, civilian government, and military needs. Notional transmitter and receiver sizes are considered for use in supplying 5 to 40 MW of power. In the longer term, lunar or asteroidal material can be used. By using SSP and WPT technology for near-term missions, we gain experience needed for sound decisions in designing and developing larger systems to send power from space to Earth.

  3. Space Solar Power Demonstrations: Challenges and Progress (United States)

    Howell, Joe T.; Mankins, John C.; Lavoie, Anthony R. (Technical Monitor)


    The prospects of using electrical power beamed from space are coming closer to reality with the continued pursuit and improvements in the supporting space solar research and technology. Space Solar Power (SSP) has been explored off and on for approximately three decades as a viable alternative and clean energy source. Results produced through the more recent Space Solar Power Exploratory Research and Technology (SERT) program involving extensive participation by industry, universities, and government has provided a sound technical basis for believing that technology can be improved to the extent that SSP systems can be built, economically feasible, and successfully deployed in space. Considerable advancements have been made in conceptual designs and supporting technologies including solar power generation, wireless power transmission, power management distribution, thermal management and materials, and the integrated systems engineering assessments. Basic technologies have progressed to the point were the next logical step is to formulate and conduct sophisticated demonstrations involving prototype hardware as final proof of concepts and identify high end technology readiness levels in preparation for full scale SSP systems designs. In addition to continued technical development issues, environmental and safety issues must be addressed and appropriate actions taken to reassure the public and prepare them for the future use of this alternative renewable energy resource. Accomplishing these objectives will allow informed future decisions regarding further SSP and related R&D investments by both NASA management and prospective external partners. In particular, accomplishing these objectives will also guide further definition of SSP and related technology roadmaps including performance objectives, resources and schedules; including 'multi-purpose' applications (terrestrial markets, science, commercial development of space, and other government missions).

  4. Growing the Space Station's electrical power plant (United States)

    Sundberg, Gale R.

    For over a decade NASA LeRC has been defining, demonstrating, and evaluating power electronic components and multi-kilowatt, multiply redundant, electrical power systems as part of OAST charter. Whether one considers aircraft (commercial transport/military), Space Station Freedom, growth station, launch vehicles, or the new Human Exploration Initiative, the conclusions remain the same: high frequency AC power distribution and control is superior to all other approaches for achieving a fast, smart, safe, versatile, and growable electrical power system that will meet a wide range of mission options. To meet the cost and operability goals of future aerospace missions that require significantly higher electrical power and longer durations, we must learn to integrate multiple technologies in ways that enhance overall system synergisms. The way NASA is doing business in space electric power is challenged and some approaches for evolving large space vehicles and platforms in well constructed steps to provide safe, ground testable, growable, smart systems that provide simple, replicative logic structures, which enable hardware and software verification, validation, and implementation are proposed. Viewgraphs are included.

  5. The NASA Advanced Space Power Systems Project (United States)

    Mercer, Carolyn R.; Hoberecht, Mark A.; Bennett, William R.; Lvovich, Vadim F.; Bugga, Ratnakumar


    The goal of the NASA Advanced Space Power Systems Project is to develop advanced, game changing technologies that will provide future NASA space exploration missions with safe, reliable, light weight and compact power generation and energy storage systems. The development effort is focused on maturing the technologies from a technology readiness level of approximately 23 to approximately 56 as defined in the NASA Procedural Requirement 7123.1B. Currently, the project is working on two critical technology areas: High specific energy batteries, and regenerative fuel cell systems with passive fluid management. Examples of target applications for these technologies are: extending the duration of extravehicular activities (EVA) with high specific energy and energy density batteries; providing reliable, long-life power for rovers with passive fuel cell and regenerative fuel cell systems that enable reduced system complexity. Recent results from the high energy battery and regenerative fuel cell technology development efforts will be presented. The technical approach, the key performance parameters and the technical results achieved to date in each of these new elements will be included. The Advanced Space Power Systems Project is part of the Game Changing Development Program under NASAs Space Technology Mission Directorate.

  6. Small high cooling power space cooler

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, T. V.; Raab, J.; Durand, D.; Tward, E. [Northrop Grumman Aerospace Systems Redondo Beach, Ca, 90278 (United States)


    The small High Efficiency pulse tube Cooler (HEC) cooler, that has been produced and flown on a number of space infrared instruments, was originally designed to provide cooling of 10 W @ 95 K. It achieved its goal with >50% margin when limited by the 180 W output ac power of its flight electronics. It has also been produced in 2 stage configurations, typically for simultaneously cooling of focal planes to temperatures as low as 35 K and optics at higher temperatures. The need for even higher cooling power in such a low mass cryocooler is motivated by the advent of large focal plane arrays. With the current availability at NGAS of much larger power cryocooler flight electronics, reliable long term operation in space with much larger cooling powers is now possible with the flight proven 4 kg HEC mechanical cooler. Even though the single stage cooler design can be re-qualified for those larger input powers without design change, we redesigned both the linear and coaxial version passive pulse tube cold heads to re-optimize them for high power cooling at temperatures above 130 K while rejecting heat to 300 K. Small changes to the regenerator packing, the re-optimization of the tuned inertance and no change to the compressor resulted in the increased performance at 150 K. The cooler operating at 290 W input power achieves 35 W@ 150 K corresponding to a specific cooling power at 150 K of 8.25 W/W and a very high specific power of 72.5 W/Kg. At these powers the cooler still maintains large stroke, thermal and current margins. In this paper we will present the measured data and the changes to this flight proven cooler that were made to achieve this increased performance.

  7. Solar Power Beaming: From Space to Earth

    Energy Technology Data Exchange (ETDEWEB)

    Rubenchik, A M; Parker, J M; Beach, R J; Yamamoto, R M


    Harvesting solar energy in space and power beaming the collected energy to a receiver station on Earth is a very attractive way to help solve mankind's current energy and environmental problems. However, the colossal and expensive 'first step' required in achieving this goal has to-date stifled its initiation. In this paper, we will demonstrate that recent advance advances in laser and optical technology now make it possible to deploy a space-based system capable of delivering 1 MW of energy to a terrestrial receiver station, via a single unmanned commercial launch into Low Earth Orbit (LEO). Figure 1 depicts the overall concept of our solar power beaming system, showing a large solar collector in space, beaming a coherent laser beam to a receiving station on Earth. We will describe all major subsystems and provide technical and economic discussion to support our conclusions.

  8. Space Power Integration: Perspectives from Space Weapons Officers (United States)


    augment the Falconer AOCs, when required. JWS personnel will not be liaisons; they will be working for the JFACC. One critique of the current JWS...Space Power in Joint Operations,” 3. 30. Gen Richard B. Myers , National Military Strategy of the United States of America, 2004, 18. The numbers 1-4-2...Plan, 23. 48. MSgt Julie Briggs , “Near Space Enhances Joint Warfighting,” Air Force Print News, 18 February 2005,

  9. Energy storage options for space power (United States)

    Hoffman, H. W.; Martin, J. F.; Olszewski, M.

    Including energy storage in a space power supply enhances the feasibility of using thermal power cycles (Rankine or Brayton) and providing high-power pulses. Superconducting magnets, capacitors, electrochemical batteries, thermal phase-change materials (PCM), and flywheels are assessed; the results obtained suggest that flywheels and phase-change devices hold the most promise. Latent heat storage using inorganic salts and metallic eutectics offers thermal energy storage densities of 1500 kJ/kg to 2000 kJ/kg at temperatures to 1675 K. Innovative techniques allow these media to operate in direct contact with the heat engine working fluid. Enhancing thermal conductivity and/or modifying PCM crystallization habit provide other options. Flywheels of low-strain graphite and Kevlar fibers have achieved mechanical energy storage densities of 300 kJ/kg. With high-strain graphite fibers, storage densities appropriate to space power needs (about 500 kJ/kg) seem feasible. Coupling advanced flywheels with emerging high power density homopolar generators and compulsators could result in electric pulse-power storage modules of significantly higher energy density.

  10. Nuclear Power Sources for Space Systems (United States)

    Kukharkin, N. E.; Ponomarev-Stepnoi, N. N.; Usov, V. A.

    This chapter contains the information about nuclear power sources for space systems. Reactor nuclear sources are considered that use the energy of heavy nuclei fission generated by controlled chain fission reaction, as well as the isotope ones producing heat due to the energy of nuclei radioactive decay. Power of reactor nuclear sources is determined by the rate of heavy nuclei fission that may be controlled within a wide range from the zero up to the nominal one. Thermal power of isotope sources cannot be controlled. It is determined by the type and quantity of isotopes and decreases in time due to their radioactive decay. Both, in the reactor sources and in the isotope ones, nuclear power is converted into the thermal one that may be consumed for the coolant heating to produce thrust (Nuclear Power Propulsion System, NPPS) or may be converted into electricity (Nuclear Power Source, NPS) dynamically (a turbine generator) or statically (thermoelectric or thermionic converters). Electric power is supplied to the airborne equipment or is used to produce thrust in electric (ionic, plasma) low-thrust engines. A brief description is presented of the different nuclear systems with reactor and isotopic power sources implemented in Russia and the USA. The information is also given about isotopic sources for the ground-based application, mainly for navigation systems.

  11. Wireless Power Transfer for Space Applications (United States)

    Ramos, Gabriel Vazquez; Yuan, Jiann-Shiun


    This paper introduces an implementation for magnetic resonance wireless power transfer for space applications. The analysis includes an equivalent impedance study, loop material characterization, source/load resonance coupling technique, and system response behavior due to loads variability. System characterization is accomplished by executing circuit design from analytical equations and simulations using Matlab and SPICE. The theory was validated by a combination of different experiments that includes loop material consideration, resonance coupling circuits considerations, electric loads considerations and a small scale proof-of-concept prototype. Experiment results shows successful wireless power transfer for all the cases studied. The prototype provided about 4.5 W of power to the load at a separation of -5 cm from the source using a power amplifier rated for 7 W.

  12. Measuring Voting Power in Convex Policy Spaces

    Directory of Open Access Journals (Sweden)

    Sascha Kurz


    Full Text Available Classical power index analysis considers the individual’s ability to influence the aggregated group decision by changing its own vote, where all decisions and votes are assumed to be binary. In many practical applications we have more options than either “yes” or “no”. Here we generalize three important power indices to continuous convex policy spaces. This allows the analysis of a collection of economic problems like, e.g., tax rates or spending that otherwise would not be covered in binary models.

  13. Space Station Freedom secondary power wiring requirements (United States)

    Sawyer, C. R.


    Secondary power is produced by DDCU's (direct current to direct current converter units) and routed to and through secondary power distribution assemblies (SPDA's) to loads or tertiary distribution assemblies. This presentation outlines requirements of Space Station Freedom (SSF) EEE (electrical, electronic, and electromechanical) parts wire and the approved electrical wire and cable. The SSF PDRD (Program Definition and Requirements Document) language problems and resolution are reviewed. The cable routing to and from the SPDA's is presented as diagrams and the wire recommendations and characteristics are given.

  14. Space-Based Solar Power System Architecture (United States)


    and the efficiencies reached by those high volumes is game -changing. By lowering the cost to orbit so substantially, and by providing safe and routine...chosen the same operational orbit for their notional space based solar power satellite. However, due to the prohibitive costs, a pathfinder or...that orbit will minimize the number of launches required to put the satellite into orbit while still allowing a pathfinder satellite to prove

  15. Human exploration of space and power development (United States)

    Cohen, Aaron

    The possible role of Solar Power Satellites (SPS) in advancing the goals of the Space Exploration Initiative is considered. Three approaches are examined: (1) the use of lunar raw materials to construct a large SPS in GEO, (2) the construction of a similar system on the lunar surface, and (3) a combination of (1) and (2). Emphasis is given to the mining of He-3 from the moon and its use by the SPS.

  16. Bimodal Nuclear Thermal Rocket Analysis Developments (United States)

    Belair, Michael; Lavelle, Thomas; Saimento, Charles; Juhasz, Albert; Stewart, Mark


    Nuclear thermal propulsion has long been considered an enabling technology for human missions to Mars and beyond. One concept of operations for these missions utilizes the nuclear reactor to generate electrical power during coast phases, known as bimodal operation. This presentation focuses on the systems modeling and analysis efforts for a NERVA derived concept. The NERVA bimodal operation derives the thermal energy from the core tie tube elements. Recent analysis has shown potential temperature distributions in the tie tube elements that may limit the thermodynamic efficiency of the closed Brayton cycle used to generate electricity with the current design. The results of this analysis are discussed as well as the potential implications to a bimodal NERVA type reactor.

  17. Photovoltaics for high capacity space power systems (United States)

    Flood, Dennis J.


    The anticipated energy requirements of future space missions will grow by factors approaching 100 or more, particularly as a permanent manned presence is established in space. The advances that can be expected in solar array performance and lifetime, when coupled with advanced, high energy density storage batteries and/or fuel cells, will continue to make photovoltaic energy conversion a viable power generating option for the large systems of the future. The specific technologies required to satisfy any particular set of power requirements will vary from mission to mission. Nonetheless, in almost all cases the technology push will be toward lighter weight and higher efficiency, whether of solar arrays of storage devices. This paper will describe the content and direction of the current NASA program in space photovoltaic technology. The paper will also discuss projected system level capabilities of photovoltaic power systems in the context of some of the new mission opportunities under study by NASA, such as a manned lunar base, and a manned visit to Mars.

  18. Materials technology for Stirling space power converters (United States)

    Baggenstoss, William; Mittendorf, Donald


    This program was conducted in support of the NASA LeRC development of the Stirling power converter (SPC) for space power applications. The objectives of this contract were: (1) to perform a technology review and analyses to support the evaluation of materials issues for the SPC; (2) to evaluate liquid metal compatibility issues of the SPC; (3) to evaluate and define a transient liquid phase diffusion bonding (TLPDB) process for the SPC joints to the Udimet 720 heater head; and (4) to evaluate alternative (to the TLPDB) joining techniques. In the technology review, several aspects of the current Stirling design were examined including the power converter assembly process, materials joining, gas bearings, and heat exchangers. The supporting analyses included GLIMPS power converter simulation in support of the materials studies, and system level analysis in support of the technology review. The liquid metal compatibility study evaluated process parameters for use in the Stirling power converter. The alternative joining techniques study looked at the applicability of various joining techniques to the Stirling power converter requirements.

  19. Sandwich module testing for space solar power (United States)

    Jaffe, Paul

    Solar power satellites have been envisioned as a means to provide electricity for terrestrial use. The approach entails collection of solar energy in space and its wireless transmission to the earth. This potentially gives the benefit of provision of baseload power while avoiding the losses due to the day/night cycle and tropospheric effects that are associated with terrestrial solar power. Proponents have contended that the implementation of such systems could offer energy security, environmental, and technological advantages to those who would undertake their development. Among recent implementations commonly proposed for SSP, the Modular Symmetrical Concentrator and other modular concepts have received considerable attention. Each employs an array of modules for performing conversion of concentrated sunlight into microwaves or laser beams for transmission to earth. The research described herein details efforts in the development and testing of photovoltaic arrays, power electronics, microwave conversion electronics, and antennas for 2.45 GHz microwave-based “ sandwich” module prototypes. Prototypes were designed, fabricated, and subjected to the challenging conditions inherent in the space environment, including the solar concentration levels in which an array of modules might be required to operate.

  20. Performance tuned radioisotope thermophotovoltaic space power system (United States)

    Horne, W. E.; Morgan, M. D.; Saban, S. B.


    The trend in space exploration is to use many small, low-cost, special-purpose satellites instead of the large, high-cost, multipurpose satellites used in the past. As a result of this new trend, there is a need for lightweight, efficient, and compact radioisotope fueled electrical power generators. This paper presents an improved design for a radioisotope thermophotovoltaic (RTPV) space power system in the 10 W to 20 W class which promises up to 37.6 watts at 30.1% efficiency and 25 W/kg specific power. The RTPV power system concept has been studied and compared to radioisotope thermoelectric generators (RTG) radioisotope, Stirling generators and alkali metal thermal electric conversion (AMTEC) generators (Schock, 1995). The studies indicate that RTPV has the potential to be the lightest weight, most efficient and most reliable of the three concepts. However, in spite of the efficiency and light weight, the size of the thermal radiator required to eliminate excess heat from the PV cells and the lack of actual system operational performance data are perceived as obstacles to RTPV acceptance for space applications. Between 1994 and 1997 EDTEK optimized the key converter components for an RTPV generator under Department of Energy (DOE) funding administered via subcontracts to Orbital Sciences Corporation (OSC) and EG&G Mound Applied Technologies Laboratory (Horne, 1995). The optimized components included a resonant micromesh infrared bandpass filter, low-bandgap GaSb PV cells and cell arrays. Parametric data from these components were supplied to OSC who developed and analyzed the performance of 100 W, 20 W, and 10 W RTPV generators. These designs are described in references (Schock 1994, 1995 and 1996). Since the performance of each class of supply was roughly equivalent and simply scaled with size, this paper will consider the OSC 20 W design as a baseline. The baseline 20-W RTPV design was developed by Schock, et al of OSC and has been presented elsewhere. The

  1. Maturing Technologies for Stirling Space Power Generation (United States)

    Wilson, Scott D.; Nowlin, Brentley C.; Dobbs, Michael W.; Schmitz, Paul C.; Huth, James


    Stirling Radioisotope Power Systems (RPS) are being developed as an option to provide power on future space science missions where robotic spacecraft will orbit, flyby, land or rove. A Stirling Radioisotope Generator (SRG) could offer space missions a more efficient power system that uses one fourth of the nuclear fuel and decreases the thermal footprint of the current state of the art. The RPS Program Office, working in collaboration with the U.S. Department of Energy (DOE), manages projects to develop thermoelectric and dynamic power systems, including Stirling Radioisotope Generators (SRGs). The Stirling Cycle Technology Development (SCTD) Project, located at Glenn Research Center (GRC), is developing Stirling-based subsystems, including convertors and controllers. The SCTD Project also performs research that focuses on a wide variety of objectives, including increasing convertor temperature capability to enable new environments, improving system reliability or fault tolerance, reducing mass or size, and developing advanced concepts that are mission enabling. Research activity includes maturing subsystems, assemblies, and components to prepare them for infusion into future convertor and generator designs. The status of several technology development efforts are described here. As part of the maturation process, technologies are assessed for readiness in higher-level subsystems. To assess the readiness level of the Dual Convertor Controller (DCC), a Technology Readiness Assessment (TRA) was performed and the process and results are shown. Stirling technology research is being performed by the SCTD Project for NASA's RPS Program Office, where tasks focus on maturation of Stirling-based systems and subsystems for future space science missions.

  2. Tie Tube Heat Transfer Modeling for Bimodal Nuclear Thermal Rockets (United States)

    Clough, Joshua A.; Starkey, Ryan P.; Lewis, Mark J.; Lavelle, Thomas M.


    Bimodal nuclear thermal rocket systems have been shown to reduce the weight and cost of space vehicles to Mars and beyond by utilizing the reactor for power generation in the relatively long duration between burns in an interplanetary trajectory. No information, however, is available regarding engine and reactor-level operation of such bimodal systems. The purpose of this project is to generate engine and reactor models with sufficient fidelity and flexibility to accurately study the component-level effects of operating a propulsion-designed reactor at power generation levels. Previous development of a 1-D reactor and tie tube model found that ignoring heat generation inside of the tie tube leads to under-prediction of the temperature change and over-prediction of pressure change across the tie tube. This paper will present the development and results of a tie tube model that has been extended to account for heat generation, specifically in the moderator layer. This model is based on a 1-D distribution of power in the fuel elements and tie tubes, as a precursor to an eventual neutron-driven reactor model.

  3. Liquid Metal Cooled Reactor for Space Power (United States)

    Weitzberg, Abraham


    The conceptual design is for a liquid metal (LM) cooled nuclear reactor that would provide heat to a closed Brayton cycle (CBC) power conversion subsystem to provide electricity for electric propulsion thrusters and spacecraft power. The baseline power level is 100 kWe to the user. For long term power generation, UN pin fuel with Nb1Zr alloy cladding was selected. As part of the SP-100 Program this fuel demonstrated lifetime with greater than six atom percent burnup, at temperatures in the range of 1400-1500 K. The CBC subsystem was selected because of the performance and lifetime database from commercial and aircraft applications and from prior NASA and DOE space programs. The high efficiency of the CBC also allows the reactor to operate at relatively low power levels over its 15-year life, minimizing the long-term power density and temperature of the fuel. The scope of this paper is limited to only the nuclear components that provide heated helium-xenon gas to the CBC subsystem. The principal challenge for the LM reactor concept was to design the reactor core, shield and primary heat transport subsystems to meet mission requirements in a low mass configuration. The LM concept design approach was to assemble components from prior programs and, with minimum change, determine if the system met the objective of the study. All of the components are based on technologies having substantial data bases. Nuclear, thermalhydraulic, stress, and shielding analyses were performed using available computer codes. Neutronics issues included maintaining adequate operating and shutdown reactivities, even under accident conditions. Thermalhydraulic and stress analyses calculated fuel and material temperatures, coolant flows and temperatures, and thermal stresses in the fuel pins, components and structures. Using conservative design assumptions and practices, consistent with the detailed design work performed during the SP-100 Program, the mass of the reactor, shield, primary heat

  4. A Space Based Solar Power Satellite System (United States)

    Engel, J. M.; Polling, D.; Ustamujic, F.; Yaldiz, R.; et al.


    (SPoTS) supplying other satellites with energy. SPoTS is due to be commercially viable and operative in 2020. of Technology designed the SPoTS during a full-time design period of six weeks as a third year final project. The team, organized according to the principles of systems engineering, first conducted a literature study on space wireless energy transfer to select the most suitable candidates for use on the SPoTS. After that, several different system concepts have been generated and evaluated, the most promising concept being worked out in greater detail. km altitude. Each SPoTS satellite has a 50m diameter inflatable solar collector that focuses all received sunlight. Then, the received sunlight is further redirected by means of four pointing mirrors toward four individual customer satellites. A market-analysis study showed, that providing power to geo-stationary communication satellites during their eclipse would be most beneficial. At arrival at geo-stationary orbit, the focused beam has expended to such an extent that its density equals one solar flux. This means that customer satellites can continue to use their regular solar arrays during their eclipse for power generation, resulting in a satellite battery mass reduction. the customer satellites in geo-stationary orbit, the transmitted energy beams needs to be pointed with very high accuracy. Computations showed that for this degree of accuracy, sensors are needed, which are not mainstream nowadays. Therefore further research must be conducted in this area in order to make these high-accuracy-pointing systems commercially attractive for use on the SPoTS satellites around 2020. Total 20-year system lifetime cost for 18 SPoT satellites are estimated at approximately USD 6 billion [FY2001]. In order to compete with traditional battery-based satellite power systems or possible ground based wireless power transfer systems the price per kWh for the customer must be significantly lower than the present one

  5. Operators of Approximations and Approximate Power Set Spaces

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xian-yong; MO Zhi-wen; SHU Lan


    Boundary inner and outer operators are introduced; and union, intersection, complement operators of approximations are redefined. The approximation operators have a good property of maintaining union, intersection, complement operators, so the rough set theory has been enriched from the operator-oriented and set-oriented views. Approximate power set spaces are defined, and it is proved that the approximation operators are epimorphisms from power set space to approximate power set spaces. Some basic properties of approximate power set space are got by epimorphisms in contrast to power set space.

  6. Heat pipe cooled reactors for multi-kilowatt space power supplies

    Energy Technology Data Exchange (ETDEWEB)

    Ranken, W.A.; Houts, M.G.


    Three nuclear reactor space power system designs are described that demonstrate how the use of high temperature heat pipes for reactor heat transport, combined with direct conversion of heat to electricity, can result in eliminating pumped heat transport loops for both primary reactor cooling and heat rejection. The result is a significant reduction in system complexity that leads to very low mass systems with high reliability, especially in the power range of 1 to 20 kWe. In addition to removing heat exchangers, electromagnetic pumps, and coolant expansion chambers, the heat pipe/direct conversion combination provides such capabilities as startup from the frozen state, automatic rejection of reactor decay heat in the event of emergency or accidental reactor shutdown, and the elimination of single point failures in the reactor cooling system. The power system designs described include a thermoelectric system that can produce 1 to 2 kWe, a bimodal modification of this system to increase its power level to 5 kWe and incorporate high temperature hydrogen propulsion capability, and a moderated thermionic reactor concept with 5 to 20 kWe power output that is based on beryllium modules that thermally couple cylindrical thermionic fuel elements (TFEs) to radiator heat pipes.

  7. Heat pipe cooled reactors for multi-kilowatt space power supplies (United States)

    Ranken, W. A.; Houts, M. G.

    Three nuclear reactor space power system designs are described that demonstrate how the use of high temperature heat pipes for reactor heat transport, combined with direct conversion of heat to electricity, can result in eliminating pumped heat transport loops for both primary reactor cooling and heat rejection. The result is a significant reduction in system complexity that leads to very low mass systems with high reliability, especially in the power range of 1 to 20 kWe. In addition to removing heat exchangers, electromagnetic pumps, and coolant expansion chambers, the heat pipe/direct conversion combination provides such capabilities as startup from the frozen state, automatic rejection of reactor decay heat in the event of emergency or accidental reactor shutdown, and the elimination of single point failures in the reactor cooling system. The power system designs described include a thermoelectric system that can produce 1 to 2 kWe, a bimodal modification of this system to increase its power level to 5 kWe and incorporate high temperature hydrogen propulsion capability, and a moderated thermionic reactor concept with 5 to 20 kWe power output that is based on beryllium modules that thermally couple cylindrical thermionic fuel elements (TFE's) to radiator heat pipes.

  8. Is power-space a continuum? Distance effect during power judgments. (United States)

    Jiang, Tianjiao; Zhu, Lei


    Despite the increasing evidence suggesting that power processing can activate vertical space schema, it still remains unclear whether this power-space is dichotomic or continuous. Here we tested the nature of the power-space by the distance effect, a continuous property of space cognition. In two experiments, participants were required to judge the power of one single word (Experiment 1) or compare the power of two words presented in pairs (Experiment 2). The power distance was indexed by the absolute difference of power ratings. Results demonstrated that reaction time decreased with the power distance, whereas accuracy increased with the power distance. The findings indicated that different levels of power were presented as different vertical heights, implying that there was a common mechanism underlying space and power cognition.

  9. Recent Advances in Nuclear Powered Electric Propulsion for Space Exploration (United States)

    Cassady, R. Joseph; Frisbee, Robert H.; Gilland, James H.; Houts, Michael G.; LaPointe, Michael R.; Maresse-Reading, Colleen M.; Oleson, Steven R.; Polk, James E.; Russell, Derrek; Sengupta, Anita


    Nuclear and radioisotope powered electric thrusters are being developed as primary in-space propulsion systems for potential future robotic and piloted space missions. Possible applications for high power nuclear electric propulsion include orbit raising and maneuvering of large space platforms, lunar and Mars cargo transport, asteroid rendezvous and sample return, and robotic and piloted planetary missions, while lower power radioisotope electric propulsion could significantly enhance or enable some future robotic deep space science missions. This paper provides an overview of recent U.S. high power electric thruster research programs, describing the operating principles, challenges, and status of each technology. Mission analysis is presented that compares the benefits and performance of each thruster type for high priority NASA missions. The status of space nuclear power systems for high power electric propulsion is presented. The paper concludes with a discussion of power and thruster development strategies for future radioisotope electric propulsion systems,

  10. Advanced Space Power Systems (ASPS): Regenerative Fuel Cells (RFC) Project (United States)

    National Aeronautics and Space Administration — The objective of the regenerative fuel cell project element is to develop power and energy storage technologies that enable new capabilities for future human space...

  11. An Advanced Light Weight Recuperator for Space Power Systems Project (United States)

    National Aeronautics and Space Administration — Nuclear Electric Propulsion (NEP) technology holds great promise for power and propulsion demands of NASA current and future deep space explorations. Closed Brayton...

  12. High Power Uplink Amplifier for Deep Space Communications Project (United States)

    National Aeronautics and Space Administration — Critical to the success of delivering on the promise of deep space optical communications is the creation of a stable and reliable high power multichannel optical...

  13. An Advanced Light Weight Recuperator for Space Power Systems Project (United States)

    National Aeronautics and Space Administration — Closed Brayton Cycle (CBC) space power system is one of the most efficient energy conversion technologies for nuclear and solar electric propulsion. The recuperator...

  14. The Space Triad: A Joint Concept for Space Power (United States)


    fact, President Eisenhower decided to create the National Aeronautics and Space Administration ( NASA ), separate from the Department of Defense (DOD...declining stock prices, steady layoffs , program failures and cost and schedule overruns. Without a sufficient base of interesting, leading edge... NASA , parallel to the military’s space efforts, was in large part due to the desire to make space a sanctuary. Understanding space is no longer a

  15. Electric power management for the International Space Station experiment racks

    Energy Technology Data Exchange (ETDEWEB)

    Burcham, M. [Boeing Missile and Space, Huntsville, AL (United States); Darty, M.A.; Thibodeau, P.E. [McDonnell Douglas Aerospace, Huntsville, AL (United States); Coe, R. [SCI Systems, Inc., Huntsville, AL (United States); Dunn, M. [Europa Ltd., Glenrothes (United Kingdom)


    An intelligent, all solid state, electric power management system for International Space Station experiment racks is described. This power system is implemented via redundant internal microcomputers, controlling hybridized solid state power controllers in response to 1553B data bus commands. The solid state power controllers are programmable for current trip level and for normally-open or normally-closed operation.

  16. Space power development impact on technology requirements (United States)

    Cassidy, J. F.; Fitzgerald, T. J.; Gilje, R. I.; Gordon, J. D.


    The paper is concerned with the selection of a specific spacecraft power technology and the identification of technology development to meet system requirements. Requirements which influence the selection of a given technology include the power level required, whether the load is constant or transient in nature, and in the case of transient loads, the time required to recover the power, and overall system safety. Various power technologies, such as solar voltaic power, solar dynamic power, nuclear power systems, and electrochemical energy storage, are briefly described.

  17. Nuclear space power safety and facility guidelines study

    Energy Technology Data Exchange (ETDEWEB)

    Mehlman, W.F.


    This report addresses safety guidelines for space nuclear reactor power missions and was prepared by The Johns Hopkins University Applied Physics Laboratory (JHU/APL) under a Department of Energy grant, DE-FG01-94NE32180 dated 27 September 1994. This grant was based on a proposal submitted by the JHU/APL in response to an {open_quotes}Invitation for Proposals Designed to Support Federal Agencies and Commercial Interests in Meeting Special Power and Propulsion Needs for Future Space Missions{close_quotes}. The United States has not launched a nuclear reactor since SNAP 10A in April 1965 although many Radioisotope Thermoelectric Generators (RTGs) have been launched. An RTG powered system is planned for launch as part of the Cassini mission to Saturn in 1997. Recently the Ballistic Missile Defense Office (BMDO) sponsored the Nuclear Electric Propulsion Space Test Program (NEPSTP) which was to demonstrate and evaluate the Russian-built TOPAZ II nuclear reactor as a power source in space. As of late 1993 the flight portion of this program was canceled but work to investigate the attributes of the reactor were continued but at a reduced level. While the future of space nuclear power systems is uncertain there are potential space missions which would require space nuclear power systems. The differences between space nuclear power systems and RTG devices are sufficient that safety and facility requirements warrant a review in the context of the unique features of a space nuclear reactor power system.

  18. High-power converters for space applications (United States)

    Park, J. N.; Cooper, Randy


    Phase 1 was a concept definition effort to extend space-type dc/dc converter technology to the megawatt level with a weight of less than 0.1 kg/kW (220 lb./MW). Two system designs were evaluated in Phase 1. Each design operates from a 5 kV stacked fuel cell source and provides a voltage step-up to 100 kV at 10 A for charging capacitors (100 pps at a duty cycle of 17 min on, 17 min off). Both designs use an MCT-based, full-bridge inverter, gaseous hydrogen cooling, and crowbar fault protection. The GE-CRD system uses an advanced high-voltage transformer/rectifier filter is series with a resonant tank circuit, driven by an inverter operating at 20 to 50 kHz. Output voltage is controlled through frequency and phase shift control. Fast transient response and stability is ensured via optimal control. Super-resonant operation employing MCTs provides the advantages of lossless snubbing, no turn-on switching loss, use of medium-speed diodes, and intrinsic current limiting under load-fault conditions. Estimated weight of the GE-CRD system is 88 kg (1.5 cu ft.). Efficiency of 94.4 percent and total system loss is 55.711 kW operating at 1 MW load power. The Maxwell system is based on a resonance transformer approach using a cascade of five LC resonant sections at 100 kHz. The 5 kV bus is converted to a square wave, stepped-up to a 100 kV sine wave by the LC sections, rectified, and filtered. Output voltage is controlled with a special series regulator circuit. Estimated weight of the Maxwell system is 83.8 kg (4.0 cu ft.). Efficiency is 87.2 percent and total system loss is 146.411 kW operating at 1 MW load power.

  19. Enabling the space exploration initiative: NASA's exploration technology program in space power (United States)

    Bennett, Gary L.; Cull, Ronald C.


    Space power requirements for Space Exploration Initiative (SEI) are reviewed, including the results of a NASA 90-day study and reports by the National Research Council, the American Institute of Aeronautics and Astronautics (AIAA), NASA, the Advisory Committee on the Future of the U.S. Space Program, and the Synthesis Group. The space power requirements for the SEI robotic missions, lunar spacecraft, Mars spacecraft, and human missions are summarized. Planning for exploration technology is addressed, including photovoltaic, chemical and thermal energy conversion; high-capacity power; power and thermal management for the surface, Earth-orbiting platform and spacecraft; laser power beaming; and mobile surface systems.

  20. Ten Propositions Regarding Space Power: The Dawn of a Space Force (United States)


    The answer is yes. Space Power: What fundamenta strengths best characterize Historical Background the potentia of military space power? What are space...p1yiasenhrwlrfgh’Ie itiphysical strength , or will to fight."’ The United The key for space power to support all levels States is more space dependent than any...aviatwon will beUSFre c a a xdiarj and the equite US Space Force: amount omo , a compared with the other No Longer a Question e wben ect to theof a deci i0

  1. Detecting bimodality in astronomical datasets (United States)

    Ashman, Keith A.; Bird, Christina M.; Zepf, Stephen E.


    We discuss statistical techniques for detecting and quantifying bimodality in astronomical datasets. We concentrate on the KMM algorithm, which estimates the statistical significance of bimodality in such datasets and objectively partitions data into subpopulations. By simulating bimodal distributions with a range of properties we investigate the sensitivity of KMM to datasets with varying characteristics. Our results facilitate the planning of optimal observing strategies for systems where bimodality is suspected. Mixture-modeling algorithms similar to the KMM algorithm have been used in previous studies to partition the stellar population of the Milky Way into subsystems. We illustrate the broad applicability of KMM by analyzing published data on globular cluster metallicity distributions, velocity distributions of galaxies in clusters, and burst durations of gamma-ray sources. FORTRAN code for the KMM algorithm and directions for its use are available from the authors upon request.

  2. Controllable synthesis of high loading LiFePO4/C nanocomposites using bimodal mesoporous carbon as support for high power Li-ion battery cathodes

    Institute of Scientific and Technical Information of China (English)

    Fei; Cheng; Duo; Li; Anhui; Lu; Wencui; Li


    Mesoporous LiFePO4/C composites containing 80 wt% of highly dispersed LiFePO4 nanoparticles(4-6 nm) were fabricated using bimodal mesoporous carbon(BMC) as continuous conductive networks. The unique pore structure of BMC not only promises good particle connectivity for LiFePO4, but also acts as a rigid nano-confinement support that controls the particle size. Furthermore, the capacities were investigated respectively based on the weight of LiFePO4 and the whole composite. When calculated based on the weight of the whole composite, it is 120 mAh·g-1at 0.1 C of the high loading electrode and 42 mAh·g-1at 10 C of the low loading electrode. The electrochemical performance shows that high LiFePO4 loading benefits large tap density and contributes to the energy storage at low rates, while the electrode with low content of LiFePO4 displays superior high rate performance, which can mainly be due to the small particle size, good dispersion and high utilization of the active material, thus leading to a fast ion and electron diffusion.

  3. Modern Air&Space Power and political goals at war (United States)

    Özer, Güngör.


    Modern AirandSpace Power is increasingly becoming a political tool. In this article, AirandSpacePower as a political tool will be discussed. The primary purpose of this article is to search how AirandSpacePower can provide contributions to security and also determine if it may reach the political goals on its own at war by SWOT Analysis Method and analysing the role of AirandSpace Power in Operation Unified Protector (Libya) as a case study. In conclusion, AirandSpacePower may not be sufficient to win the political goals on its own. However it may reach the political aims partially against the adversary on its own depending upon the situations. Moreover it can alone persuade the adversary to alter its behavior(s) in war.

  4. Transactions of the fifth symposium on space nuclear power systems

    Energy Technology Data Exchange (ETDEWEB)

    El-Genk, M.S.; Hoover, M.D. (eds.)


    This paper contains the presented papers at the fourth symposium on space nuclear power systems. Topics of these paper include: space nuclear missions and applications, reactors and shielding, nuclear electric and nuclear propulsion, high-temperature materials, instrumentation and control, energy conversion and storage, space nuclear fuels, thermal management, nuclear safety, simulation and modeling, and multimegawatt system concepts. (LSP)

  5. Transactions of the fourth symposium on space nuclear power systems

    Energy Technology Data Exchange (ETDEWEB)

    El-Genk, M.S.; Hoover, M.D. (eds.)


    This paper contains the presented papers at the fourth symposium on space nuclear power systems. Topics of these papers include: space nuclear missions and applications, reactors and shielding, nuclear electric and nuclear propulsion, refractory alloys and high-temperature materials, instrumentation and control, energy conversion and storage, space nuclear fuels, thermal management, nuclear safety, simulation and modeling, and multimegawatt system concepts. (LSP)

  6. SNPSAM - Space Nuclear Power System Analysis Model (United States)

    El-Genk, Mohamed S.; Seo, Jong T.

    The current version of SNPSAM is described, and the results of the integrated thermoeletric SP-100 system performance studies using SNPSAM are reported. The electric power output, conversion efficiency, coolant temperatures, and specific pumping power of the system are calculated as functions of the reactor thermal power and the liquid metal coolant type (Li or NaK-78) during steady state operation. The transient behavior of the system is also discussed.

  7. Silicon Carbide Based Power Mangement and Distribution for Space Nuclear Power Systems Project (United States)

    National Aeronautics and Space Administration — In this SBIR project, APEI, Inc. is proposing to develop a high efficiency, rad-hard, 100's kWe power management and distribution (PMAD) system for space nuclear...

  8. Key issues in space nuclear power challenges for the future (United States)

    Brandhorst, Henry W., Jr.


    The future appears rich in missions that will extend the frontiers of knowledge, human presence in space, and opportunities for profitable commerce. Key to the success of these ventures is the availability of plentiful, cost effective electric power and assured, low cost access to space. While forecasts of space power needs are problematic, an assessment of future needs based on terrestrial experience has been made. These needs fall into three broad categories: survival, self sufficiency, and industrialization. The cost of delivering payloads to orbital locations from LEO to Mars has been determined and future launch cost reductions projected. From these factors, then, projections of the performance necessary for future solar and nuclear space power options has been made. These goals are largely dependent upon orbital location and energy storage needs. Finally the cost of present space power systems has been determined and projections made for future systems.

  9. Green Applications for Space Power Project (United States)

    National Aeronautics and Space Administration — A key technical difference (aside from the differences in toxicity) between Hydrazine and the green propellant alternatives is the combustion temperature.  Both...

  10. Solar Power Satellites for Space Exploration and Applications (United States)

    Cougnet, C.; Sein, E.; Celeste, A.; Summerer, L.


    Power generation is one of the crucial elements of space vehicles and of future infrastructures on planets and moons. The increased demand for power faces many constraints, in particular the sizing of the power generation system also driven by eclipse periods and the solar intensity at the operational spot. In the medium term, Earth orbiting platforms will require higher power levels. Interplanetary exploration vehicles face the problem of distance to the Sun, especially when large amount of power may be needed. Large infrastructures on Moon and planets, like Mars, are constrained by environment attenuation, long eclipse or distance to the Sun. New systems and technologies have to be found, which go beyond simple improvements of the current technologies. Solar Power Satellite (SPS) systems, based on wireless power transmission, are attractive candidate solutions to provide power to space vehicles or to elements on planet surface. Studies have been carried out for many years on the problem of providing renewable electrical energy from space to Earth with SPS. This paper reviews the main results of an ESA funded study, led by EADS Astrium with the support of the Université of La Réunion, which assessed the utilisation of SPS concepts for space-to-space and space-to-planet applications.

  11. High temperature power electronics for space (United States)

    Hammoud, Ahmad N.; Baumann, Eric D.; Myers, Ira T.; Overton, Eric


    A high temperature electronics program at NASA Lewis Research Center focuses on dielectric and insulating materials research, development and testing of high temperature power components, and integration of the developed components and devices into a demonstrable 200 C power system, such as inverter. An overview of the program and a description of the in-house high temperature facilities along with experimental data obtained on high temperature materials are presented.


    This report outlines the capabilities and limitations of a hybrid solar cell- fuel cell space power subsystem by comparing the proposed hybrid conventional power subsystem devices. The comparisons are based on projected 1968 capability in the areas of primary and secondary battery, fuel ... cell , solar cell, and chemical dynamic power subsystems. The purpose of the investigation was to determine the relative merits of a hybrid power

  13. Automated electric power management and control for Space Station Freedom (United States)

    Dolce, James L.; Mellor, Pamela A.; Kish, James A.


    A comprehensive automation design is being developed for Space Station Freedom's electric power system. It strives to increase station productivity by applying expert systems and conventional algorithms to automate power system operation. An integrated approach to the power system command and control problem is defined and used to direct technology development in: diagnosis, security monitoring and analysis, battery management, and cooperative problem-solving for resource allocation. The prototype automated power system is developed using simulations and test-beds.

  14. Transfer learning for bimodal biometrics recognition (United States)

    Dan, Zhiping; Sun, Shuifa; Chen, Yanfei; Gan, Haitao


    Biometrics recognition aims to identify and predict new personal identities based on their existing knowledge. As the use of multiple biometric traits of the individual may enables more information to be used for recognition, it has been proved that multi-biometrics can produce higher accuracy than single biometrics. However, a common problem with traditional machine learning is that the training and test data should be in the same feature space, and have the same underlying distribution. If the distributions and features are different between training and future data, the model performance often drops. In this paper, we propose a transfer learning method for face recognition on bimodal biometrics. The training and test samples of bimodal biometric images are composed of the visible light face images and the infrared face images. Our algorithm transfers the knowledge across feature spaces, relaxing the assumption of same feature space as well as same underlying distribution by automatically learning a mapping between two different but somewhat similar face images. According to the experiments in the face images, the results show that the accuracy of face recognition has been greatly improved by the proposed method compared with the other previous methods. It demonstrates the effectiveness and robustness of our method.

  15. Performance evaluation of space solar Brayton cycle power systems (United States)

    Diao, Zheng-Gang


    Unlike gas turbine power systems which consume chemical or nuclear energy, the energy consumption and/or cycle efficiency should not be a suitable criterion for evaluating the performance of space solar Brayton cycle power. A new design goal, life cycle cost, can combine all the power system characteristics, such as mass, area, and station-keeping propellant, into a unified criterion. Effects of pressure ratio, recuperator effectiveness, and compressor inlet temperature on life cycle cost were examined. This method would aid in making design choices for a space power system.

  16. Mobility and power in networked European space

    DEFF Research Database (Denmark)

    Richardson, Tim; Jensen, Ole B.

    This paper seeks to contribute to debates about how urban, social and critical theory can conceptualise the socio-technologies of connection, resilience, mobility, and collapse in contemporary urban space. The paper offers a theoretical frame for conceptualising this New Urban Condition, focusing...

  17. Exploration mission enhancements possible with power beaming. [Space Applications Power Beaming

    Energy Technology Data Exchange (ETDEWEB)

    Bamberger, J.A.; Coomes, E.P. (Pacific Northwest Lab., Richland, WA (USA)); Segna, D.R. (USDOE Richland Operations Office, WA (USA))


    A key factor in the exploration and development of the space frontier is the availability of energy where and when it is needed. Currently all space satellites and platforms include self-contained power systems that supply the energy necessary to accomplish mission objectives. An alternative approach is to couple advanced high power system with energy beam transmitters and energy receivers to form an infrastructure of a space power utility where a central power system provides power to multiple users. Major space activities, such as low Earth orbit space commercialization and the colonization of the Moon or Mars, would benefit significantly from a central power generation and transmission system. This paper describes the power-beaming concept and system components as applied to space power generation and distribution in support of the Space Exploration Initiative. Beam-power scenarios are discussed including commonality of systems and hardware with cargo transport vehicles, power beaming from orbit to stationary and mobile users on the Lunar and Mars surfaces, and other surface applications. 6 refs.

  18. Technology Status of Thermionic Fuel Elements for Space Nuclear Power (United States)

    Holland, J. W.; Yang, L.


    Thermionic reactor power systems are discussed with respect to their suitability for space missions. The technology status of thermionic emitters and sheath insulator assemblies is described along with testing of the thermionic fuel elements.

  19. Striction-based Power Monitoring in Space Environment Project (United States)

    National Aeronautics and Space Administration — The program delivers a completely new technology solution to isolation and sensing of power flow (current and voltage). Based on striction materials technology,...

  20. Models for Multimegawatt Space Power Systems (United States)


    to be exceeded. To determine this specific power limit we will consider a fuel particle comprised of a central fuel kernel which is coated by layers...Commissariat A L’Energie Atomique Dept. des Etudes Mechaniques et Thermiques 33 Rue de La Federation 75015 Paris FRANCE Lt. Col. H. Pugh AFSTC

  1. Intelligent (Autonomous) Power Controller Development for Human Deep Space Exploration (United States)

    Soeder, James; Raitano, Paul; McNelis, Anne


    As NASAs Evolvable Mars Campaign and other exploration initiatives continue to mature they have identified the need for more autonomous operations of the power system. For current human space operations such as the International Space Station, the paradigm is to perform the planning, operation and fault diagnosis from the ground. However, the dual problems of communication lag as well as limited communication bandwidth beyond GEO synchronous orbit, underscore the need to change the operation methodology for human operation in deep space. To address this need, for the past several years the Glenn Research Center has had an effort to develop an autonomous power controller for human deep space vehicles. This presentation discusses the present roadmap for deep space exploration along with a description of conceptual power system architecture for exploration modules. It then contrasts the present ground centric control and management architecture with limited autonomy on-board the spacecraft with an advanced autonomous power control system that features ground based monitoring with a spacecraft mission manager with autonomous control of all core systems, including power. It then presents a functional breakdown of the autonomous power control system and examines its operation in both normal and fault modes. Finally, it discusses progress made in the development of a real-time power system model and how it is being used to evaluate the performance of the controller and well as using it for verification of the overall operation.

  2. Heat pipe reactors for space power applications (United States)

    Koenig, D. R.; Ranken, W. A.; Salmi, E. W.


    A family of heat pipe reactors design concepts has been developed to provide heat to a variety of electrical conversion systems. Three power plants are described that span the power range 1-500 kWe and operate in the temperature range 1200-1700 K. The reactors are fast, compact, heat-pipe cooled, high-temperature nuclear reactors fueled with fully enriched refractory fuels, UC-ZrC or UO2. Each fuel element is cooled by an axially located molybdenum heat pipe containing either sodium or lithium vapor. Virtues of the reactor designs are the avoidance of single-point failure mechanisms, the relatively high operating temperature, and the expected long lifetimes of the fuel element components.

  3. Center for Space Power and Advanced Electronics, Auburn University (United States)

    Deis, Dan W.; Hopkins, Richard H.


    The union of Auburn University's Center for Space Power and Advanced Electronics and the Westinghouse Science and Technology Center to form a Center for the Commercial Development of Space (CCDS) is discussed. An area of focus for the CCDS will be the development of silicon carbide electronics technology, in terms of semiconductors and crystal growth. The discussion is presented in viewgraph form.

  4. Systems definition space based power conversion systems: Executive summary (United States)


    Potential space-located systems for the generation of electrical power for use on earth were investigated. These systems were of three basic types: (1) systems producing electrical power from solar energy; (2) systems producing electrical power from nuclear reactors; (3) systems for augmenting ground-based solar power plants by orbital sunlight reflectors. Configurations implementing these concepts were developed through an optimization process intended to yield the lowest cost for each. A complete program was developed for each concept, identifying required production rates, quantities of launches, required facilities, etc. Each program was costed in order to provide the electric power cost appropriate to each concept.

  5. Space nuclear power, propulsion, and related technologies.

    Energy Technology Data Exchange (ETDEWEB)

    Berman, Marshall


    Sandia National Laboratories (Sandia) is one of the nation's largest research and development (R&D) facilities, with headquarters at Albuquerque, New Mexico; a laboratory at Livermore, California; and a test range near Tonopah, Nevada. Smaller testing facilities are also operated at other locations. Established in 1945, Sandia was operated by the University of California until 1949, when, at the request of President Truman, Sandia Corporation was formed as a subsidiary of Bell Lab's Western Electric Company to operate Sandia as a service to the U.S. Government without profit or fee. Sandia is currently operated for the U.S. Department of Energy (DOE) by AT&T Technologies, Inc., a wholly-owned subsidiary of AT&T. Sandia's responsibility is national security programs in defense and energy with primary emphasis on nuclear weapon research and development (R&D). However, Sandia also supports a wide variety of projects ranging from basic materials research to the design of specialized parachutes. Assets, owned by DOE and valued at more than $1.2 billion, include about 600 major buildings containing about 372,000 square meters (m2) (4 million square feet [ft2]) of floor space, located on land totalling approximately 1460 square kilometers (km2) (562 square miles [mi]). Sandia employs about 8500 people, the majority in Albuquerque, with about 1000 in Livermore. Approximately 60% of Sandia's employees are in technical and scientific positions, and the remainder are in crafts, skilled labor, and administrative positions. As a multiprogram national laboratory, Sandia has much to offer both industrial and government customers in pursuing space nuclear technologies. The purpose of this brochure is to provide the reader with a brief summary of Sandia's technical capabilities, test facilities, and example programs that relate to military and civilian objectives in space. Sandia is interested in forming partnerships with industry and government

  6. Space Station Freedom power - A reliability, availability, and maintainability assessment of the proposed Space Station Freedom electric power system (United States)

    Turnquist, S. R.; Twombly, M.; Hoffman, D.


    A preliminary reliability, availability, and maintainability (RAM) analysis of the proposed Space Station Freedom electric power system (EPS) was performed using the unit reliability, availability, and maintainability (UNIRAM) analysis methodology. Orbital replacement units (ORUs) having the most significant impact on EPS availability measures were identified. Also, the sensitivity of the EPS to variations in ORU RAM data was evaluated for each ORU. Estimates were made of average EPS power output levels and availability of power to the core area of the space station. The results of assessments of the availability of EPS power and power to load distribution points in the space stations are given. Some highlights of continuing studies being performed to understand EPS availability considerations are presented.

  7. Status of NASA's Stirling Space Power Converter Program (United States)

    Dudenhoefer, James E.; Winter, Jerry M.


    An overview is presented of the NASA-Lewis Free-Piston Stirling Space Power Convertor Technology Program. The goal is to develop the technology base needed to meet the long duration, high capacity power requirements for future NASA space initiatives. Efforts are focused upon increasing system power output and system thermal and electric energy conversion efficiency at least fivefold over current SP-100 technology, and on achieving systems that are compatible with space nuclear reactors. Stirling experience in space and progress toward 1050 and 1300 K Stirling Space Power Converters is discussed. Fabrication is nearly completed for the 1050 K Component Test Power Converters (CTPC); results of motoring tests of cold end (525 K), are presented. The success of these and future designs is dependent upon supporting research and technology efforts including heat pipes, bearings, superalloy joining technologies, high efficiency alternators, life and reliability testing and predictive methodologies. An update is provided of progress in some of these technologies leading off with a discussion of free-piston Stirling experience in space.

  8. Beamed microwave power transmission and its application to space (United States)

    Brown, William C.; Eves, E. E.


    The general principles and special components of beamed microwave power transmission systems are outlined and their application to the space program are discussed. The beamed system is defined as starting with a dc source of power at the transmitting end, converting it to a microwave beam for transmission through space, and ending with the dc power output at the receiving end. An experimentally measured and certified dc-to-dc efficiency of 54 percent has been achieved, using this definition. The application discussed is that of a LEO to GEO transportation system that depends upon vehicles propelled by electric thrusters whose power is supplied by a microwave beam originating at the earth's surface. The advantages of the all-electronic system over a chemically propelled system are enumerated. The principles of space propulsion, particularly as they relate to electric propulsion, are outlined. Key components of the system and environmental considerations are discussed.

  9. The outlook for application of powerful nuclear thermionic reactor - powered space electric jet propulsion engines

    Energy Technology Data Exchange (ETDEWEB)

    Semyonov, Y.P.; Bakanov, Y.A.; Synyavsky, V.V.; Yuditsky, V.D. [Rocket-Space Corp. `Energia`, Moscow (Russian Federation)


    This paper summarizes main study results for application of powerful space electric jet propulsion unit (EJPUs) which is powered by Nuclear Thermionic Power Unit (NTPU). They are combined in Nuclear Power/Propulsion Unit (NPPU) which serves as means of spacecraft equipment power supply and spacecraft movement. Problems the paper deals with are the following: information satellites delivery and their on-orbit power supply during 10-15 years, removal of especially hazardous nuclear wastes, mining of asteroid resources and others. Evaluations on power/time/mass relationship for this type of mission are given. EJPU parameters are compatible with Russian existent or being under development launch vehicle. (author)

  10. ``Bimodal'' NTR and LANTR propulsion for human missions to Mars/Phobos (United States)

    Borowski, Stanley K.; Dudzinski, Leonard A.; McGuire, Melissa L.


    The nuclear thermal rocket (NTR) is one of the leading propulsion options for future human missions to Mars due to its high specific impulse (Isp ~850-1000 s) and attractive engine thrust-to-weight ratio (~3-10). Because only a miniscule amount of enriched uranium-235 fuel is consumed in a NTR during the primary propulsion maneuvers of a typical Mars mission, engines configured for both propulsive thrust and modest power generation (referred to as ``bimodal'' operation) provide the basis for a robust, ``power-rich'' stage enabling propulsive Mars capture and reuse capability. A family of modular ``bimodal'' NTR (BNTR) vehicles are described which utilize a common ``core'' stage powered by three 66.7 kN (~15 klbf) BNTRs that produce 50 kWe of total electrical power for crew life support, an active refrigeration/reliquification system for long term, ``zero-boiloff'' liquid hydrogen (LH2) storage, and high data rate communications. Compared to other propulsion options, a Mars mission architecture using BNTR transfer vehicles requires fewer transportation system elements which reduces mission mass, cost and risk because of simplified space operations. For difficult Mars options, such as a Phobos rendezvous and sample return mission, volume (not mass) constraints limit the performance of the ``all LH2'' BNTR stage. The use of ``LOX-augmented'' NTR (LANTR) engines, operating at a modest oxygen-to-hydrogen (O/H) mixture ratio (MR) of 0.5, helps to increase ``bulk'' propellant density and total thrust during the trans-Mars injection (TMI) burn. On all subsequent burns, the bimodal LANTR engines operate on LH2 only (MR=0) to maximize vehicle performance while staying within the mass limits of two ~80 t ``Magnum'' heavy lift launch vehicles (HLLVs).

  11. An Approach to Autonomous Control for Space Nuclear Power Systems

    Energy Technology Data Exchange (ETDEWEB)

    Wood, Richard Thomas [ORNL; Upadhyaya, Belle R. [University of Tennessee, Knoxville (UTK)


    Under Project Prometheus, the National Aeronautics and Space Administration (NASA) investigated deep space missions that would utilize space nuclear power systems (SNPSs) to provide energy for propulsion and spacecraft power. The initial study involved the Jupiter Icy Moons Orbiter (JIMO), which was proposed to conduct in-depth studies of three Jovian moons. Current radioisotope thermoelectric generator (RTG) and solar power systems cannot meet expected mission power demands, which include propulsion, scientific instrument packages, and communications. Historically, RTGs have provided long-lived, highly reliable, low-power-level systems. Solar power systems can provide much greater levels of power, but power density levels decrease dramatically at {approx} 1.5 astronomical units (AU) and beyond. Alternatively, an SNPS can supply high-sustained power for space applications that is both reliable and mass efficient. Terrestrial nuclear reactors employ varying degrees of human control and decision-making for operations and benefit from periodic human interaction for maintenance. In contrast, the control system of an SNPS must be able to provide continuous operatio for the mission duration with limited immediate human interaction and no opportunity for hardware maintenance or sensor calibration. In effect, the SNPS control system must be able to independently operate the power plant while maintaining power production even when subject to off-normal events and component failure. This capability is critical because it will not be possible to rely upon continuous, immediate human interaction for control due to communications delays and periods of planetary occlusion. In addition, uncertainties, rare events, and component degradation combine with the aforementioned inaccessibility and unattended operation to pose unique challenges that an SNPS control system must accommodate. Autonomous control is needed to address these challenges and optimize the reactor control design.

  12. High-Power Electron Accelerators for Space (and other) Applications

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Dinh Cong [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lewellen, John W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)


    This is a presentation on high-power electron accelerators for space and other applications. The main points covered are: electron beams for space applications, new designs of RF accelerators, high-power HEMT testing, and battery design. In summary, we have considered a concept of 1-MeV electron accelerator that can operate up to several seconds. This concept can be extended to higher energy to produce higher beam power. Going to higher beam energy requires adding more cavities and solid-state HEMT RF power devices. The commercial HEMT have been tested for frequency response and RF output power (up to 420 W). And finally, we are testing these HEMT into a resonant load and planning for an electron beam test in FY17.

  13. High-Power Electron Accelerators for Space (and other) Applications

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Dinh Cong [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lewellen, John W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)


    This is a presentation on high-power electron accelerators for space and other applications. The main points covered are: electron beams for space applications, new designs of RF accelerators, high-power high-electron mobility transistors (HEMT) testing, and Li-ion battery design. In summary, the authors have considered a concept of 1-MeV electron accelerator that can operate up to several seconds. This concept can be extended to higher energy to produce higher beam power. Going to higher beam energy requires adding more cavities and solid-state HEMT RF power devices. The commercial HEMT have been tested for frequency response and RF output power (up to 420 W). Finally, the authors are testing these HEMT into a resonant load and planning for an electron beam test in FY17.

  14. Large Scale Magnetic Fields: Density Power Spectrum in Redshift Space

    Indian Academy of Sciences (India)

    Rajesh Gopal; Shiv K. Sethi


    We compute the density redshift-space power spectrum in the presence of tangled magnetic fields and compare it with existing observations. Our analysis shows that if these magnetic fields originated in the early universe then it is possible to construct models for which the shape of the power spectrum agrees with the large scale slope of the observed power spectrum. However requiring compatibility with observed CMBR anisotropies, the normalization of the power spectrum is too low for magnetic fields to have significant impact on the large scale structure at present. Magnetic fields of a more recent origin generically give density power spectrum ∝ 4 which doesn’t agree with the shape of the observed power spectrum at any scale. Magnetic fields generate curl modes of the velocity field which increase both the quadrupole and hexadecapole of the redshift space power spectrum. For curl modes, the hexadecapole dominates over quadrupole. So the presence of curl modes could be indicated by an anomalously large hexadecapole, which has not yet been computed from observation. It appears difficult to construct models in which tangled magnetic fields could have played a major role in shaping the large scale structure in the present epoch. However if they did, one of the best ways to infer their presence would be from the redshift space effects in the density power spectrum.

  15. Space Solar Power Technology Demonstration for Lunar Polar Applications: Laser-Photovoltaic Wireless Power Transmission (United States)

    Henley, M. W.; Fikes, J. C.; Howell, J.; Mankins, J. C.; Howell, Joe T. (Technical Monitor)


    Space Solar Power technology offers unique benefits for near-term NASA space science missions, which can mature this technology for other future applications. "Laser-Photo-Voltaic Wireless Power Transmission" (Laser-PV WPT) is a technology that uses a laser to beam power to a photovoltaic receiver, which converts the laser's light into electricity. Future Laser-PV WPT systems may beam power from Earth to satellites or large Space Solar Power satellites may beam power to Earth, perhaps supplementing terrestrial solar photo-voltaic receivers. In a near-term scientific mission to the moon, Laser-PV WPT can enable robotic operations in permanently shadowed lunar polar craters, which may contain ice. Ground-based technology demonstrations are proceeding, to mature the technology for this initial application, in the moon's polar regions.

  16. Large space systems technology electronics: Data and power distribution (United States)

    Dunbar, W. G.


    The development of hardware technology and manufacturing techniques required to meet space platform and antenna system needs in the 1980s is discussed. Preliminary designs for manned and automatically assembled space power system cables, connectors, and grounding and bonding materials and techniques are reviewed. Connector concepts, grounding design requirements, and bonding requirements are discussed. The problem of particulate debris contamination for large structure spacecraft is addressed.

  17. Whither Space Power? Forging a Strategy for the New Century (United States)


    to achieve our goal? What should those objectives be? The ever-growing field of literature on space power is full of excellent works that either...information. The spy- thriller nature of the entire NRO program, while rapidly push­ ing technology frontiers, stifled most other space initiatives or elsewhere. 25 May 2007. CNN News Report, Montgomery, Alabama: Police here reported today that anti-Islamic literature and numerous other

  18. Civilian Power from Space in the Early 21st Century

    Energy Technology Data Exchange (ETDEWEB)

    Hyde, R; Ishikawa, M; Wood, L


    If power beamed from space is to be become widely used on Earth in the first half of the 21St century, several thus-far-persistent impediments must be obviated, including threshold effects and problematic aspects of cost, availability, reliability, hazards and environmental impacts. We sketch a generally-applicable route to doing so, noting key enabling technologies and practical features. Likely-essential features of any successful strategy include vigorous, systematic leveraging of all intrinsic features of space-derived power, e.g., addressing marginal, high-value-added markets for electric power in space- and time-agile manners to conveniently provide power-upon-demand, and incrementally ''wedging'' into ever-larger markets with ever more cost-efficient generations and scales of technology. We suggest that no prudent strategic plan will rely upon large-scale, long-term public subsidies--fiscal, regulatory, etc.--with their attendant ''sovereign risks'' and interminable delays, and that plan-essential governmental support likely will be limited to early feasibility demonstrations, provision of threshold technologies and a rational, competition-neutral licensing environment. If salient realities are uniformly respected and accessible technologies are intelligently leveraged, electricity derived from space-sourced power-beams may come into significant civilian use during the latter part of the first quarter of this century, and may become widely used by the half-century point.

  19. Multimegawatt space nuclear power supply, Phase 1 Final report

    Energy Technology Data Exchange (ETDEWEB)


    This Specification establishes the performance, design, development, and test requirements for the Boeing Multimegawatt Space Nuclear Power System (MSNPS). The Boeing Multimegawatt Space Power System is part of the DOE/SDIO Multimegawatt Space Nuclear Power Program. The purpose of this program is to provide a space-based nuclear power system to meet the needs of SDIO missions. The Boeing MSNPS is a category 1 concept which is capable of delivering 10's of MW(e) for 100's of seconds with effluent permitted. A design goal is for the system to have growth or downscale capability for other power system concepts. The growth objective is to meet the category 3 capability of 100's of MW(e) for 100's of seconds, also with effluent permitted. The purpose of this preliminary document is to guide the conceptual design effort throughout the Phase 1 study effort. This document will be updated through out the study. It will thus result in a record of the development of the design effort.

  20. Safety and Nuclear Power Sources for Space Systems (United States)

    Segalas, Corinne C.; Schmidt, George R.


    Nuclear power sources have been used in space applications for decades. They have been used extensively for electrical power production, and their future potential for propulsion has been recognized since the dawn of the spaceflight era. Nuclear power sources offer many advantages in terms of long duration operation and high power densities independent of distance and orientation with respect to the Sun. However, it is also broadly known that use of radioactive materials do carry more risk that must be addressed to ensure safe operation during all phases of the mission, particularly before and during launch into orbit. Almost all of the nuclear-powered missions to date have been flown by the United States and former Soviet Union, but other space-faring nations have recognized its importance for their future missions. Consequently, many in the space community have advocated the development of a broad set of principles that could be applied on an international basis. This paper examines the current guidelines by the major space-faring nations, and suggests a framework primarily based on the U.S. methodology for ensuring reduction of risk, mitigating environmental impact and promoting launch safety.

  1. Terrestrial Applications of Extreme Environment Stirling Space Power Systems (United States)

    Dyson, Rodger. W.


    NASA has been developing power systems capable of long-term operation in extreme environments such as the surface of Venus. This technology can use any external heat source to efficiently provide electrical power and cooling; and it is designed to be extremely efficient and reliable for extended space missions. Terrestrial applications include: use in electric hybrid vehicles; distributed home co-generation/cooling; and quiet recreational vehicle power generation. This technology can reduce environmental emissions, petroleum consumption, and noise while eliminating maintenance and environmental damage from automotive fluids such as oil lubricants and air conditioning coolant. This report will provide an overview of this new technology and its applications.

  2. Thermal control system for Space Station Freedom photovoltaic power module (United States)

    Hacha, Thomas H.; Howard, Laura


    The electric power for Space Station Freedom (SSF) is generated by the solar arrays of the photovoltaic power modules (PVM's) and conditioned, controlled, and distributed by a power management and distribution system. The PVM's are located outboard of the alpha gimbals of SSF. A single-phase thermal control system is being developed to provide thermal control of PVM electrical equipment and energy storage batteries. This system uses ammonia as the coolant and a direct-flow deployable radiator. The description and development status of the PVM thermal control system is presented.

  3. Space-to-Space Power Beaming Enabling High Performance Rapid Geocentric Orbit Transfer (United States)

    Dankanich, John W.; Vassallo, Corinne; Tadge, Megan


    The use of electric propulsion is more prevalent than ever, with industry pursuing all electric orbit transfers. Electric propulsion provides high mass utilization through efficient propellant transfer. However, the transfer times become detrimental as the delta V transitions from near-impulsive to low-thrust. Increasing power and therefore thrust has diminishing returns as the increasing mass of the power system limits the potential acceleration of the spacecraft. By using space-to-space power beaming, the power system can be decoupled from the spacecraft and allow significantly higher spacecraft alpha (W/kg) and therefore enable significantly higher accelerations while maintaining high performance. This project assesses the efficacy of space-to-space power beaming to enable rapid orbit transfer while maintaining high mass utilization. Concept assessment requires integrated techniques for low-thrust orbit transfer steering laws, efficient large-scale rectenna systems, and satellite constellation configuration optimization. This project includes the development of an integrated tool with implementation of IPOPT, Q-Law, and power-beaming models. The results highlight the viability of the concept, limits and paths to infusion, and comparison to state-of-the-art capabilities. The results indicate the viability of power beaming for what may be the only approach for achieving the desired transit times with high specific impulse.

  4. Fuel Cells: Power System Option for Space Research (United States)

    Shaneeth, M.; Mohanty, Surajeet


    Fuel Cells are direct energy conversion devices and, thereby, they deliver electrical energy at very high efficiency levels. Hydrogen and Oxygen gases are electrochemically processed, producing clean electric power with water as the only by product. A typical, Fuel Cell based power system involve a Electrochemical power converter, gas storage and management systems, thermal management systems and relevant control units. While there exists different types of Fuel cells, Proton Exchange Membrane (PEM) Fuel Cells are considered as the most suitable one for portable applications. Generally, Fuel Cells are considered as the primary power system option in space missions requiring high power ( > 5kW) and long durations and also where water is a consumable, such as manned missions. This is primarily due to the advantage that fuel cell based power systems offer, in terms of specific energy. Fuel cells have the potential to attain specific energy > 500Wh/kg, specific power >500W/kg, energy density > 400Whr/L and also power density > 200 W/L. This apart, a fuel cell system operate totally independent of sun light, whereas as battery based system is fully dependent on the same. This uniqueness provides added flexibility and capabilities to the missions and modularity for power system. High power requiring missions involving reusable launch vehicles, manned missions etc are expected to be richly benefited from this. Another potential application of Fuel Cell would be interplanetary exploration. Unpredictable and dusty atmospheres of heavenly bodies limits sun light significantly and there fuel cells of different types, eg, Bio-Fuel Cells, PEMFC, DMFCs would be able to work effectively. Manned or unmanned lunar out post would require continuous power even during extra long lunar nights and high power levels are expected. Regenerative Fuel Cells, a combination of Fuel Cells and Electrolysers, are identified as strong candidate. While application of Fuel Cells in high power

  5. Performance of International Space Station Alpha electric power systems

    Energy Technology Data Exchange (ETDEWEB)

    Hill, R.; Lu, C.Y.; Padhye, V.; Hajela, G.; Hague, L. [Rockwell International, Canoga Park, CA (United States). Rocketdyne Division


    The International Space Station Alpha (ISSA) will be an Earth-orbiting laboratory in space. It will house experimental payloads, distribute resource utilities, and support human habitation for conducting research and science experiments in a microgravity environment. Electrical power is a major utility to support successful achievement of the mission goal. The ISSA United States On-Orbit Segment (USOS) Electric Power System (EPS) power generation capability will vary with orbital parameters, natural and induced environment, and hardware aging/replacement throughout the ISSA life. Power capability will be further restricted by various assembly configurations during ISSA buildup, by various flight attitudes, by shadowing on the solar arrays, by EPS operational constraints, such as pointing accuracy, battery charging, as well as operating voltage setpoints, and by ISSA operational constraints either to avoid long-term solar array shadowing from the adjacent solar array or to accommodate ISSA maneuver during proximity operations with other space vehicles, mating, and departing. Design of the ISSA USOS EPS takes into consideration the various equipment degradation modes, operation constraints, and orbital conditions to make it compatible with the environments and to meet power, lifetime, and performance requirements.

  6. Fresnel Concentrators for Space Solar Power and Solar Thermal Propulsion (United States)

    Bradford, Rodney; Parks, Robert W.; Craig, Harry B. (Technical Monitor)


    Large deployable Fresnel concentrators are applicable to solar thermal propulsion and multiple space solar power generation concepts. These concentrators can be used with thermophotovoltaic, solar thermionic, and solar dynamic conversion systems. Thin polyimide Fresnel lenses and reflectors can provide tailored flux distribution and concentration ratios matched to receiver requirements. Thin, preformed polyimide film structure components assembled into support structures for Fresnel concentrators provide the capability to produce large inflation-deployed concentrator assemblies. The polyimide film is resistant to the space environment and allows large lightweight assemblies to be fabricated that can be compactly stowed for launch. This work addressed design and fabrication of lightweight polyimide film Fresnel concentrators, alternate materials evaluation, and data management functions for space solar power concepts, architectures, and supporting technology development.

  7. Power Absorption by Closely Spaced Point Absorbers in Constrained Conditions

    DEFF Research Database (Denmark)

    De Backer, G.; Vantorre, M.; Beels, C.;


    The performance of an array of closely spaced point absorbers is numerically assessed in a frequency domain model Each point absorber is restricted to the heave mode and is assumed to have its own linear power take-off (PTO) system Unidirectional irregular incident waves are considered, represent......The performance of an array of closely spaced point absorbers is numerically assessed in a frequency domain model Each point absorber is restricted to the heave mode and is assumed to have its own linear power take-off (PTO) system Unidirectional irregular incident waves are considered......, representing the wave climate at Westhinder on the Belgian Continental Shelf The impact of slamming, stroke and force restrictions on the power absorption is evaluated and optimal PTO parameters are determined For multiple bodies optimal control parameters (CP) are not only dependent on the incoming waves...

  8. Programmatic status of NASA's CSTI high capacity power Stirling space power converter program (United States)

    Dudenhoefer, James E.


    An overview is presented of the NASA Lewis Research Center Free-Piston Stirling Space Power Converter Technology Development Program. This work is being conducted under NASA's Civil Space Technology Initiative (CSTI). The goal of the CSTI High Capacity Power element is to develop the technology base needed to meet the long duration, high capacity power requirements for future NASA space initiatives. Efforts are focused upon increasing system thermal and electric energy conversion efficiency at least fivefold over current SP-100 technology, and on achieving systems that are compatible with space nuclear reactors. The status of test activities with the Space Power Research Engine (SPRE) is discussed. Design deficiencies are gradually being corrected and the power converter is now outputting 11.5 kWe at a temperature ratio of 2 (design output is 12.5 kWe). Detail designs were completed for the 1050 K Component Test Power Converter (CTPC). The success of these and future designs is dependent upon supporting research and technology efforts including heat pipes, gas bearings, superalloy joining technologies and high efficiency alternators. An update of progress in these technologies is provided.

  9. Bimodal Galaxies and Bimodality in Globular Cluster Systems

    CERN Document Server

    Forbes, D A


    Various galaxy properties are not continuous over a large range in mass, but rather reveal a remarkable transition or `bimodality' at a stellar mass of 3 x 10^{10} Mo. These properties include colors, stellar populations, Xray emission and mass-to-light ratios. This behavior has been interpreted as the transition from hot to cold flows by Dekel & Birnboim (2005). Here we explore whether globular cluster (GC) systems also reveal a bimodal nature with regard to this critical mass scale. Globular clusters probe star formation at early epochs in the Universe and survive subsequent galaxy mergers and accretions. We use new data from the ACS Virgo Cluster Survey (Peng etal 2005), which provides a homogeneous sample of the GC systems around one hundred Virgo early-type galaxies covering a range of five hundred in galaxy mass. Their classification of the GC color distributions is taken to examine a key quantity -- the number of GCs per unit galaxy luminosity. Below the critical mass, this quantity (called the GC ...

  10. Structural Materials and Fuels for Space Power Plants (United States)

    Bowman, Cheryl; Busby, Jeremy; Porter, Douglas


    A fission reactor combined with Stirling convertor power generation is one promising candidate in on-going Fission Surface Power (FSP) studies for future lunar and Martian bases. There are many challenges for designing and qualifying space-rated nuclear power plants. In order to have an affordable and sustainable program, NASA and DOE designers want to build upon the extensive foundation in nuclear fuels and structural materials. This talk will outline the current Fission Surface Power program and outline baseline design options for a lunar power plant with an emphasis on materials challenges. NASA first organized an Affordable Fission Surface Power System Study Team to establish a reference design that could be scrutinized for technical and fiscal feasibility. Previous papers and presentations have discussed this study process in detail. Considerations for the reference design included that no significant nuclear technology, fuels, or material development were required for near term use. The desire was to build upon terrestrial-derived reactor technology including conventional fuels and materials. Here we will present an overview of the reference design, Figure 1, and examine the materials choices. The system definition included analysis and recommendations for power level and life, plant configuration, shielding approach, reactor type, and power conversion type. It is important to note that this is just one concept undergoing refinement. The design team, however, understands that materials selection and improvement must be an integral part of the system development.

  11. Solitary Dunes under Bimodal Winds (United States)

    Reffet, Erwan; Courrech du Pont, S.; Hersen, P.; Fulchignoni, M.; Douady, S.


    The high resolution and coverage achieved on Mars' surface have detailed lots of sand dunes of various types [1]. Many are reported as barchan or barchanoid dunes and present a diversity of shape ascribed to compound wind regimes, collisions or cementation. This diversity reminds us that aeolian structures are fairly complex. Although dunes have been extensively observed and documented, the conditions of their formation and evolution are still difficult to study because of the long time required for their development and their large length-scale. We developed a laboratory approach using underwater experiments to study the morphology of dunes. This method has been used successfully to reproduce various types of dunes downsized to a few centimeters. Barchan dunes are formed using a unidirectional wind-equivalent regime on a pile of ceramic sand-sized grains [2]. Changing the wind regime to a more complex one reveals other structures. In the case of multiple wind directions star dunes can be observed. A bimodal wind regime, e.g. switching between two distinct directions, over an homogeneous layer of sand leads to transverse, longitudinal or complex compound sandbeds depending on the angle between these wind directions [3]. Here, we apply bimodal wind regimes to isolated patches of sand in order to observe the variation of morphology of the resulting dunes. We present the barchanoid dunes obtained for various angles of bimodal wind and show the transition to the "chestnut” dunes type. We also investigate sudden variations in wind direction over a barchan dune. Therefore, we illustrate how the (not so) simple barchan shape can be affected by a more complex wind regime and give a new insight in understanding dunes on Mars. [1] . [2] Hersen et al. PRL, 2003. [3] Reffet et al. 2008.

  12. Radioisotope Power: A Key Technology for Deep Space Explorations (United States)

    Schmidt, George R.; Sutliff, Thomas J.; Duddzinski, Leonard


    A Radioisotope Power System (RPS) generates power by converting the heat released from the nuclear decay of radioactive isotopes, such as Plutonium-238 (Pu-238), into electricity. First used in space by the U.S. in 1961, these devices have enabled some of the most challenging and exciting space missions in history, including the Pioneer and Voyager probes to the outer solar system; the Apollo lunar surface experiments; the Viking landers; the Ulysses polar orbital mission about the Sun; the Galileo mission to Jupiter; the Cassini mission orbiting Saturn; and the recently launched New Horizons mission to Pluto. Radioisotopes have also served as a versatile heat source for moderating equipment thermal environments on these and many other missions, including the Mars exploration rovers, Spirit and Opportunity. The key advantage of RPS is its ability to operate continuously, independent of orientation and distance relative to the Sun. Radioisotope systems are long-lived, rugged, compact, highly reliable, and relatively insensitive to radiation and other environmental effects. As such, they are ideally suited for missions involving long-lived, autonomous operations in the extreme conditions of space and other planetary bodies. This paper reviews the history of RPS for the U.S. space program. It also describes current development of a new Stirling cycle-based generator that will greatly expand the application of nuclear-powered missions in the future.

  13. Sandwich module prototype progress for space solar power (United States)

    Jaffe, Paul; Hodkin, Jason; Harrington, Forest; Person, Clark; Nurnberger, Michael; Nguyen, Bang; LaCava, Susie; Scheiman, Dave; Stewart, Grant; Han, Andrew; Hettwer, Ethan; Rhoades, Daniel


    Space solar power (SSP) has been broadly defined as the collection of solar energy in space and its wireless transmission for use on earth. This approach potentially gives the benefit of provision of baseload power while avoiding the losses due to the day/night cycle and tropospheric effects that are associated with terrestrial solar power. Proponents have contended that the implementation of such systems could offer energy security, environmental, and technological advantages to those who would undertake their development. Among recent implementations commonly proposed for SSP, the modular symmetrical concentrator (MSC) and other modular concepts have received considerable attention. Each employs an array of modules for performing conversion of concentrated sunlight into microwaves or laser beams for transmission to earth. While prototypes of such modules have been designed and developed previously by several groups, none have been subjected to the challenging conditions inherent to the space environment and the possible solar concentration levels in which an array of modules might be required to operate. The research described herein details our team's efforts in the development of photovoltaic arrays, power electronics, microwave conversion electronics, and antennas for microwave-based "sandwich" module prototypes. The implementation status and testing results of the prototypes are reviewed.

  14. Solid state radioisotopic energy converter for space nuclear power

    Energy Technology Data Exchange (ETDEWEB)

    Brown, P.M. (IsoGen Radioisotopic Research Laboratory, 315 S. McLoughlin Blvd., Oregon City, Oregon 97045 (United States))


    Recent developments in materials technology now make it possible to fabricate nonthermal thin-film radioisotopic energy converters (REC) with a specific power of 24 W/kg and a 10 year working life at 5 to 10 watts. This creates applications never before possible, such as placing the power supply directly on integrated circuit chips. The efficiency of the REC is about 25% which is two to three times greater than the 6 to 8% capabilities of current thermoelectric systems. Radioisotopic energy converters have the potential to meet many future space power requirements for a wide variety of applications with less mass, better efficiency, and less total area than other power conversion options. These benefits result in significant dollar savings over the projected mission lifetime.

  15. Power spectrum with auxiliary fields in de Sitter space

    Energy Technology Data Exchange (ETDEWEB)

    Mohsenzadeh, M. [Islamic Azad University, Department of Physics, Qom Branch, Qom (Iran, Islamic Republic of); Tanhayi, M.R. [Islamic Azad University, Department of Physics, Central Tehran Branch, Tehran (Iran, Islamic Republic of); Yusofi, E. [Islamic Azad University, Department of Physics, Science and Research Ayatollah Amoli Branch, Amol, Mazandaran (Iran, Islamic Republic of)


    We use the auxiliary fields and (excited-) de Sitter solutions to study the standard power spectrum of primordial fluctuations of a scalar field in the early universe. The auxiliary fields are the negative norm solutions of the field equation and as is shown, with a fixed boundary condition, utilizing these states results in a finite power spectrum without any infinity. The power spectrum is determined by the de Sitter solutions up to some corrections and the space-time symmetry is not broken in this point of view. The modulation to the power spectrum is of order ((H)/(Λ)){sup 2}, where H is the Hubble parameter and Λ is the energy scale, e.g., the Planck scale. (orig.)

  16. Advanced thermal management techniques for space power electronics (United States)

    Reyes, Angel Samuel


    Modern electronic systems used in space must be reliable and efficient with thermal management unaffected by outer space constraints. Current thermal management techniques are not sufficient for the increasing waste heat dissipation of novel electronic technologies. Many advanced thermal management techniques have been developed in recent years that have application in high power electronic systems. The benefits and limitations of emerging cooling technologies are discussed. These technologies include: liquid pumped devices, mechanically pumped two-phase cooling, capillary pumped evaporative cooling, and thermoelectric devices. Currently, liquid pumped devices offer the most promising alternative for electronics thermal control.

  17. Space Environment Stability and Physical Properties of New Materials for Space Power and Commercial Applications (United States)

    Hambourger, Paul D.


    To test and evaluate suitability of materials for use in space power systems and related space and commercial applications, and to achieve sufficient understanding of the mechanisms by which, the materials perform in their intended applications. Materials and proposed applications included but were not limited to: Improved anodes for lithium ion batteries, highly-transparent arc-proof solar array coatings, and improved surface materials for solar dynamic concentrators and receivers. Cooperation and interchange of data with industrial companies as appropriate.

  18. Overview of space power electronic's technology under the CSTI High Capacity Power Program (United States)

    Schwarze, Gene E.

    The Civilian Space Technology Initiative (CSTI) is a NASA Program targeted at the development of specific technologies in the areas of transportation, operations and science. Each of these three areas consists of major elements and one of the operation's elements is the High Capacity Power element. The goal of this element is to develop the technology base needed to meet the long duration, high capacity power requirements for future NASA initiatives. The High Capacity Power element is broken down into several subelements that includes energy conversion in the areas of the free piston Stirling power converter and thermoelectrics, thermal management, power management, system diagnostics, and environmental compatibility and system's lifetime. A recent overview of the CSTI High capacity Power element and a description of each of the program's subelements is given by Winter (1989). The goals of the Power Management subelement are twofold. The first is to develop, test, and demonstrate high temperature, radiation-resistant power and control components and circuits that will be needed in the Power Conditioning, Control and Transmission (PCCT) subsystem of a space nuclear power system. The results obtained under this goal will also be applicable to the instrumentation and control subsystem of a space nuclear reactor. These components and circuits must perform reliably for lifetimes of 7-10 years. The second goal is to develop analytical models for use in computer simulations of candidate PCCT subsystems. Circuits which will be required for a specific PCCT subsystem will be designed and built to demonstrate their performance and, also, to validate the analytical models and simulations. The tasks under the Power Management subelement will now be described in terms of objectives, approach and present status of work.

  19. Overview of space power electronic's technology under the CSTI High Capacity Power Program (United States)

    Schwarze, Gene E.


    The Civilian Space Technology Initiative (CSTI) is a NASA Program targeted at the development of specific technologies in the areas of transportation, operations and science. Each of these three areas consists of major elements and one of the operation's elements is the High Capacity Power element. The goal of this element is to develop the technology base needed to meet the long duration, high capacity power requirements for future NASA initiatives. The High Capacity Power element is broken down into several subelements that includes energy conversion in the areas of the free piston Stirling power converter and thermoelectrics, thermal management, power management, system diagnostics, and environmental compatibility and system's lifetime. A recent overview of the CSTI High capacity Power element and a description of each of the program's subelements is given by Winter (1989). The goals of the Power Management subelement are twofold. The first is to develop, test, and demonstrate high temperature, radiation-resistant power and control components and circuits that will be needed in the Power Conditioning, Control and Transmission (PCCT) subsystem of a space nuclear power system. The results obtained under this goal will also be applicable to the instrumentation and control subsystem of a space nuclear reactor. These components and circuits must perform reliably for lifetimes of 7-10 years. The second goal is to develop analytical models for use in computer simulations of candidate PCCT subsystems. Circuits which will be required for a specific PCCT subsystem will be designed and built to demonstrate their performance and, also, to validate the analytical models and simulations. The tasks under the Power Management subelement will now be described in terms of objectives, approach and present status of work.

  20. Dune formation under bimodal winds. (United States)

    Parteli, Eric J R; Durán, Orencio; Tsoar, Haim; Schwämmle, Veit; Herrmann, Hans J


    The study of dune morphology represents a valuable tool in the investigation of planetary wind systems--the primary factor controlling the dune shape is the wind directionality. However, our understanding of dune formation is still limited to the simplest situation of unidirectional winds: There is no model that solves the equations of sand transport under the most common situation of seasonally varying wind directions. Here we present the calculation of sand transport under bimodal winds using a dune model that is extended to account for more than one wind direction. Our calculations show that dunes align longitudinally to the resultant wind trend if the angle(w) between the wind directions is larger than 90 degrees. Under high sand availability, linear seif dunes are obtained, the intriguing meandering shape of which is found to be controlled by the dune height and by the time the wind lasts at each one of the two wind directions. Unusual dune shapes including the "wedge dunes" observed on Mars appear within a wide spectrum of bimodal dune morphologies under low sand availability.

  1. Laser-powered MHD generators for space application (United States)

    Jalufka, N. W.


    Magnetohydrodynamic (MHD) energy conversion systems of the pulsed laser-supported detonation (LSD) wave, plasma MHD, and liquid-metal MHD (LMMHD) types are assessed for their potential as space-based laser-to-electrical power converters. These systems offer several advantages as energy converters relative to the present chemical, nuclear, and solar devices, including high conversion efficiency, simple design, high-temperature operation, high power density, and high reliability. Of these systems, the Brayton cycle liquid-metal MHD system appears to be the most attractive. The LMMHD technology base is well established for terrestrial applications, particularly with regard to the generator, mixer, and other system components. However, further research is required to extend this technology base to space applications and to establish the technology required to couple the laser energy into the system most efficiently. Continued research on each of the three system types is recommended.

  2. Dynamic Computer Model of a Stirling Space Nuclear Power System (United States)


    Appendix E. 42 61 5. Heat Rejection System The liquid metal heat rejection loop feeds through the coolers of the Stirling converters to...load-following system , where load is based on the heat transferred and rejected by the Stirling heater and cooler to the working gas. A change in one...U.S.N.A. --- Trident Scholar project report; no. 345 (2006) DYNAMIC COMPUTER MODEL OF A STIRLING SPACE NUCLEAR POWER SYSTEM by

  3. Space Station Freedom electric power system photovoltaic power module integrated launch package (United States)

    Nathanson, Theodore H.; Clemens, Donald D.; Spatz, Raymond R.; Kirch, Luke A.


    The launch of the Space Station Freedom solar power module requires a weight efficient structure that will include large components within the limited load capacity of the Space Shuttle cargo bay. The design iterations to meet these requirements have evolved from a proposal concept featuring a separate cradle and integrated equipment assembly (IEA), to a package that interfaces directly with the Shuttle. Size, weight, and cost have been reduced as a result.

  4. Space Solar Power Technology Demonstration for Lunar Polar Applications (United States)

    Henley, M. W.; Fikes, J. C.; Howell, J.; Mankins, J. C.


    A solar power generation station on a mountaintop near the moon's North or South pole can receive sunlight 708 hours per lunar day, for continuous power generation. Power can be beamed from this station over long distances using a laser-based wireless power transmission system and a photo-voltaic receiver. This beamed energy can provide warmth, electricity, and illumination for a robotic rover to perform scientific experiments in cold, dark craters where no other power source is practical. Radio-frequency power transmission may also be demonstrated in lunar polar applications to locate and recover sub-surface deposits of volatile material, such as water ice. High circular polarization ratios observered in data from Clementine spacecraft and Arecibo radar reflections from the moon's South pole suggest that water ice is indeed present in certain lunar polar craters. Data from the Lunar Prospector spacecraft's epi-thermal neutron spectrometer also indicate that hydrogen is present at the moon's poles. Space Solar Power technology enables investigation of these craters, which may contain a billion-year-old stratigraphic record of tremendous scientific value. Layers of ice, preserved at the moon's poles, could help us determine the sequence and composition of comet impacts on the moon. Such ice deposits may even include distinct strata deposited by secondary ejecta following significant Earth (ocean) impacts, linked to major extinctions of life on Earth. Ice resources at the moon's poles could provide water and air for human exploration and development of space as well as rocket propellant for future space transportation. Technologies demonstrated and matured via lunar polar applications can also be used in other NASA science missions (Valles Marineris, Phobos, Deimos, Mercury's poles, asteroids, etc.) and in future large-scale SSP systems to beam energy from space to Earth. Ground-based technology demonstrations are proceeding to mature the technology for such a near

  5. Refractory alloy technology for space nuclear power applications

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, R.H. Jr.; Hoffman, E.E. (eds.)


    Purpose of this symposium is twofold: (1) to review and document the status of refractory alloy technology for structural and fuel-cladding applications in space nuclear power systems, and (2) to identify and document the refractory alloy research and development needs for the SP-100 Program in both the short and the long term. In this symposium, an effort was made to recapture the space reactor refractory alloy technology that was cut off in midstream around 1973 when the national space nuclear reactor program began in the early 1960s, was terminated. The six technical areas covered in the program are compatibility, processing and production, welding and component fabrication, mechanical and physical properties, effects of irradiation, and machinability. The refractory alloys considered are niobium, molybdenum, tantalum, and tungsten. Thirteen of the 14 pages have been abstracted separately. The remaining paper summarizes key needs for further R and D on refractory alloys. (DLC)

  6. High Power Combline Filter for Deep Space Applications

    Directory of Open Access Journals (Sweden)

    A. V. G. Subramanyam


    Full Text Available An S-band, compact, high power filter, for use in the Mars Orbiter Mission (MOM of Indian Space Research Organization (ISRO, has been designed and tested for multipaction. The telemetry, tracking, and commanding (TT&C transponder of MOM is required to handle continuous RF power of 200 W in the telemetry path besides simultaneously maintaining an isolation of greater than 145 dBc to its sensitive telecommand path. This is accomplished with the help of a complex diplexer, requiring high power, high rejection transmit path filter, and a low power receive path filter. To reduce the complexity in the multipaction-free design and testing, the transmit path filter of the diplexer is split into a low rejection filter integral to the diplexer and an external high rejection filter. This paper highlights the design and space qualification phases of this high rejection filter. Multipaction test results with 6 dB margin are also presented. Major concerns of this filter design are isolation, insertion loss, and multipaction. Mission performance of the on-board filter is normal.

  7. Power management and distribution equipment developed for space applications (United States)

    Thornton, R. D.

    Some of the current developments in the area of dc power switching and conversion equipment are described for Space Station Freedom. The equipment includes 120-Vdc remote power controllers (RPCs) rated at 1 kW, 5 kW, and 15 kW; 25-kW and 50-kW remote bus isolators (RBIs), both uni- and bi-directional; a 1-kW 120-Vdc/28-Vdc converter; and a 250-Adc differential fault protection module. Most of this equipment was designed to allow communication with a power system controller via a full MIL-STD-1553B data bus interface. The standard interface/data acquisition card developed for the described hardware allows remote control of the equipment as well as monitoring of system loads and voltages.

  8. NERVA-Derived Concept for a Bimodal Nuclear Thermal Rocket (United States)

    Fusselman, Steven P.; Borowski, Stanley K.; Frye, Patrick E.; Gunn, Stanley V.; Morrison, Calvin Q.


    The Nuclear Thermal Rocket is an enabling technology for human exploration missions. The "bimodal" NTR (BNTR) provides a novel approach to meeting both propulsion and power requirements of future manned and robotic missions. The purpose of this study was to evaluate tie-tube cooling configurations, NTR performance, Brayton cycle performance, and LOX-Augmented NTR (LANTR) feasibility to arrive at a point of departure BNTR configuration for subsequent system definition.

  9. BSA adsorption on bimodal PEO brushes

    NARCIS (Netherlands)

    Bosker, WTE; Iakovlev, PA; Norde, W; Stuart, Martien A. Cohen


    BSA adsorption onto bimodal PEO brushes at a solid surface was measured using optical reflectometry. Bimodal brushes consist of long (N = 770) and short (N = 48) PEO chains and were prepared on PS surfaces, applying mixtures of PS29-PEO48 and PS37-PEO770 block copolymers and using the Langmuir-Blodg

  10. BSA adsorption on bimodal PEO brushes

    NARCIS (Netherlands)

    Bosker, W.T.E.; Iakovlev, P.A.; Norde, W.; Cohen Stuart, M.A.


    BSA adsorption onto bimodal PEO brushes at a solid surface was measured using optical reflectometry. Bimodal brushes consist of long (N=770) and short (N=48) PEO chains and were prepared on PS surfaces, applying mixtures of PS 29-PEO48 and PS37-PEO770 block copolymers and using the Langmuir-Blodgett

  11. Space Solar Power Satellite Systems, Modern Small Satellites, and Space Rectenna (United States)

    Bergsrud, Corey Alexis Marvin

    Space solar power satellite (SSPS) systems is the concept of placing large satellite into geostationary Earth orbit (GEO) to harvest and convert massive amounts of solar energy into microwave energy, and to transmit the microwaves to a rectifying antenna (rectenna) array on Earth. The rectenna array captures and converts the microwave power into usable power that is injected into the terrestrial electric grid for use. This work approached the microwave power beam as an additional source of power (with solar) for lower orbiting satellites. Assuming the concept of retrodirectivity, a GEO-SSPS antenna array system tracks and delivers microwave power to lower orbiting satellites. The lower orbiting satellites are equipped with a stacked photovoltaic (PV)/rectenna array hybrid power generation unit (HPGU) in order to harvest solar and/or microwave energy for on-board use during orbit. The area, and mass of the PV array part of the HPGU was reduced at about 32% beginning-of-life power in order to achieve the spacecraft power requirements. The HPGU proved to offer a mass decrease in the PGU, and an increase in mission life due to longer living component life of the rectenna array. Moreover, greater mission flexibility is achieved through a track and power delivery concept. To validate the potential advantages offered by a HPGU, a mission concept was presented that utilizes modern small satellites as technology demonstrators. During launch, a smaller power receiving "daughter" satellite sits inside a larger power transmitting "mother" satellite. Once separated from the launch vehicle the daughter satellite is ejected away from the mother satellite, and each satellite deploys its respective power transmitting or power receiving hardware's for experimentation. The concept of close proximity mission operations between the satellites is considered. To validate the technology of the space rectenna array part of the HPGU, six milestones were completed in the design. The first

  12. Space, time, error, and power optimization of image compression transforms (United States)

    Schmalz, Mark S.; Ritter, Gerhard X.; Caimi, Frank M.


    The implementation of an image compression transform on one or more small, embedded processors typically involves stringent constraints on power consumption and form factor. Traditional methods of optimizing compression algorithm performance typically emphasize joint minimization of space and time complexity, often without significant consideration of arithmetic accuracy or power consumption. However, small autonomous imaging platforms typically require joint optimization of space, time, error (or accuracy), and power (STEP) parameters, which the authors call STEP optimization. In response to implementational constraints on space and power consumption, the authors have developed systems and techniques for STEP optimization that are based on recent research in VLSI circuit design, as well as extensive previous work in system optimization. Building on the authors' previous research in embedded processors as well as adaptive or reconfigurable computing, it is possible to produce system-independent STEP optimization that can be customized for a given set of system-specific constraints. This approach is particularly useful when algorithms for image and signal processing (ISP) computer vision (CV), or automated target recognition (ATR), expressed in a machine- independent notation, are mapped to one or more heterogeneous processors (e.g., digital signal processors or DSPs, SIMD mesh processors, or reconfigurable logic). Following a theoretical summary, this paper illustrates various STEP optimization techniques via case studies, for example, real-time compression of underwater imagery on board an autonomous vehicle. Optimization algorithms are taken from the literature, and error profiling/analysis methodologies developed in the authors' previous research are employed. This yields a more rigorous basis for the simulation and evaluation of compression algorithms on a wide variety of hardware models. In this study, image algebra is employed as the notation of choice

  13. Systems definition space-based power conversion systems. [for satellite power transmission to earth (United States)


    Potential space-located systems for the generation of electrical power for use on Earth are discussed and include: (1) systems producing electrical power from solar energy; (2) systems producing electrical power from nuclear reactors; and (3) systems for augmenting ground-based solar power plants by orbital sunlight reflectors. Systems (1) and (2) would utilize a microwave beam system to transmit their output to Earth. Configurations implementing these concepts were developed through an optimization process intended to yield the lowest cost for each. A complete program was developed for each concept, identifying required production rates, quantities of launches, required facilities, etc. Each program was costed in order to provide the electric power cost appropriate to each concept.

  14. Protoflight photovoltaic power module system-level tests in the space power facility (United States)

    Rivera, Juan C.; Kirch, Luke A.


    Work Package Four, which includes the NASA-Lewis and Rocketdyne, has selected an approach for the Space Station Freedom Photovoltaic (PV) Power Module flight certification that combines system level qualification and acceptance testing in the thermal vacuum environment: The protoflight vehicle approach. This approach maximizes ground test verification to assure system level performance and to minimize risk of on-orbit failures. The preliminary plans for system level thermal vacuum environmental testing of the protoflight PV Power Module in the NASA-Lewis Space Power Facility (SPF), are addressed. Details of the facility modifications to refurbish SPF, after 13 years of downtime, are briefly discussed. The results of an evaluation of the effectiveness of system level environmental testing in screening out incipient part and workmanship defects and unique failure modes are discussed. Preliminary test objectives, test hardware configurations, test support equipment, and operations are presented.

  15. Operational environments for electrical power wiring on NASA space systems (United States)

    Stavnes, Mark W.; Hammoud, Ahmad N.; Bercaw, Robert W.


    Electrical wiring systems are used extensively on NASA space systems for power management and distribution, control and command, and data transmission. The reliability of these systems when exposed to the harsh environments of space is very critical to mission success and crew safety. Failures have been reported both on the ground and in flight due to arc tracking in the wiring harnesses, made possible by insulation degradation. This report was written as part of a NASA Office of Safety and Mission Assurance (Code Q) program to identify and characterize wiring systems in terms of their potential use in aerospace vehicles. The goal of the program is to provide the information and guidance needed to develop and qualify reliable, safe, lightweight wiring systems, which are resistant to arc tracking and suitable for use in space power applications. This report identifies the environments in which NASA spacecraft will operate, and determines the specific NASA testing requirements. A summary of related test programs is also given in this report. This data will be valuable to spacecraft designers in determining the best wiring constructions for the various NASA applications.

  16. A logistics model for large space power systems (United States)

    Koelle, H. H.

    Space Power Systems (SPS) have to overcome two hurdles: (1) to find an attractive design, manufacturing and assembly concept and (2) to have available a space transportation system that can provide economical logistic support during the construction and operational phases. An initial system feasibility study, some five years ago, was based on a reference system that used terrestrial resources only and was based partially on electric propulsion systems. The conclusion was: it is feasible but not yet economically competitive with other options. This study is based on terrestrial and extraterrestrial resources and on chemical (LH 2/LOX) propulsion systems. These engines are available from the Space Shuttle production line and require small changes only. Other so-called advanced propulsion systems investigated did not prove economically superior if lunar LOX is available! We assume that a Shuttle derived Heavy Lift Launch Vehicle (HLLV) will become available around the turn of the century and that this will be used to establish a research base on the lunar surface. This lunar base has the potential to grow into a lunar factory producing LOX and construction materials for supporting among other projects also the construction of space power systems in geostationary orbit. A model was developed to simulate the logistics support of such an operation for a 50-year life cycle. After 50 years 111 SPS units with 5 GW each and an availability of 90% will produce 100 × 5 = 500 GW. The model comprises 60 equations and requires 29 assumptions of the parameter involved. 60-state variables calculated with the 60 equations mentioned above are given on an annual basis and as averages for the 50-year life cycle. Recycling of defective parts in geostationary orbit is one of the features of the model. The state-of-the-art with respect to SPS technology is introduced as a variable Mg mass/MW electric power delivered. If the space manufacturing facility, a maintenance and repair facility

  17. The Integrated Solar Upper Stage engine ground demonstration power management and distribution subsystem design (United States)

    Baez, Anastacio N.; Kimnach, Greg L.


    The National Aeronautics and Space Administration (NASA), the Air Force Phillips Laboratory (PL), and the Defense Special Weapons Agency (DSWA) in a joint effort are developing technologies for a solar bimodal system. A solar bimodal system combines thermal propulsion and electric power generation in a single integrated system. A spacecraft Integrated Solar Upper Stage (ISUS) bimodal system combines orbital transfer propulsion, electric power generation, and on-board propulsion into one overall system. A key benefit of such integrated system is the augmentation of payload to spacecraft mass ratio thus resulting in lower launch vehicle requirements. Scaling down to smaller launch vehicles increases space access by reducing overall mission cost. The NASA/PL/DSWA ISUS program is concentrating efforts on a near-term ground test demonstration of the bimodal concept. A successful ground demonstration of the ISUS various technologies will enable a full system flight demonstration of the bimodal concept. NASA Lewis Research Center in Cleveland Ohio will be the site for the engine ground demonstrator (EGD). The ISUS bimodal system uses solar concentrators to focus solar energy into an integrated receiver, absorber, and converter (RAC) power plant. The power plant main body is a graphite blackbody that stores thermal energy within a cavity in its main core. During the propulsion phase of the bimodal system a propellant flows into the graphite main core and is distributed uniformly through axial flow channels in the heated cavity. The blackbody core heats the propellant that is then discharged into an output tube thus creating thrust. An array of thermionic generators encircles the graphite core cavity and provides electrical energy conversion functions during the power generation phase. The power management and distribution subsystem's main functions are to condition raw electrical power generated by the RAC power plant and deliver it to the spacecraft payloads. This paper

  18. Emerging Space Powers The New Space Programs of Asia, the Middle East, and South America

    CERN Document Server

    Harvey, Brian; Pirard, Théo


    This work introduces the important emerging space powers of the world. Brian Harvey describes the origins of the Japanese space program, from rocket designs based on WW II German U-boats to tiny solid fuel 'pencil' rockets, which led to the launch of the first Japanese satellite in 1970. The next two chapters relate how Japan expanded its space program, developing small satellites into astronomical observatories and sending missions to the Moon, Mars, comet Halley, and asteroids. Chapter 4 describes how India's Vikram Sarabhai developed a sounding rocket program in the 1960s. The following chapter describes the expansion of the Indian space program. Chapter 6 relates how the Indian space program is looking ahead to the success of the moon probe Chandrayan, due to launch in 2008, and its first manned launching in 2014. Chapters 7, 8, and 9 demonstrate how, in Iran, communications and remote sensing drive space technology. Chapter 10 outlines Brazil's road to space, begun in the mid-1960's with the launch of th...

  19. Power system monitoring and source control of the Space Station Freedom DC power system testbed (United States)

    Kimnach, Greg L.; Baez, Anastacio N.


    Unlike a terrestrial electric utility which can purchase power from a neighboring utility, the Space Station Freedom (SSF) has strictly limited energy resources; as a result, source control, system monitoring, system protection, and load management are essential to the safe and efficient operation of the SSF Electric Power System (EPS). These functions are being evaluated in the DC Power Management and Distribution (PMAD) Testbed which NASA LeRC has developed at the Power System Facility (PSF) located in Cleveland, Ohio. The testbed is an ideal platform to develop, integrate, and verify power system monitoring and control algorithms. State Estimation (SE) is a monitoring tool used extensively in terrestrial electric utilities to ensure safe power system operation. It uses redundant system information to calculate the actual state of the EPS, to isolate faulty sensors, to determine source operating points, to verify faults detected by subsidiary controllers, and to identify high impedance faults. Source control and monitoring safeguard the power generation and storage subsystems and ensure that the power system operates within safe limits while satisfying user demands with minimal interruptions. System monitoring functions, in coordination with hardware implemented schemes, provide for a complete fault protection system. The objective of this paper is to overview the development and integration of the state estimator and the source control algorithms.

  20. High power density alkaline fuel cell technology for MMW space burst power (United States)

    Preston, J. Lawrence, Jr.; Trocciola, John C.; Wertheim, Ronald J.

    The use of advanced alkaline regenerative fuel cell energy storage systems to provide 10's to 100's of MWe of sprint (burst) power for 100's of seconds per orbit of SDI weapons platform was studied. Recharge power is supplied by a multimegawatt space based nuclear power system. Regenerative fuel cell energy storage systems offer the potential for significant platform mass reduction by reducing the size and mass of the nuclear power source required. This is because the reactor can be sized for the smaller average power level for the energy storage system, rather than the sprint power level. The regenerative fuel cell is a particularly attractive energy storage device because the fuel cell is essentially a static power conversion device, which results in excellent platform stability for weapon pointing and tracking. Based upon the detailed point design and conceptual layout, the alkaline regenerative fuel cell energy storage system is an attractive choice for integration with a nuclear thermionic system for providing multimegawatt burst power and multi orbit capability.

  1. Thermal energy storage for a space solar dynamic power system (United States)

    Faget, N. M.; Fraser, W. M., Jr.; Simon, W. E.


    In the past, NASA has employed solar photovoltaic devices for long-duration missions. Thus, the Skylab system has operated with a silicon photovoltaic array and a nickel-cadmium electrochemical system energy storage system. Difficulties regarding the employment of such a system for the larger power requirements of the Space Station are related to a low orbit system efficiency and the large weight of the battery. For this reason the employment of a solar dynamic power system (SDPS) has been considered. The primary components of an SDPS include a concentrating mirror, a heat receiver, a thermal energy storage (TES) system, a thermodynamic heat engine, an alternator, and a heat rejection system. The heat-engine types under consideration are a Brayton cycle engine, an organic Rankine cycle engine, and a free-piston/linear-alternator Stirling cycle engine. Attention is given to a system description, TES integration concepts, and a TES technology assessment.

  2. Performance/Power Space Exploration for Binary64 Division Units

    DEFF Research Database (Denmark)

    Nannarelli, Alberto


    The digit-recurrence division algorithm is used in several high-performance processors because it provides good tradeoffs in terms of latency, area and power dissipation. In this work we develop a minimally redundant radix-8 divider for binary64 (double-precision) aiming at obtaining better energy...... efficiency in the performance-per-watt space. The results show that the radix-8 divider, when compared to radix-4 and radix-16 units, requires less energy to complete a division for high clock rates....

  3. Millimeter-Wave Wireless Power Transfer Technology for Space Applications (United States)

    Chattopadhyay, Goutam; Manohara, Harish; Mojarradi, Mohammad M.; Vo, Tuan A.; Mojarradi, Hadi; Bae, Sam Y.; Marzwell, Neville


    In this paper we present a new compact, scalable, and low cost technology for efficient receiving of power using RF waves at 94 GHz. This technology employs a highly innovative array of slot antennas that is integrated on substrate composed of gold (Au), silicon (Si), and silicon dioxide (SiO2) layers. The length of the slots and spacing between them are optimized for a highly efficient beam through a 3-D electromagnetic simulation process. Antenna simulation results shows a good beam profile with very low side lobe levels and better than 93% antenna efficiency.

  4. Design of space-type electronic power transformers (United States)

    Ahearn, J. F.; Lagadinos, J. C.


    Both open and encapsulated varieties of high reliability, low weight, and high efficiency moderate and high voltage transformers were investigated to determine the advantages and limitations of their construction in the ranges of power and voltage required for operation in the hard vacuum environment of space. Topics covered include: (1) selection of the core material; (2) preliminary calculation of core dimensions; (3) selection of insulating materials including magnet wire insulation, coil forms, and layer and interwinding insulation; (4) coil design; (5) calculation of copper losses, core losses and efficiency; (6) calculation of temperature rise; and (7) optimization of design with changes in core selection or coil design as required to meet specifications.

  5. Small Stirling dynamic isotope power system for robotic space missions (United States)

    Bents, D. J.


    The design of a multihundred-watt Dynamic Isotope Power System (DIPS), based on the U.S. Department of Energy (DOE) General Purpose Heat Source (GPHS) and small (multihundred-watt) free-piston Stirling engine (FPSE), is being pursued as a potential lower cost alternative to radioisotope thermoelectric generators (RTG's). The design is targeted at the power needs of future unmanned deep space and planetary surface exploration missions ranging from scientific probes to Space Exploration Initiative precursor missions. Power level for these missions is less than a kilowatt. The incentive for any dynamic system is that it can save fuel and reduce costs and radiological hazard. Unlike DIPS based on turbomachinery conversion (e.g. Brayton), this small Stirling DIPS can be advantageously scaled to multihundred-watt unit size while preserving size and mass competitiveness with RTG's. Stirling conversion extends the competitive range for dynamic systems down to a few hundred watts--a power level not previously considered for dynamic systems. The challenge for Stirling conversion will be to demonstrate reliability and life similar to RTG experience. Since the competitive potential of FPSE as an isotope converter was first identified, work has focused on feasibility of directly integrating GPHS with the Stirling heater head. Thermal modeling of various radiatively coupled heat source/heater head geometries has been performed using data furnished by the developers of FPSE and GPHS. The analysis indicates that, for the 1050 K heater head configurations considered, GPHS fuel clad temperatures remain within acceptable operating limits. Based on these results, preliminary characterizations of multihundred-watt units have been established.

  6. Control of the differential interference contrast in reinjected bimode laser

    CERN Document Server

    Lacot, Eric; Hugon, Olivier; de Chatellus, Hugues Guillet


    We have demonstrated, both theoretically and experimentally, that it is possible to control (i.e., to enhance or cancel) the contrast of the interference pattern appearing in the intensity images obtained with a laser optical feedback imaging (LOFI) setup using a bimode laser. The laser is composed of two coupled orthogonally polarized states that interact (i.e., interfere) through the cross saturation laser dynamics. We created the contrast control by choosing the frequency shift (i.e., the beating frequency) between the feedback electric fields and the intracavity electric fields. We have shown that the interference contrast of the output power modulation of the laser total intensity is independent from the frequency shift and is always maximal. On the other hand, the interference contrast of each polarization state is frequency dependent. We obtained the maximal contrast when the frequency shift was equal to one of the resonance frequencies of the bimode dynamics, and was very low (and almost cancels) for ...

  7. Non-nuclear power sources for deep space

    Energy Technology Data Exchange (ETDEWEB)

    Kennel, E.B.; Tang, C.; Santarius, J.F.


    Electric propulsion and non-nuclear power can be used in tandem as a replacement for the current chemical booster and radioisotope thermoelectric generators now in use for deep space applications (i.e., to the asteroid belt and beyond). In current generation systems, electric propulsion is usually considered to be impractical because of the lack of high power for deep space, and non-nuclear power is thought to be impractical partly due to its high mass. However, when taken in combination, a solar powered electric upper stage can provide ample power and propulsion capability for use in deep space. Radioisotope thermoelectric generator (RTG) systems have generally been selected for missions only when other systems are absolutely unavailable. The disadvantages of radioisotopes include the need for nuclear safety as another dimension of concern in payload integration; the lack of assured availability of plutonium in the post-cold-war world; the enormous cost of plutonium-238; and the system complexity introduced by the need to continuously cool the system during the pre-launch phase. A conservative estimate for the total power for the solar array at beginning of life (BOL) may be in the range of 25 kW in order to provide 500 W continuous power at Jupiter. The availability of {approximately} 25 kW(e) in earth orbit raises the interesting possibility of coupling electric propulsion units to this free electric power. If electric propulsion is used to raise the probe from low-earth-orbit to an earth-escape trajectory, the system could actually save on low-earth orbit mass. Electric propulsion could be used by itself in a spiral trajectory orbit raising maneuver to earth escape velocity, or it could be used in conjunction with a chemical upper stage (either solid rocket or liquid), which would boost the payload to an elliptical orbit. The concept is to begin the Earth-Jupiter trip with a swing-by near the Sun close to the orbit of Venus and perhaps even closer if thermal

  8. Space vehicle electrical power processing distribution and control study. Volume 1: Summary (United States)

    Krausz, A.


    A concept for the processing, distribution, and control of electric power for manned space vehicles and future aircraft is presented. Emphasis is placed on the requirements of the space station and space shuttle configurations. The systems involved are referred to as the processing distribution and control system (PDCS), electrical power system (EPS), and electric power generation system (EPGS).

  9. Space Power Facility-Capabilities for Space Environmental Testing Within a Single Facility (United States)

    Sorge, Richard N.


    The purpose of this paper is to describe the current and near-term environmental test capabilities of the NASA Glenn Research Center's Space Power Facility (SPF) located at Sandusky, Ohio. The paper will present current and near-term capabilities for conducting electromagnetic interference and compatibility testing, base-shake sinusoidal vibration testing, reverberant acoustic testing, and thermal-vacuum testing. The paper will also present modes of transportation, handling, ambient environments, and operations within the facility to conduct those tests. The SPF is in the midst of completing and activating new or refurbished capabilities which, when completed, will provide the ability to conduct most or all required full-scale end-assembly space simulation tests at a single test location. It is envisioned that the capabilities will allow a customer to perform a wide range of space simulation tests in one facility at reasonable cost.

  10. Operational considerations for a crewed nuclear powered space transportation vehicle (United States)

    Borrer, Jerry L.; Hoffman, Stephen J.


    Applying nuclear propulsion technology to human space travel will require new approaches to conducting human operations in space. Due to the remoteness of these types of missions, the crew and their vehicle must be capable of operating independent from Earth-based support. This paper discusses current operational studies which address methods for performing these types of remote and autonomous missions. Methods of managing the hazards to humans who will operate these high-energy nuclear-powered transportation vehicles also is reviewed. Crew training for both normal and contingency operations is considered. Options are evaluated on how best to train crews to operate and maintain the systems associated with a nuclear engine. Methods of maintaining crew proficiency during the long months of space travel are discussed. Vehicle health maintenance also will be a primary concern during these long missions. A discussion is presented on how on-board vehicle health maintenance systems will monitor system trends, identified system weaknesses, and either isolate critical failures or provide the crew with adequate warning of impending problems.

  11. Powering Up With Space-Time Wind Forecasting

    KAUST Repository

    Hering, Amanda S.


    The technology to harvest electricity from wind energy is now advanced enough to make entire cities powered by it a reality. High-quality, short-term forecasts of wind speed are vital to making this a more reliable energy source. Gneiting et al. (2006) have introduced a model for the average wind speed two hours ahead based on both spatial and temporal information. The forecasts produced by this model are accurate, and subject to accuracy, the predictive distribution is sharp, that is, highly concentrated around its center. However, this model is split into nonunique regimes based on the wind direction at an offsite location. This paper both generalizes and improves upon this model by treating wind direction as a circular variable and including it in the model. It is robust in many experiments, such as predicting wind at other locations. We compare this with the more common approach of modeling wind speeds and directions in the Cartesian space and use a skew-t distribution for the errors. The quality of the predictions from all of these models can be more realistically assessed with a loss measure that depends upon the power curve relating wind speed to power output. This proposed loss measure yields more insight into the true value of each models predictions. © 2010 American Statistical Association.

  12. Towards Space Solar Power - Examining Atmospheric Interactions of Power Beams with the HAARP Facility

    CERN Document Server

    Leitgab, M


    In the most common space solar power (SSP) system architectures, solar energy harvested by large satellites in geostationary orbit is transmitted to Earth via microwave radiation. Currently, only limited information about the interactions of microwave beams with energy densities of several tens to hundreds of W/m$^2$ with the different layers of the atmosphere is available. Governmental bodies will likely require detailed investigations of safety and atmospheric effects of microwave power beams before issuing launch licenses for SSP satellite systems. This paper proposes to collect representative and comprehensive data of the interaction of power beams with the atmosphere by extending the infrastructure of the High Frequency Active Auroral Research Program (HAARP) facility in Alaska, USA. Estimates of the transmission infrastructure performance as well as measurement devices and scientific capabilities of possible upgrade scenarios will be discussed. The proposed upgrade of the HAARP facility is expected to d...

  13. Selection of power plant elements for future reactor space electric power systems

    Energy Technology Data Exchange (ETDEWEB)

    Buden, D.; Bennett, G.A.; Copper, K.


    Various types of reactor designs, electric power conversion equipment, and reject-heat systems to be used in nuclear reactor power plants for future space missions were studied. The designs included gas-cooled, liquid-cooled, and heat-pipe reactors. For the power converters, passive types such as thermoelectric and thermionic converters and dynamic types such as Brayton, potassium Rankine, and Stirling cycles were considered. For the radiators, heat pipes for transfer and radiating surface, pumped fluid for heat transfer with fins as the radiating surface, and pumped fluid for heat transfer with heat pipes as the radiating surface were considered. After careful consideration of weights, sizes, reliabilities, safety, and development cost and time, a heat-pipe reactor design, thermoelectric converters, and a heat-pipe radiator for an experimental program were selected.

  14. Summary of space nuclear reactor power systems, 1983--1992

    Energy Technology Data Exchange (ETDEWEB)

    Buden, D.


    This report summarizes major developments in the last ten years which have greatly expanded the space nuclear reactor power systems technology base. In the SP-100 program, after a competition between liquid-metal, gas-cooled, thermionic, and heat pipe reactors integrated with various combinations of thermoelectric thermionic, Brayton, Rankine, and Stirling energy conversion systems, three concepts:were selected for further evaluation. In 1985, the high-temperature (1,350 K), lithium-cooled reactor with thermoelectric conversion was selected for full scale development. Since then, significant progress has been achieved including the demonstration of a 7-y-life uranium nitride fuel pin. Progress on the lithium-cooled reactor with thermoelectrics has progressed from a concept, through a generic flight system design, to the design, development, and testing of specific components. Meanwhile, the USSR in 1987--88 orbited a new generation of nuclear power systems beyond the, thermoelectric plants on the RORSAT satellites. The US has continued to advance its own thermionic fuel element development, concentrating on a multicell fuel element configuration. Experimental work has demonstrated a single cell operating time of about 1 1/2-y. Technology advances have also been made in the Stirling engine; an advanced engine that operates at 1,050 K is ready for testing. Additional concepts have been studied and experiments have been performed on a variety of systems to meet changing needs; such as powers of tens-to-hundreds of megawatts and highly survivable systems of tens-of-kilowatts power.

  15. A Neonatal Bimodal MR-CT Head Template (United States)

    Mohtasebi, Mehrana; Abrishami Moghaddam, Hamid; Grebe, Reinhard; Gity, Masoumeh; Wallois, Fabrice


    Neonatal MR templates are appropriate for brain structural analysis and spatial normalization. However, they do not provide the essential accurate details of cranial bones and fontanels-sutures. Distinctly, CT images provide the best contrast for bone definition and fontanels-sutures. In this paper, we present, for the first time, an approach to create a fully registered bimodal MR-CT head template for neonates with a gestational age of 39 to 42 weeks. Such a template is essential for structural and functional brain studies, which require precise geometry of the head including cranial bones and fontanels-sutures. Due to the special characteristics of the problem (which requires inter-subject inter-modality registration), a two-step intensity-based registration method is proposed to globally and locally align CT images with an available MR template. By applying groupwise registration, the new neonatal CT template is then created in full alignment with the MR template to build a bimodal MR-CT template. The mutual information value between the CT and the MR template is 1.17 which shows their perfect correspondence in the bimodal template. Moreover, the average mutual information value between normalized images and the CT template proposed in this study is 1.24±0.07. Comparing this value with the one reported in a previously published approach (0.63±0.07) demonstrates the better generalization properties of the new created template and the superiority of the proposed method for the creation of CT template in the standard space provided by MR neonatal head template. The neonatal bimodal MR-CT head template is freely downloadable from PMID:28129340

  16. Evidence for a bimodal distribution in human communication. (United States)

    Wu, Ye; Zhou, Changsong; Xiao, Jinghua; Kurths, Jürgen; Schellnhuber, Hans Joachim


    Interacting human activities underlie the patterns of many social, technological, and economic phenomena. Here we present clear empirical evidence from Short Message correspondence that observed human actions are the result of the interplay of three basic ingredients: Poisson initiation of tasks and decision making for task execution in individual humans as well as interaction among individuals. This interplay leads to new types of interevent time distribution, neither completely Poisson nor power-law, but a bimodal combination of them. We show that the events can be separated into independent bursts which are generated by frequent mutual interactions in short times following random initiations of communications in longer times by the individuals. We introduce a minimal model of two interacting priority queues incorporating the three basic ingredients which fits well the distributions using the parameters extracted from the empirical data. The model can also embrace a range of realistic social interacting systems such as e-mail and letter communications when taking the time scale of processing into account. Our findings provide insight into various human activities both at the individual and network level. Our analysis and modeling of bimodal activity in human communication from the viewpoint of the interplay between processes of different time scales is likely to shed light on bimodal phenomena in other complex systems, such as interevent times in earthquakes, rainfall, forest fire, and economic systems, etc.

  17. SPACE-R Thermionic Space Nuclear Power System: Design and Technology Demonstration Program (United States)


    This semiannual technical progress report summarizes the technical progress and accomplishments for the Thermionic Space Nuclear Power System (TI-SNPS) Design and Technology Demonstration Program of the prime contractor, Space Power Incorporated (SPI), its subcontractors, and supporting national laboratories during the first half of the government fiscal year (GFY) 1993. SPI's subcontractors and supporting national laboratories include: Babcock & Wilcox for the reactor core and externals; Space Systems/Loral for the spacecraft integration; Thermocore for the radiator heat pipes and the heat exchanger; INERTEK of CIS for the TFE, core elements, and nuclear tests; Argonne National Laboratories for nuclear safety, physics, and control verification; and Oak Ridge National laboratories for materials testing. Parametric trade studies are near completion. However, technical input from INERTEK has yet to be provided to determine some of the baseline design configurations. The INERTEK subcontract is expected to be initiated soon. The point design task has been initiated. The thermionic fuel element (TFE) is undergoing several design iterations. The reactor core vessel analysis and design has also been started.

  18. Primary zinc-air batteries for space power (United States)

    Bragg, Bobby J.; Bourland, Deborah S.; Merry, Glenn; Putt, Ron


    Prismatic HR and LC cells and batteries were built and tested, and they performed well with respect to the program goals of high capacity and high rate capability at specific energies. The HR batteries suffered reduced utilizations owing to dryout at the 2 and 3 A rates for the 50 C tests owing to the requirement for forced convection. The LC batteries suffered reduced utilizations under all conditions owing to the chimney effect at 1 G, although this effect would not occur at 0 G. An empirical model was developed which accurately predicted utilizations and average voltages for single cells, although thermal effects encountered during battery testing caused significant deviations, both positive and negative, from the model. Based on the encouraging results of the test program, we believe that the zinc-air primary battery of a flat, stackable configuration can serve as a high performance and safe power source for a range of space applications.

  19. Space and Terrestrial Power System Integration Optimization Code BRMAPS for Gas Turbine Space Power Plants With Nuclear Reactor Heat Sources (United States)

    Juhasz, Albert J.


    In view of the difficult times the US and global economies are experiencing today, funds for the development of advanced fission reactors nuclear power systems for space propulsion and planetary surface applications are currently not available. However, according to the Energy Policy Act of 2005 the U.S. needs to invest in developing fission reactor technology for ground based terrestrial power plants. Such plants would make a significant contribution toward drastic reduction of worldwide greenhouse gas emissions and associated global warming. To accomplish this goal the Next Generation Nuclear Plant Project (NGNP) has been established by DOE under the Generation IV Nuclear Systems Initiative. Idaho National Laboratory (INL) was designated as the lead in the development of VHTR (Very High Temperature Reactor) and HTGR (High Temperature Gas Reactor) technology to be integrated with MMW (multi-megawatt) helium gas turbine driven electric power AC generators. However, the advantages of transmitting power in high voltage DC form over large distances are also explored in the seminar lecture series. As an attractive alternate heat source the Liquid Fluoride Reactor (LFR), pioneered at ORNL (Oak Ridge National Laboratory) in the mid 1960's, would offer much higher energy yields than current nuclear plants by using an inherently safe energy conversion scheme based on the Thorium --> U233 fuel cycle and a fission process with a negative temperature coefficient of reactivity. The power plants are to be sized to meet electric power demand during peak periods and also for providing thermal energy for hydrogen (H2) production during "off peak" periods. This approach will both supply electric power by using environmentally clean nuclear heat which does not generate green house gases, and also provide a clean fuel H2 for the future, when, due to increased global demand and the decline in discovering new deposits, our supply of liquid fossil fuels will have been used up. This is

  20. Evaluation and comparison of space solar power concepts (United States)

    Feingold, Harvey; Carrington, Connie


    The SSP Exploratory Research and Technology (SERT) program undertaken by NASA in the 1999-2000 timeframe was the third in a recent series of NASA sponsored studies of Space Solar Power (SSP) that began with the 1995 SSP "Fresh Look" Study, and was followed by the SSP Concept Definition Study in 1998. In all three studies, a major focus has been on identifying system concepts, architectures and technologies that may ultimately produce a practical, economically viable source of electrical power to help satisfy the world's growing energy needs. As part of the SERT program, members of the study team developed several new and innovative SSP concepts that sprung from a desire to address the problem areas of previous system concepts with new technology and system solutions. In the previous SSP studies it has been shown that systems analyses and sensitivity studies are key to understanding the merits of different system concepts and technologies, particularly with respect to their impact on the mass and cost of space hardware and their ultimate economic impact on the cost of SSP-produced electricity. Enabled by analytical models and tools developed over the series of SSP studies, seven different system concepts as well as different technology choices within these concepts were quantitatively compared with one another on the basis of the mass and cost metrics suggested above. Accompanying sensitivity studies have permitted examination of how variations in the projected capabilities of different technologies could affect conclusions drawn from these analyses. This paper summarizes the results of these analytical efforts and from those results, identifies the most promising SSP concepts, including their key technologies and their comparative advantages and disadvantages.

  1. Power Electronics Being Developed for Deep Space Cryogenic Applications (United States)

    Patterson, Richard L.; Hammoud, Ahmad


    Electronic circuits and systems designed for deep space missions need to operate reliably and efficiently in harsh environments that include very low temperatures. Spacecraft that operate in such cold environments carry a large number of heaters so that the ambient temperature for the onboard electronics remains near 20 C. Electronics that can operate at cryogenic temperatures will simplify system design and reduce system size and weight by eliminating the heaters and their associated structures. As a result, system development and launch cost will be reduced. At the NASA Glenn Research Center, an ongoing program is focusing on the development of power electronics geared for deep space low-temperature environments. The research and development efforts include electrical components design, circuit design and construction, and system integration and demonstration at cryogenic temperatures. Investigations are being carried out on circuits and systems that are targeted for use in NASA missions where low temperatures will be encountered: devices such as ceramic and tantalum capacitors, metal film resistors, semiconductor switches, magnetics, and integrated circuits including dc/dc converters, operational amplifiers, voltage references, and motor controllers. Test activities cover a wide range of device and circuit performance under simple as well as complex test conditions, such as multistress and thermal cycling. The effect of low-temperature conditions on the switching characteristics of an advanced silicon-on-insulator field effect transistor is shown. For gate voltages (VGS) below 2.6 V, drain currents at -190 C are lower than drain currents at room temperature (20 C).

  2. Advanced Fusion Reactors for Space Propulsion and Power Systems (United States)

    Chapman, John J.


    In recent years the methodology proposed for conversion of light elements into energy via fusion has made steady progress. Scientific studies and engineering efforts in advanced fusion systems designs have introduced some new concepts with unique aspects including consideration of Aneutronic fuels. The plant parameters for harnessing aneutronic fusion appear more exigent than those required for the conventional fusion fuel cycle. However aneutronic fusion propulsion plants for Space deployment will ultimately offer the possibility of enhanced performance from nuclear gain as compared to existing ionic engines as well as providing a clean solution to Planetary Protection considerations and requirements. Proton triggered 11Boron fuel (p- 11B) will produce abundant ion kinetic energy for In-Space vectored thrust. Thus energetic alpha particles "exhaust" momentum can be used directly to produce high ISP thrust and also offer possibility of power conversion into electricity. p- 11B is an advanced fusion plant fuel with well understood reaction kinematics but will require some new conceptual thinking as to the most effective implementation.

  3. Dispersion modeling of thermal power plant emissions on stochastic space (United States)

    Gorle, J. M. R.; Sambana, N. R.


    This study aims to couple a deterministic atmospheric dispersion solver based on Gaussian model with a nonintrusive stochastic model to quantify the propagation of multiple uncertainties. The nonintrusive model is based on probabilistic collocation framework. The advantage of nonintrusive nature is to retain the existing deterministic plume dispersion model without missing the accuracy in extracting the statistics of stochastic solution. The developed model is applied to analyze the SO2 emission released from coal firing unit in the second stage of the National Thermal Power Corporation (NTPC) in Dadri, India using "urban" conditions. The entire application is split into two cases, depending on the source of uncertainty. In case 1, the uncertainties in stack gas exit conditions are used to construct the stochastic space while in case 2, meteorological conditions are considered as the sources of uncertainty. Both cases develop 2D uncertain random space in which the uncertainty propagation is quantified in terms of plume rise and pollutant concentration distribution under slightly unstable atmospheric stability conditions. Starting with deterministic Gaussian plume model demonstration and its application, development of stochastic collocation model, convergence study, error analysis, and uncertainty quantification are presented in this paper.

  4. Integrated Power and Attitude Control Systems for Space Station (United States)

    Oglevie, R. E.; Eisenhaure, D. B.


    Integrated Power and Attitude Control Systems (IPACS) studies performed over a decade ago established the feasibility of simultaneously storing electrical energy in wheels and utilizing the resulting momentum for spacecraft attitude control. It was shown that such a system possessed many advantages over other contemporary energy storage and attitude control systems in many applications. More recent technology advances in composite rotors, magnetic bearings, and power control electronics have triggered new optimism regarding the feasibility and merits of such a system. The paper presents the results of a recent study whose focus was to define an advanced IPACS and to evaluate its merits for the Space Station application. A system and component design concept is developed to establish the system performance capability. A system level trade study, including life-cycle costing, is performed to define the merits of the system relative to two other candidate systems. It is concluded that an advanced IPACS concept is not only feasible, but offers substantial savings in mass, and life-cycle cost.

  5. International Space Station power module thermal control system hydraulic performance

    Energy Technology Data Exchange (ETDEWEB)

    Goldberg, V. [Boeing North American, Inc., Canoga Park, CA (United States). Rocketdyne Div.


    The International Space Station (ISS) uses four photovoltaic power modules (PVMs) to provide electric power for the US On-Orbit Segment. The PVMs consist of photovoltaic arrays (PVAs), orbit replaceable units (ORUs), photovoltaic radiators (PVRs), and a thermal control system (TCS). The PVM TCS function is to maintain selected PVM components within their specified operating ranges. The TCS consists of the pump flow control subassembly (PFCS), piping system, including serpentine tubing for individual component heat exchangers, headers/manifolds, fluid disconnect couplings (FQDCs), and radiator (PVR). This paper describes the major design requirements for the TCS and the results of the system hydraulic performance predictions in regard to these requirements and system component sizing. The system performance assessments were conducted using the PVM TCS fluid network hydraulic model developed for predicting system/component pressure losses and flow distribution. Hardy-Cross method of iteration was used to model the fluid network configuration. Assessments of the system hydraulic performance were conducted based on an evaluation of uncertainties associated with the manufacturing and design tolerances. Based on results of the analysis, it was concluded that all design requirements regarding system performance could be met. The hydraulic performance range, enveloping possible system operating parameter variations was determined.

  6. Past, present, and future activities in space power technology in the United States of America (United States)

    Ambrus, Judith H.


    Space power technology research in the U.S. is examined. The objectives for advanced power systems are long life, safety, flexibility, modularity, growth capability, and autonomy. Research in the areas of photovoltaic arrays, electrical energy storage, and the development of solar dynamic power systems and radio thermal generators is described. The applications of advances in power generation, energy storage, and power management and distribution to the Space Station are discussed.

  7. Catalogue of space objects and events as a powerful tool for scientific researches on space debris (United States)

    Agapov, V.; Stepanyants, V.; Tuchin, A.; Khutorovsky, Z.

    Wide work on developing and maintenance of the Catalogue of scientific information on space objects and events is continuing at the Keldysh Institute of Applied Mathematics. The work is making in cooperation with Russian company "Space information analytical systems" (KIA Systems). Powerful software tool is developed by now including:- informational core (relational database in RDBMS Oracle 8i environment)with special tools for automatic initial processing and systematization ofdata- software complex for orbital modeling and space objects and eventsdynamical catalogue maintenance- special information - analytical software Informational core covers wide spectrum of data needed for following purposes:- full-scale and high quality modeling of object's motion in near-Earth space(orbital and measurement data, solar flux and geomagnetic indices, Earthrotation parameters etc.)- determination of various events parameters (launches, manoeuvres,fragmentations etc.)- analysis of space debris sources- studying long-term orbital evolution (over several years or tens of years)- other The database is storing huge volume of data including:- optical measurements- TLEs- information about all space launches took place since 1957- information about space missions and programs- manoeuvres- fragmentations- launch sequences for typical orbital insertions- various characteristics for orbital objects (payloads, stages, fragments)- officially released UN and ITU registration data- other By now there are records storing in informational core for more than 28000 orbital objects (both catalogued and not), about all orbital launch attempts since 04.10.1957 (including failed ones), more than 30millions records of orbital information (TLEs, state vectors, polynomial data), more than 200000 optical measurements (normal places) for GEO region objects, calculated data on more than 14 millions of close approaches had taken place during last five years and other data. Software complex for orbital

  8. Radioisotope fueled pulsed power generation system for propulsion and electrical power for deep space missions (United States)

    Howe, Troy

    Space exploration missions to the moon, Mars, and other celestial bodies have allowed for great scientific leaps to enhance our knowledge of the universe; yet the astronomical cost of these missions limits their utility to only a few select agencies. Reducing the cost of exploratory space travel will give rise to a new era of exploration, where private investors, universities, and world governments can send satellites to far off planets and gather important data. By using radioisotope power sources and thermal storage devices, a duty cycle can be introduced to extract large amounts of energy in short amounts of time, allowing for efficient space travel. The same device can also provide electrical power for subsystems such as communications, drills, lasers, or other components that can provide valuable scientific information. This project examines the use of multiple radioisotope sources combined with a thermal capacitor using Phase Change Materials (PCMs) which can collect energy over a period of time. The result of this design culminates in a variety of possible spacecraft with their own varying costs, transit times, and objectives. Among the most promising are missions to Mars which cost less than 17M, missions that can provide power to satellite constellations for decades, or missions that can deliver large, Opportunity-sized (185kg) payloads to mars for less than 53M. All made available to a much wider range of customer with commercially available satellite launches from earth. The true cost of such progress though lies in the sometimes substantial increase in transit times for these missions.

  9. 78 FR 1848 - Plutonium-238 Production for Radioisotope Power Systems for National Aeronautics and Space... (United States)


    ... Plutonium-238 Production for Radioisotope Power Systems for National Aeronautics and Space Administration...-238 (Pu-238) for radioisotope power systems (RPSs) to support the National Aeronautics and Space... Radioisotope Power Systems (Draft Consolidation EIS) in 2005 to consolidate the nuclear operations related...

  10. 46 CFR 111.103-1 - Power ventilation systems except machinery space ventilation systems. (United States)


    ... 46 Shipping 4 2010-10-01 2010-10-01 false Power ventilation systems except machinery space ventilation systems. 111.103-1 Section 111.103-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... Power ventilation systems except machinery space ventilation systems. Each power ventilation system...

  11. Tolerance and nature of residual refraction in symmetric power space as principal lens powers and meridians change. (United States)

    Abelman, Herven; Abelman, Shirley


    Unacceptable principal powers in well-centred lenses may require a toric over-refraction which differs in nature from the one where correct powers have misplaced meridians. This paper calculates residual (over) refractions and their natures. The magnitude of the power of the over-refraction serves as a general, reliable, real scalar criterion for acceptance or tolerance of lenses whose surface relative curvatures change or whose meridians are rotated and cause powers to differ. Principal powers and meridians of lenses are analogous to eigenvalues and eigenvectors of symmetric matrices, which facilitates the calculation of powers and their residuals. Geometric paths in symmetric power space link intended refractive correction and these carefully chosen, undue refractive corrections. Principal meridians alone vary along an arc of a circle centred at the origin and corresponding powers vary autonomously along select diameters of that circle in symmetric power space. Depending on the path of the power change, residual lenses different from their prescription in principal powers and meridians are pure cross-cylindrical or spherocylindrical in nature. The location of residual power in symmetric dioptric power space and its optical cross-representation characterize the lens that must be added to the compensation to attain the power in the prescription.

  12. Tolerance and Nature of Residual Refraction in Symmetric Power Space as Principal Lens Powers and Meridians Change

    Directory of Open Access Journals (Sweden)

    Herven Abelman


    Full Text Available Unacceptable principal powers in well-centred lenses may require a toric over-refraction which differs in nature from the one where correct powers have misplaced meridians. This paper calculates residual (over refractions and their natures. The magnitude of the power of the over-refraction serves as a general, reliable, real scalar criterion for acceptance or tolerance of lenses whose surface relative curvatures change or whose meridians are rotated and cause powers to differ. Principal powers and meridians of lenses are analogous to eigenvalues and eigenvectors of symmetric matrices, which facilitates the calculation of powers and their residuals. Geometric paths in symmetric power space link intended refractive correction and these carefully chosen, undue refractive corrections. Principal meridians alone vary along an arc of a circle centred at the origin and corresponding powers vary autonomously along select diameters of that circle in symmetric power space. Depending on the path of the power change, residual lenses different from their prescription in principal powers and meridians are pure cross-cylindrical or spherocylindrical in nature. The location of residual power in symmetric dioptric power space and its optical cross-representation characterize the lens that must be added to the compensation to attain the power in the prescription.

  13. An Ultra Low Power Cryo-Refrigerator for Space Project (United States)

    National Aeronautics and Space Administration — Future NASA Space Science Missions will incorporate detectors, sensors, shields, and telescopes that must be cooled to cryogenic temperatures. An enabling technology...

  14. An Ultra Low Power Cryo-Refrigerator for Space Project (United States)

    National Aeronautics and Space Administration — Future NASA Space Science Missions will incorporate detectors, sensors, shields, and telescopes that must be cooled to cryogenic temperatures. An enabling...

  15. Observing power blackouts from space - A disaster related study (United States)

    Aubrecht, C.; Elvidge, C. D.; Ziskin, D.; Baugh, K. E.; Tuttle, B.; Erwin, E.; Kerle, N.


    capability of detecting power blackouts in OLS data have been identified (e.g. sunlight, heavy cloud cover and bright moonlight). Furthermore, the change detection procedure only works when power blackouts happen or still persist at night at the time of an OLS overpass. In some cases (e.g. Hurricane Katrina) it has been possible to track the gradual recovery of power by repeating the procedure on nights following a disaster event. In this paper several examples of successful power blackout detection following natural disasters including hurricanes (e.g. Isabel 2003 and Wilma 2005 in the USA) and earthquakes (e.g. Gujarat Earthquake 2001 in India) will be presented, whereas overlaid hurricane paths and earthquake epicenters serve as landmarks and indicate locations around the potential highest impact. Disaster impact assessment and post-disaster research is strongly related to impacts on population, related infrastructure and activities (Kerle et al. 2005, Zhang and Kerle 2008). In particular in the case of emergency management and response humans are the main actors and first-pass assessment of affected population and locations of affected areas are essential. Space-based power blackout detection, as described above, has the potential to delineate the spatial extent of the disaster impact. Overlaying the respective OLS data with regional population data such as LandScan (Dobson et al. 2000) or Gridded Population of the World (CIESIN and CIAT 2005) allows estimating a potential number of affected people. Without a doubt such estimates comprise a considerable number of uncertainties. However, the capability of providing the information in near-real time as offered by using DMSP-OLS makes the presented approach very valuable for emergency and disaster managers worldwide. REFERENCES Center for International Earth Science Information Network CIESIN at Columbia University, and Centro Internacional de Agricultura Tropical CIAT (2005). Gridded Population of the World Version 3 (GPWv

  16. High Power Electro-Optic Modulator for Space-Based Applications Project (United States)

    National Aeronautics and Space Administration — ADVR, Inc. proposes the development of a fiber coupled, high power, electro-optically controlled, space qualified, phase modulator for the NASA Laser Interferometer...

  17. High Power Electro-Optic Modulator for Space-Based Applications Project (United States)

    National Aeronautics and Space Administration — This Small Business Innovation Research Phase I effort will establish the feasibility of developing a fiber coupled, high power, electro-optically controlled, space...

  18. Hypermodular Self-Assembling Space Solar Power -- Design Option for Mid-Term GEO Utility-Scale Power Plants

    CERN Document Server

    Leitgab, Martin


    This paper presents a design for scaleable space solar power systems based on free-flying reflectors and module self-assembly. Lower system cost of utility-scale space solar power is achieved by design independence of yet-to-be-built in-space assembly or transportation infrastructure. Using current and expected near-term technology, this study describe a design for mid-term utility-scale power plants in geosynchronous orbits. High-level economic considerations in the context of current and expected future launch costs are given as well.

  19. Language choice in bimodal bilingual development

    Directory of Open Access Journals (Sweden)

    Diane eLillo-Martin


    Full Text Available Bilingual children develop sensitivity to the language used by their interlocutors at an early age, reflected in differential use of each language by the child depending on their interlocutor. Factors such as discourse context and relative language dominance in the community may mediate the degree of language differentiation in preschool age children.Bimodal bilingual children, acquiring both a sign language and a spoken language, have an even more complex situation. Their Deaf parents vary considerably in access to the spoken language. Furthermore, in addition to code-mixing and code-switching, they use code-blending – expressions in both speech and sign simultaneously – an option uniquely available to bimodal bilinguals. Code-blending is analogous to code-switching sociolinguistically, but is also a way to communicate without suppressing one language. For adult bimodal bilinguals, complete suppression of the non-selected language is cognitively demanding. We expect that bimodal bilingual children also find suppression difficult, and use blending rather than suppression in some contexts. We also expect relative community language dominance to be a factor in children’s language choices.This study analyzes longitudinal spontaneous production data from four bimodal bilingual children and their Deaf and hearing interlocutors. Even at the earliest observations, the children produced more signed utterances with Deaf interlocutors and more speech with hearing interlocutors. However, while three of the four children produced >75% speech alone in speech target sessions, they produced <25% sign alone in sign target sessions. All four produced bimodal utterances in both, but more frequently in the sign sessions, potentially because they find suppression of the dominant language more difficult.Our results indicate that these children are sensitive to the language used by their interlocutors, while showing considerable influence from the dominant

  20. A New Probabilistic Transformation in Generalized Power Space

    Institute of Scientific and Technical Information of China (English)

    HU Lifang; HE You; GUAN Xin; DENG Yong; HAN Deqiang


    The mapping from the belief to the probability domain is a controversial issue,whose original purpose is to make(hard) decision,but for contrariwise to erroneous widespread idea/claim,this is not the only interest for using such mappings nowadays.Actually the probabilistic transformations of belief mass assignments are very useful in modern multitarget multisensor tracking systems where one deals with soft decisions,especially when precise belief structures are not always available due to the existence of uncertainty in human being's subjective judgments.Therefore,a new probabilistic transformation of interval-valued belief structure is put forward in the generalized power space,in order to build a subjective probability measure from any basic belief assignment defined on any model of the frame of discernment.Several examples are given to show how the new transformation works and we compare it to the main existing transformations proposed in the literature so far.Results are provided to illustrate the rationality and efficiency of this new proposed method making the decision problem simpler.

  1. Mapping a New Geography of Space and Power

    Directory of Open Access Journals (Sweden)

    Nicole Fabricant


    Full Text Available In this paper, I analyze the ways in which MST-Bolivia (Movimiento Sin Tierra forged a national-level movement through one counter-hegemonic event: the Fifth Indigenous March for Land and Territory, which originated in Santa Cruz de la Sierra in October 2006.  This march enacted a powerful performance of pan-indigenous solidarity and nationalistic sentiment which led to a public declaration by president Evo Morales to approve the New Agrarian Reform Law. I focus in particular on the organizational and spatial structure of the march, and on the significance of seizing public space in protest.  En este trabajo analizo cómo el MST-Bolivia (Movimiento Sin Tierra forjó un movimiento de alcance nacional a través de un evento contra-hegemónico: la Quinta Marcha Indígena por la Tierra y el Territorio, originada en Santa Cruz de la Sierra en octubre de 2006. Esta Marcha articuló un poderoso performance de solidaridad y nacionalismo pan-indígena que llevó al Presidente Evo Morales a declarar públicamente la aprobación de la Ley de Reconversión Comunitaria de la Reforma Agraria. En mi trabajo me enfoco particularmente en la estructura organizativa y espacial de la Marcha como también en los efectos que produce la toma del espacio público en signo de protesta.

  2. Gas Foil Bearings for Space Propulsion Nuclear Electric Power Generation (United States)

    Howard, Samuel A.; DellaCorte, Christopher


    The choice of power conversion technology is critical in directing the design of a space vehicle for the future NASA mission to Mars. One candidate design consists of a foil bearing supported turbo alternator driven by a helium-xenon gas mixture heated by a nuclear reactor. The system is a closed-loop, meaning there is a constant volume of process fluid that is sealed from the environment. Therefore, foil bearings are proposed due to their ability to use the process gas as a lubricant. As such, the rotor dynamics of a foil bearing supported rotor is an important factor in the eventual design. The current work describes a rotor dynamic analysis to assess the viability of such a system. A brief technology background, assumptions, analyses, and conclusions are discussed in this report. The results indicate that a foil bearing supported turbo alternator is possible, although more work will be needed to gain knowledge about foil bearing behavior in helium-xenon gas.

  3. Periodicity in bimodal atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Lai, Chia-Yun; Santos, Sergio, E-mail:; Chiesa, Matteo [Laboratory for Energy and NanoScience (LENS), Institute Center for Future Energy (iFES), Masdar Institute of Science and Technology, Abu Dhabi (United Arab Emirates); Barcons, Victor [Departament de Disseny i Programació de Sistemes Electrònics, UPC - Universitat Politècnica de Catalunya, Av. Bases, 61, 08242 Manresa (Barcelona) (Spain)


    Periodicity is fundamental for quantification and the application of conservation principles of many important systems. Here, we discuss periodicity in the context of bimodal atomic force microscopy (AFM). The relationship between the excited frequencies is shown to affect and control both experimental observables and the main expressions quantified via these observables, i.e., virial and energy transfer expressions, which form the basis of the bimodal AFM theory. The presence of a fundamental frequency further simplifies the theory and leads to close form solutions. Predictions are verified via numerical integration of the equation of motion and experimentally on a mica surface.

  4. High-Temperature, Wirebondless, Ultra-Compact Wide Bandgap Power Semiconductor Modules for Space Power Systems Project (United States)

    National Aeronautics and Space Administration — Silicon carbide (SiC) and other wide band-gap semiconductors offer great promise of high power rating, high operating temperature, simple thermal management, and...

  5. Low-Power Formaldehyde Detector for Space Applications Project (United States)

    National Aeronautics and Space Administration — Trace contamination of the International Space Station (ISS) by formaldehyde -- a known carcinogen -- is a significant threat to crew health. The spacecraft maximum...

  6. Low-power formaldehyde detector for space applications Project (United States)

    National Aeronautics and Space Administration — Trace contamination of the International Space Station (ISS) by formaldehyde?a known carcinogen? is a significant potential threat to crew health. The spacecraft...

  7. Enabling lunar and space missions by laser power transmission (United States)

    De Young, R. J.; Nealy, J. E.; Humes, D. H.; Meador, W. E.


    Applications are proposed for laser power transmission on the Moon. A solar-pumped laser in lunar orbit would beam power to the lunar surface for conversion into either electricity or propulsion needs. For example, lunar rovers could be much more flexible and lighter than rovers using other primary power sources. Also, laser power could be absorbed by lunar soil to create a hard glassy surface for dust-free roadways and launch pads. Laser power could also be used to power small lunar rockets or orbital transfer vehicles, and finally, photovoltaic laser converters could power remote excavation vehicles and human habitats. Laser power transmission is shown to be a highly flexible, enabling primary power source for lunar missions.

  8. Enabling lunar and space missions by laser power transmission (United States)

    Deyoung, R. J.; Nealy, J. E.; Humes, D. H.; Meador, W. E.


    Applications are proposed for laser power transmission on the Moon. A solar-pumped laser in lunar orbit would beam power to the lunar surface for conversion into either electricity or propulsion needs. For example, lunar rovers could be much more flexible and lighter than rovers using other primary power sources. Also, laser power could be absorbed by lunar soil to create a hard glassy surface for dust-free roadways and launch pads. Laser power could also be used to power small lunar rockets or orbital transfer vehicles, and finally, photovoltaic laser converters could power remote excavation vehicles and human habitats. Laser power transmission is shown to be a highly flexible, enabling primary power source for lunar missions.

  9. Deaf Children's Bimodal Bilingualism and Education (United States)

    Swanwick, Ruth


    This paper provides an overview of the research into deaf children's bilingualism and bilingual education through a synthesis of studies published over the last 15 years. This review brings together the linguistic and pedagogical work on bimodal bilingualism to inform educational practice. The first section of the review provides a synthesis of…

  10. Bimodal Networks as Candidates for Electroactive Polymers

    DEFF Research Database (Denmark)

    Bahrt, Frederikke; Daugaard, Anders Egede; Bejenariu, Anca Gabriela;

    An alternative network formulation method was adopted in order to obtain a different type of silicone based elastomeric systems - the so-called bimodal networks - using two vinyl-terminated polydimethyl siloxanes (PDMS) of different molecular weight, a labelled crosslinker (3 or 4-functional), an...

  11. Toward an Air and Space Force: Naval Aviation and the Implications for Space Power (United States)


    hour support center that manages all requests relating to USAF space systems. 85. Ibid. 86. Cliff D. Ozmun , “Air Force Space Command Establishes First...Shield Declares Victory.” Space Tactics Bulletin 2, Issue 1 (November 1994): 3–4. Ozmun , Cliff D. “Air Force Space Command Establishes First Space

  12. Power, Space and Resistance: Foucauldian Reading of "The Pickup" (United States)

    Babapi, Nasrin; Parvaneh, Farid


    The present article is an attempt to read Nadin Gordimer's "The Pickup" from the lens of Foucault. It starts with Foucault's assumption that power is everything and any kind of relation in the world is defined through the discourses of power. It discusses the techniques through which the power dominates its authority over the subjects…

  13. Development of a Robust Tri-Carbide Fueled Reactor for Multimegawatt Space Power and Propulsion Applications

    Energy Technology Data Exchange (ETDEWEB)

    Samim Anghaie; Travis W. Knight; Johann Plancher; Reza Gouw


    An innovative reactor core design based on advanced, mixed carbide fuels was analyzed for nuclear space power applications. Solid solution, mixed carbide fuels such as (U,Zr,Nb)c and (U,Zr, Ta)C offer great promise as an advanced high temperature fuel for space power reactors.

  14. Lightweight Radiator Fins for Space Nuclear Power Project (United States)

    National Aeronautics and Space Administration — This SBIR Phase 1 project shall investigate concept radiator fins that incorporate novel carbon materials for improved performance of segmented high temperature...

  15. Thermo-Acoustic Convertor for Space Power Project (United States)

    National Aeronautics and Space Administration — Sunpower will introduce thermoacoustic Stirling heat engine (TASHE) technology into its existing Stirling convertor technology to eliminate the moving mechanical...

  16. Toward space solar power: Wireless energy transmission experiments past, present and future (United States)

    Little, Frank E.; McSpadden, James O.; Chang, Kai; Kaya, Nobuyuki


    Solar power is a reality. Today, increasing numbers of photovoltaic and other solar-powered installations are in service around the world and in space. These uses range from the primary electric power source for satellites, remote site scientific experiments and villages in developing countries to augmenting the commercial electric grid and providing partial power for individual businesses and homeowners in developed countries. In space, electricity generated by photovoltaic conversion of solar energy is the mainstay of power for low Earth and geostationary satellite constellations. Still, for all its acceptance as a benign and environmentally friendly energy source, terrestrial solar power has yet to be seriously considered a viable technology for providing base electrical generating capacity. The obvious reason is sunshine on Earth is too unreliable. In addition to the diurnal and seasonal cycles, inclement weather reduces the average daily period and intensity of insolation. However, the Sun shines constantly in space. The challenge is to harvest and transmit the energy from space to Earth. The concept of space solar power based on microwave wireless energy transmission was first put forth more than 25 years ago by Dr. Peter Glaser. We review historical experiments in wireless energy transmission which have brought the technology from a laboratory curiosity to its present status. Results from recent experiments and their implications for wireless energy transmission as an enabling technology for space solar power are reviewed. Current developments are discussed along with proposed terrestrial and space experiments.

  17. Wireless Power Transfer by Means of Electromagnetic Radiation Within an Enclosed Space

    CERN Document Server

    Moffatt, Robert A


    In this paper, wireless power transfer by means of electromagnetic radiation is investigated. Formulas are derived for the efficiency of the power transfer in free space, in the presence of reflecting surfaces, and within enclosed spaces. It is found that the presence of reflecting surfaces has the capacity to substantially enhance the efficiency of power transfer at long range. An upper limit is also found for the transferred power when constraints are imposed on certain forms of undesired absorption. For the sake of simplicity, only the efficiency of the radiative power transfer is considered. Losses due to resistance in the antenna structures or inefficiencies in RF to DC conversion are neglected.

  18. Space Power Free-Piston Stirling Engine Scaling Study (United States)

    Jones, D.


    The design feasibility study is documented of a single cylinder, free piston Stirling engine/linear alternator (FPSE/LA) power module generating 150 kW-electric (kW sub e), and the determination of the module's maximum feasible power level. The power module configuration was specified to be a single cylinder (single piston, single displacer) FPSE/LA, with tuning capacitors if required. The design requirements were as follows: (1) Maximum electrical power output; (2) Power module thermal efficiency equal to or greater than 20 percent at a specific mass of 5 to 8 kg/kW(sub e); (3) Heater wall temperature/cooler wall temperature = 1050 K/525 K; (4) Sodium heat-pipe heat transport system, pumped loop NaK (sodium-potassium eutectic mixture) rejection system; (5) Maximum power module vibration amplitude = 0.0038 cm; and (6) Design life = 7 years (60,000 hr). The results show that a single cylinder FPSE/LA is capable of meeting program goals and has attractive scaling attributes over the power range from 25 to 150 kW(sub e). Scaling beyond the 150 kW(sub e) power level, the power module efficiency falls and the power module specific mass reaches 10 kg/kW(sub e) at a power output of 500 kW(sub e). A discussion of scaling rules for the engine, alternator, and heat transport systems is presented, along with a detailed description of the conceptual design of a 150 kW(sub e) power module that meets the requirements. Included is a discussion of the design of a dynamic balance system. A parametric study of power module performance conducted over the power output range of 25 to 150 kW(sub e) for temperature ratios of 1.7, 2.0, 2.5, and 3.0 is presented and discussed. The results show that as the temperature ratio decreases, the efficiency falls and specific mass increases. At a temperature ratio of 1.7, the 150 kW(sub e) power module cannot satisfy both efficiency and specific mass goals. As the power level increases from 25 to 150 kW(sub e) at a fixed temperature ratio, power

  19. HRM, POWER and possible spaces of becoming human

    DEFF Research Database (Denmark)

    Bramming, Pia


    institutions, the power of aleader or person in terms of the right to execute punishment and the duty to obedienceor empowerment, as a countermove to the effects of bureaucratic workplace routines`... where initiative is stifled and workers become alienated'1. Indirectly one canidentify power as interesting...


    Institute of Scientific and Technical Information of China (English)

    Wu Gang; Chen Ming; Wang Haifeng; Cheng Shixin


    Space-time trellis codes can achieve the best tradeoff among bandwidth effciency,diversity gain, constellation size and trellis complexity. In this paper, some optimum low rate space-time trellis codes are proposed. Performance analysis and simulation show that the low rate space-time trellis codes outperform space-time block codes concatenated with convolutional code at the same bandwidth effciency, and are more suitable for the power limited wireless communication system.

  1. Striction-based Power Monitoring in Space Environment Project (United States)

    National Aeronautics and Space Administration — The program will leverage recent advances in striction materials and coupled striction devices as to enable highly isolated (analog) voltage and current flow sensors...

  2. A Low Input Power Cryocooler for Space Applications Project (United States)

    National Aeronautics and Space Administration — Future NASA missions will require cryocoolers providing cooling capacities upwards of 0.3W at 35K with heat rejection capability to temperature sinks as low as 150K...

  3. Thermo-Acoustic Convertor for Space Power Project (United States)

    National Aeronautics and Space Administration — In Phase Sunpower looked at Thermoacoustic Stirling Heat Engines (TASHEs). These ranged from a TASHE which was sized for the heat from a single General Purpose Heat...

  4. Advanced Space Power Systems (ASPS): Advanced Energy Storage Systems Project (United States)

    National Aeronautics and Space Administration — The development of high specific energy devices will enable NASA’s future robotic and human-exploration missions.  The need for advances in energy storage...

  5. Advanced Modular Power Approach to Affordable, Supportable Space Systems (United States)

    Oeftering, Richard C.; Kimnach, Greg L.; Fincannon, James; Mckissock,, Barbara I.; Loyselle, Patricia L.; Wong, Edmond


    Recent studies of missions to the Moon, Mars and Near Earth Asteroids (NEA) indicate that these missions often involve several distinct separately launched vehicles that must ultimately be integrated together in-flight and operate as one unit. Therefore, it is important to see these vehicles as elements of a larger segmented spacecraft rather than separate spacecraft flying in formation. The evolution of large multi-vehicle exploration architecture creates the need (and opportunity) to establish a global power architecture that is common across all vehicles. The Advanced Exploration Systems (AES) Modular Power System (AMPS) project managed by NASA Glenn Research Center (GRC) is aimed at establishing the modular power system architecture that will enable power systems to be built from a common set of modular building blocks. The project is developing, demonstrating and evaluating key modular power technologies that are expected to minimize non-recurring development costs, reduce recurring integration costs, as well as, mission operational and support costs. Further, modular power is expected to enhance mission flexibility, vehicle reliability, scalability and overall mission supportability. The AMPS project not only supports multi-vehicle architectures but should enable multi-mission capability as well. The AMPS technology development involves near term demonstrations involving developmental prototype vehicles and field demonstrations. These operational demonstrations not only serve as a means of evaluating modular technology but also provide feedback to developers that assure that they progress toward truly flexible and operationally supportable modular power architecture.

  6. Recent developments in refractive concentrators for space photovoltaic power systems (United States)

    Piszczor, Michael F.; Oneill, Mark J.


    Since SPRAT 11, significant progress has been made in the development of refractive concentrator elements and components designed specifically for space applications. The status of the mini-dome Fresnel lens concentrator array is discussed and then the results of work recently completed in the area of prismatic cell covers for concentrator systems are summarized. This is followed by a brief discussion of some work just starting in the area of line-focus refractive concentrators for space.

  7. Democritos: preparing demonstrators for high power nuclear electric space propulsion


    Masson, Frederic; Ruault, Jean-Marc; WORMS, Jean-Claude; Detsis, Emmanouil; Beaurain, André; Lassoudiere, Francois; Gaia, Enrico; Tosi, Maria -Christina; Jansen, Frank; Bauer, Waldemar; Semenkin, Alexander; Tinsley, Tim; Hodgson, Zara


    The Democritos project aims at preparing demonstrators for a megawatt class nuclearelectric space propulsion. It is funded by Horizon 2020, the R&T program of the European Community. It is a new European and Russian project, including as partners: Nuclear National Laboratory (U.K.), DLR (Germany), The Keldysh Research Center (Russia), Thales Alenia Space Italia (Italy), Snecma (France), ESF (France) and CNES (France). IEAV (Brazil) will join as an observer. Democritos is the follo...

  8. Synthesis and Characterization of Bimodal Mesoporous Silica

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiaofang; GUO Cuili; WANG Xiaoli; WU Yuanyuan


    Mesoporous silica with controllable bimodal pore size distribution was synthesized with cetyltrimethylammonium bromide (CTAB) as chemical template for small mesopores and silica gel as physical template for large mesopores.The structure of synthesized samples were characterized by Fourier transform infrared (FT-IR) spectroscopy,X-ray diffraction (XRD),scanning electron microscopy (SEM),transmission electron microscopy (TEM) and N2 adsorption-desorption measurements.The experimental results show that bimodal mesoporous silica consists of small mesopores of about 3 nm and large mesopores of about 45 nm.The small mesopores which were formed on the external surface and pore walls of the silica gel had similar characters with those of MCM-41,while large mesopores were inherited from parent silica gel material.The pore size distribution of the synthesized silica can be adjusted by changing the relative content of TEOS and silica gel or the feeding sequence of silica gel and NH4OH.

  9. Building Power Between Polarities: On the Space-in-Between. (United States)

    Ventres, William B


    In this article, I introduce the concept of the space-in-between. This space-in-between is born of the realization that, between the expression of any two polarities (across dimensions such as emotion, thought, geography, and ideology), there exists a philosophical construct useful for framing thinking about practice, research, and managerial relationships in the health professions. Out of this construct emerge practical considerations useful for structuring the conduct of meaningful interpersonal and intercultural interactions. I describe how the idea of a space-in-between developed out of my medical practice, grew as a result of my experiences in international environments. and has found fulfillment in my ongoing work. I explore the application of a space-in-between in public health, medical anthropology, medical ethics, and global health. I review how, as a result of incorporating this space in their daily work, clinicians, educators, researchers, and managers can grow as leaders by sharing the presence that arises from the space-in-between them and the people in the communities they serve.

  10. Test facility of thermal storage equipment for space power generation (United States)

    Inoue, T.; Nakagawa, M.; Mochida, Y.; Ohtomo, F.; Shimizu, K.; Tanaka, K.; Abe, Y.; Nomura, O.; Kamimoto, M.

    A thermal storage equipment test facility has been built in connection with developing solar dynamic power systems (SDPSs). The test facility consists of a recuperative closed Brayton cycle system (CBC), with a mixture of helium and xenon with a molecular weight of 39.9 serving as the working fluid. CBC has been shown to be the most attractive power generation system among several types of SDPSs because of its ability to meet the required high power demand and its thermal efficiency, about 30 percent. The authors present a description of this test facility and give results of the preliminary test and the first-stage test with heat storage equipment.

  11. Community Coordinated Modeling Center: A Powerful Resource in Space Science and Space Weather Education (United States)

    Chulaki, A.; Kuznetsova, M. M.; Rastaetter, L.; MacNeice, P. J.; Shim, J. S.; Pulkkinen, A. A.; Taktakishvili, A.; Mays, M. L.; Mendoza, A. M. M.; Zheng, Y.; Mullinix, R.; Collado-Vega, Y. M.; Maddox, M. M.; Pembroke, A. D.; Wiegand, C.


    Community Coordinated Modeling Center (CCMC) is a NASA affiliated interagency partnership with the primary goal of aiding the transition of modern space science models into space weather forecasting while supporting space science research. Additionally, over the past ten years it has established itself as a global space science education resource supporting undergraduate and graduate education and research, and spreading space weather awareness worldwide. A unique combination of assets, capabilities and close ties to the scientific and educational communities enable this small group to serve as a hub for raising generations of young space scientists and engineers. CCMC resources are publicly available online, providing unprecedented global access to the largest collection of modern space science models (developed by the international research community). CCMC has revolutionized the way simulations are utilized in classrooms settings, student projects, and scientific labs and serves hundreds of educators, students and researchers every year. Another major CCMC asset is an expert space weather prototyping team primarily serving NASA's interplanetary space weather needs. Capitalizing on its unrivaled capabilities and experiences, the team provides in-depth space weather training to students and professionals worldwide, and offers an amazing opportunity for undergraduates to engage in real-time space weather monitoring, analysis, forecasting and research. In-house development of state-of-the-art space weather tools and applications provides exciting opportunities to students majoring in computer science and computer engineering fields to intern with the software engineers at the CCMC while also learning about the space weather from the NASA scientists.

  12. Bimodal representation of the tropical intraseasonal oscillation

    Energy Technology Data Exchange (ETDEWEB)

    Kikuchi, Kazuyoshi [University of Hawaii, International Pacific Research Center, School of Ocean and Earth Science and Technology, Manoa Honolulu, HI (United States); Wang, Bin [University of Hawaii, Department of Meteorology and International Pacific Research Center, School of Ocean and Earth Science and Technology, Manoa Honolulu, HI (United States); Kajikawa, Yoshiyuki [Nagoya University, Hydrospheric Atmospheric Research Center, Nagoya (Japan)


    The tropical intraseasonal oscillation (ISO) shows distinct variability centers and propagation patterns between boreal winter and summer. To accurately represent the state of the ISO at any particular time of a year, a bimodal ISO index was developed. It consists of Madden-Julian Oscillation (MJO) mode with predominant eastward propagation along the equator and Boreal Summer ISO (BSISO) mode with prominent northward propagation and large variability in off-equatorial monsoon trough regions. The spatial-temporal patterns of the MJO and BSISO modes are identified with the extended empirical orthogonal function analysis of 31 years (1979-2009) OLR data for the December-February and June-August period, respectively. The dominant mode of the ISO at any given time can be judged by the proportions of the OLR anomalies projected onto the two modes. The bimodal ISO index provides objective and quantitative measures on the annual and interannual variations of the predominant ISO modes. It is shown that from December to April the MJO mode dominates while from June to October the BSISO mode dominates. May and November are transitional months when the predominant mode changes from one to the other. It is also shown that the fractional variance reconstructed based on the bimodal index is significantly higher than the counterpart reconstructed based on the Wheeler and Hendon's index. The bimodal ISO index provides a reliable real time monitoring skill, too. The method and results provide critical information in assessing models' performance to reproduce the ISO and developing further research on predictability of the ISO and are also useful for a variety of scientific and practical purposes. (orig.)

  13. The Efficiency of the Bimodal System Transportation

    Directory of Open Access Journals (Sweden)

    Nada Štrumberger


    Full Text Available The development of fast railway results in an increased applicationof Trailer Train bimodal system transportation. Thetraffic costs are multiply reduced, particularly the variablecosts. On the other hand the environmental pollution from exhaustgases is also reduced. Therefore, by the year 2010 cargotransport should be preponderant~v used which would be characterisedby fast electric trains producing less noise, at lowercosts and with clean environment.

  14. Space Nuclear Power Public and Stakeholder Risk Communication (United States)

    Dawson, Sandra M.; Sklar, Maria


    The 1986 Challenger accident coupled with the Chernobyl nuclear reactor accident increased public concern about the safety of spacecraft using nuclear technology. While three nuclear powered spacecraft had been launched before 1986 with little public interest, future nuclear powered missions would see significantly more public concern and require NASA to increase its efforts to communicate mission risks to the public. In 1987 a separate risk communication area within the Launch Approval Planning Group of the Jet Propulsion Laboratory was created to address public concern about the health, environmental, and safety risks of NASA missions. The lessons learned from the risk communication strategies developed for the nuclear powered Galileo, Ulysses, and Cassini missions are reviewed in this paper and recommendations are given as to how these lessons can be applied to future NASA missions that may use nuclear power systems and other potentially controversial NASA missions.

  15. Minimizing Losses in a Space Laser Power Beaming System (United States)


    Society for Optica Engineering 1994. Linden , D., & Reddy, T. B. Handbook of Batteries 3rd Edition. New York: McGraw- Hill, 2002. Luque. Solar Cells and... Linden & Reddy, 2002: Chapter 1). In the baseline example, provided above, we are receiving 0.2 Amp/hr or 0.4% of the batteries capacity for the...distribution method, and batteries all impact the amount of power delivered. Careful selection of these components will allow the laser to power

  16. United Nations deliberations of the use of nuclear power sources in space: 1978-1987 (United States)

    Bennett, Gary L.; Sholtis, Joseph A., Jr.; Rashkow, Bruce C.


    The United Nations (U.N.) is continuing its deliberations on the use of nuclear power sources (NPS) in space. Although no complete set of legal principles has yet been agreed upon, certain scientific and technical criteria for the safe design and use of NPS have been accepted. In this respect, it should be noted that in its 1981 report, the Working Group on the Use of Power Sources in Outer Space concluded that power sources can be used safely in outer space, provided that all necessary safety requirements are met. This is also a succinct statement of the U.S. position.

  17. Powering an in-space 3D printer using solar light energy (United States)

    Leake, Skye; McGuire, Thomas; Parsons, Michael; Hirsch, Michael P.; Straub, Jeremy


    This paper describes how a solar power source can enable in-space 3D printing without requiring conversion to electric power and back. A design for an in-space 3D printer is presented, with a particular focus on the power generation system. Then, key benefits are presented and evaluated. Specifically, the approach facilitates the design of a spacecraft that can be built, launched, and operated at very low cost levels. The proposed approach also facilitates easy configuration of the amount of energy that is supplied. Finally, it facilitates easier disposal by removing the heavy metals and radioactive materials required for a nuclear-power solution.

  18. Progress update of NASA's free-piston Stirling space power converter technology project (United States)

    Dudenhoefer, James E.; Winter, Jerry M.; Alger, Donald


    A progress update is presented of the NASA LeRC Free-Piston Stirling Space Power Converter Technology Project. This work is being conducted under NASA's Civil Space Technology Initiative (CSTI). The goal of the CSTI High Capacity Power Element is to develop the technology base needed to meet the long duration, high capacity power requirements for future NASA space initiatives. Efforts are focused upon increasing system power output and system thermal and electric energy conversion efficiency at least five fold over current SP-100 technology, and on achieving systems that are compatible with space nuclear reactors. This paper will discuss progress toward 1050 K Stirling Space Power Converters. Fabrication is nearly completed for the 1050 K Component Test Power Converter (CTPC); results of motoring tests of the cold end (525 K), are presented. The success of these and future designs is dependent upon supporting research and technology efforts including heat pipes, bearings, superalloy joining technologies, high efficiency alternators, life and reliability testing, and predictive methodologies. This paper will compare progress in significant areas of component development from the start of the program with the Space Power Development Engine (SPDE) to the present work on CTPC.

  19. Preparation of All-Ceramic, High Performance Li-ion Batteries for Deep Space Power Systems Project (United States)

    National Aeronautics and Space Administration — Lithium (Li) ion batteries are among the most promising power sources for many civilian, military and space applications due to their high power and high energy...

  20. Power Beaming to Space Using a Nuclear Reactor-Pumped Laser (United States)

    Lipinski, Ronald J.; Monroe, David K.; Pickard, Paul S.


    The present political and environmental climate may slow the inevitable direct utilization of nuclear power in space. In the meantime, there is another approach for using nuclear energy for space power. That approach is to let nuclear energy generate a laser beam in a ground-based nuclear reactor-pumped laser (RPL), and then beam the optical energy into space. Potential space applications for a ground-based RPL include (1) illuminating geosynchronous communication satellites in the earth's shadow to extend their lives, (2) beaming power to orbital transfer vehicles, (3) providing power (from earth) to a lunar base during the long lunar night, and (4) removing space debris. FALCON is a high-power, steady-state, nuclear reactor-pumped laser (RPL) concept which is being developed by the Department of Energy with Sandia National Laboratories as the lead laboratory. The FALCON program has experimentally demonstrated reactor-pumped lasing in various mixtures of xenon, argon, neon, and helium at wavelengths of 585, 703, 725, 1271, 1733, 1792, 2032, 2630, 2650, and 3370 nm with intrinsic efficiency as high as 2.5%. Frequency-doubling the 1733-nm line would yield a good match for photovoltaic arrays at 867 nm. Preliminary designs of an RPL suitable for power beaming have been completed. The MW- class laser is fairly simple in construction, self-powered, closed-cycle (no exhaust gases), and modular. This paper describes the FALCON program accomplishments and power-beaming applications.

  1. Space matters: the relational power of mobile technologies

    Directory of Open Access Journals (Sweden)

    Nancy Odendaal


    Full Text Available The ubiquitous presence of mobile telephony and proliferation of digital networks imply a critical role for these technologies in overcoming the constraints of space in fragmented cities. Academic literature draws from a range of disciplines but fails to address the significance of new technologies for African and South African cities. Debates on technologies and urban spaces reflect a Northern bias and case literature that dwells on the developmental aspects of ICT do not engage with the broader significance with regards to urban change in African cities. This research addresses these gaps by examining the local transformative qualities of mobile telephony in a South African city, Durban. It focuses on the ways in which informal traders active in the city use technology. Actor-network theory was used in the analysis of the field work, uncovering material and human actors, network stabilization processes and agency in determining the transformative potential of this form of digital networking at city and local scales. Findings indicate that appropriation of technology is informed by livelihood strategies. Innovation is enabled when translation extends to appropriation. More in-depth research is needed on how technology is molded and appropriated to suit livelihoods. Throughout the research the spatial dimensions of the relationship between mobile telephony and networks were considered. The network spaces that emerge from actor relations do not correspond with the physical spaces usually considered in policy.

  2. Advanced In-Space Propulsion (AISP): High Temperature Boost Power Processing Unit (PPU) Project (United States)

    National Aeronautics and Space Administration — The task is to investigate the technology path to develop a 10kW modular Silicon Carbide (SiC) based power processing unit (PPU). The PPU utilizes the high...

  3. Benchmark Study and Characterization of European Rad-Hard Power MOSFEts for Space Applications (United States)

    Becherer, J.; Dittrich, R.; Muschitiello, M.; Constantino, A.


    Power Field Effect Transistors are an integral part of the electronic equipment of every space vehicle. In order to survive the harsh conditions of space, the transistors have to fulfill rigorous conditions. A number one in the list of space qualification criteria is the guarantee of radiation hardness. Today several radiation hard Power MOSFETs are available from a variety of companies all over the world. A benchmark study of the available Power MOSFETs for space applications has been compiled in this paper. The newly developed European Superjunction Technologies Power MOSFETs from Infineon show the best performance. Therefore, a total ionizing dose characterization of the 250 V and 150 V European MOSFETs have been performed.

  4. Massey, Doreen, Power-geometries and the politics of space-time / [rezensiert von] Wolfgang Aschauer


    Aschauer, Wolfgang


    Rezensiertes Werk: Power-geometries and the politics of space-time : Hettner-Lecture 1998 / with Doreen Massey. - Heidelberg : Dep. of Geography, Univ., 1999. - 112 S. : Ill. - (Hettner-Lectures ; 2) ISBN 3-88570-502-8

  5. Research Needs: Prime-Power for High Energy Space Systems. (United States)


    34The MHD Disk Generator as a Multimegawatt Power Supply Operating with Chemical and Nuclear Sources" 1. Louis, J. F., "Disk Generator", AIAA J., Vol. VI...May 16-18, 1977. 8. Lytle, J. K. and Louis, J. F., "The Effects of AnisotropicNonuniformities in a Nonequilibrium MHD Disk Generator , presented at

  6. Policy, Influence, And Diplomacy: Space as a National Power Element (United States)


    179 Antonio Gramsci , The Modern Prince & Other Writings (New York: International Publishers, 1967). According to Gramsci , true power is the 1990s. Annapolis, Md.: Naval Institute Press, 1992. Gramsci , Antonio . The Modern Prince & Other Writings. New York: International...Telegraph, Italian Defense Minister Antonio Martino, among others, expressed his desire for proof before Italy would support action against Iraq

  7. In-orbit assembly mission for the Space Solar Power Station (United States)

    Cheng, ZhengAi; Hou, Xinbin; Zhang, Xinghua; Zhou, Lu; Guo, Jifeng; Song, Chunlin


    The Space Solar Power Station (SSPS) is a large spacecraft that utilizes solar power in space to supply power to an electric grid on Earth. A large symmetrical integrated concept has been proposed by the China Academy of Space Technology (CAST). Considering its large scale, the SSPS requires a modular design and unitized general interfaces that would be assembled in orbit. Facilities system supporting assembly procedures, which include a Reusable Heavy Lift Launch Vehicle, orbital transfer and space robots, is introduced. An integrated assembly scheme utilizing space robots to realize this platform SSPS concept is presented. This paper tried to give a preliminary discussion about the minimized time and energy cost of the assembly mission under best sequence and route This optimized assembly mission planning allows the SSPS to be built in orbit rapidly, effectively and reliably.

  8. A study of the effects of effluents on high power space systems (United States)

    Gordon, Lloyd B.

    The author reviews the possible effects of effluents on high-power space platforms located in low earth orbits. High-power/burst-mode space platforms will likely produce copious amounts of effluents during the production of power and the cooling of components. Such effluents can have many detrimental effects on operation of the system, including surface contamination, degradation of sensors and communication, attenuation and scattering of emitted energy or particle beams, and volume and surface high-voltage breakdown. This interaction may cause immediate system failure or gradual degradation. The major effects of effluents upon the operation of high-power/high-energy platforms are discussed, focusing on the interaction of large-scale effluents with electric power components. Space experiments are proposed to study effluent-system interactions.

  9. Air & Space Power Journal. Volume 19, Number 1, Spring 2005 (United States)


    inbound anti- radiation missile, and the Patriot battery fired in self-defense.11 A similar incident occurred less than 24 hours later. A flight...complaining about the food but never chal­ lenging the authorities who sent them there. This reporting was a far cry from that done by “ hotel­ mercially viable for tourism and extensive research and, soon thereafter, for commercial applications (some not yet thought of). Imagine a space

  10. An interconnecting bus power optimization method combining interconnect wire spacing with wire ordering

    Institute of Scientific and Technical Information of China (English)

    Zhu Zhang-Ming; Hao Bao-Tian; En Yun-Fei; Yang Yin-Tang; Li Yue-Jin


    On-chip interconnect buses consume tens of percents of dynamic power in a nanometer scale integrated circuit and they will consume more power with the rapid scaling down of technology size and continuously rising clock frequency,therefore it is meaningful to lower the interconnecting bus power in design. In this paper, a simple yet accurate interconnect parasitic capacitance model is presented first and then, based on this model, a novel interconnecting bus optimization method is proposed. Wire spacing is a process for spacing wires for minimum dynamic power, while wire ordering is a process that searches for wire orders that maximally enhance it. The method, i.e., combining wire spacing with wire ordering, focuses on bus dynamic power optimization with a consideration of bus performance requirements.The optimization method is verified based on various nanometer technology parameters, showing that with 50% slack of routing space, 25.71% and 32.65% of power can be saved on average by the proposed optimization method for a globalbus and an intermediate bus, respectively, under a 65-nm technology node, compared with 21.78% and 27.68% of power saved on average by uniform spacing technology. The proposed method is especially suitable for computer-aided designof nanometer scale on-chip buses.

  11. Next generation power electronics for space and aircraft. II - Packaging (United States)

    Iversen, Arthur

    A class of semiconductor packaging incorporating a novel type of heat exchange process is described. The packaging technology is characterized by high power density, 0.005 kg/kW with beryllium construction, low junction to fluid specific thermal resistance 0.1-0.3 C/W(sq cm) for lower junction temperatures, and consequent improved reliability and increased efficiency, and rugged, hermetic, and low-cost construction. A curved surface cooling technology is incorporated into several package designs. Initial experiments with curved surface cooling have demonstrated a dissipation of 472 W/sq cm at rated junction temperature (150 C) for power MOSFETs. More important for high-reliability and high-efficiency applications is the demonstrated 60 C junction temperature at 200 W/sq cm dissipation. The packaging technology is substantially device transparent.

  12. Light weight space power reactors for nuclear electric propulsion

    Energy Technology Data Exchange (ETDEWEB)

    Ludewig, H.; Mughabghab, S.; Lazareth, O.; Perkins, K.; Schmidt, E.; Powell, J.R.


    A Nuclear Electric Propulsion (NEP) unit capable of propelling a manned vehicle to MARS will be required to have a value of {alpha} (kg/kWe) which is less than five. In order to meet this goal the reactor mass, and thus its contribution to the value of {alpha} will have to be minimized. In this paper a candidate for such a reactor is described. It consists of a gas cooled Particle Bed Reactor (PBR), with specially chosen materials which allow it to operate at an exit temperature of approximately 2000 K. One of the unique features of a PBR is the direct cooling of particulate fuel by the working fluid. This feature allows for high power densities, highest possible gas exit temperatures, for a given fuel temperature and because of the thin particle bed a low pressure drop. The PBR's described in this paper will have a ceramic moderator (Be{sub 2}C), ZrC coated fuel particles and a carbon/carbon hot frit. All the reactors will be designed with sufficient fissile loading to operate at full power for seven years. The burn up possible with particulate fuel is approximately 30%--50%. These rector designs achieve a value of {alpha} less than unity in the power range of interest (5 MWe). 5 refs., 3 figs.

  13. Higher (2nd)-order polarization-Wigner function for `even' entangled bi-modal coherent states

    CERN Document Server

    Singh, Ravi S; Yadava, Lallan; Gupta, Gyaneshwar K


    Higher (2nd)-order Wigner distribution function in quantum phase space for entangled bi-modal coherent states, a representative of higher (2nd)-order optical-polarization, is introduced by generalizing kernel (transiting) operator in Cahill-Glauber C(s)-correspondence rule. The nature is analyzed which reveals the occurrence of oscillating three peaks: 'two' for individual bi-modes and third for interference between modes. Also, the graphics of 2nd-order polarization-Wigner distribution function, incisively, demonstrates that it is of non-Gaussian nature attaining non-negative values in quantum phase space.

  14. Space-based Solar Power: Possible Defense Applications and Opportunities for NRL Contributions (United States)


    converter, solid state driver, and TWT power amplifier). Widely deployed in military systems and space qualified . • GaN HEMT: 80 W, 60% efficiency...240-m rims rotate about this axis to track the Sun. The Mantech SRS reflectors are of space - qualified polyimide with 94% reflectivity and an NRL...0.1-0.3 65 - 75 Space qualified , relatively compact, moderately expensive Magnetron 0.5-5 75 - 85 Inexpensive, compact, phase controllable GaN SSPA

  15. Differential topological characteristics of the DSR on injection space of electrical power system

    Institute of Scientific and Technical Information of China (English)

    余贻鑫; 曾沅; 冯飞


    This paper analyzes the differential topological characteristics of the dynamic security region (DSR) on injection space of electrical power system by differential topology theories. It is shown that the boundary of the DSR on injection space has no suspension and is compact, and there are no holes inside the DSR defined based on controlling unstable equilibrium point (UEP) method. The 10-generator, 39-bus New England Test System, is taken as an example to show these characteristics of the DSR on injection space.

  16. Active and reactive power control of a current-source PWM-rectifier using space vectors

    Energy Technology Data Exchange (ETDEWEB)

    Salo, M.; Tuusa, H. [Tampere University of Technology (Finland). Department of Electrical Engineering, Power Electronics


    In this paper the current-source PWM-rectifier with active and reactive power control is presented. The control system is realized using space vector methods. Also, compensation of the reactive power drawn by the line filter is discussed. Some simulation results are shown. (orig.) 8 refs.

  17. Power monitoring in space nuclear reactors using silicon carbide radiation detectors (United States)

    Ruddy, Frank H.; Patel, Jagdish U.; Williams, John G.


    Space reactor power monitors based on silicon carbide (SiC) semiconductor neutron detectors are proposed. Detection of fast leakage neutrons using SiC detectors in ex-core locations could be used to determine reactor power: Neutron fluxes, gamma-ray dose rates and ambient temperatures have been calculated as a function of distance from the reactor core, and the feasibility of power monitoring with SiC detectors has been evaluated at several ex-core locations. Arrays of SiC diodes can be configured to provide the required count rates to monitor reactor power from startup to full power Due to their resistance to temperature and the effects of neutron and gamma-ray exposure, SiC detectors can be expected to provide power monitoring information for the fill mission of a space reactor.

  18. Power Supplies for Space Systems Quality Assurance by Sandia Laboratories (United States)

    Hannigan, R. L.; Harnar, R. R.


    The Sandia Laboratories` participation in Quality Assurance programs for Radioisotopic Thermoelectric Generators which have been used in space systems over the past 10 years is summarized. Basic elements of this QA program are briefly described and recognition of assistance from other Sandia organizations is included. Descriptions of the various systems for which Sandia has had the QA responsibility are presented, including SNAP 19 (Nimbus, Pioneer, Viking), SNAP 27 (Apollo), Transit, Multi Hundred Watt (LES 8/9 and MJS), and a new program, High Performance Generator Mod 3. The outlook for Sandia participation in RTG programs for the next several years is noted.

  19. Structural Stability of Planar Bimodal Linear Systems

    Directory of Open Access Journals (Sweden)

    Josep Ferrer


    Full Text Available Structural stability ensures that the qualitative behavior of a system is preserved under small perturbations. We study it for planar bimodal linear dynamical systems, that is, systems consisting of two linear dynamics acting on each side of a given hyperplane and assuming continuity along the separating hyperplane. We describe which one of these systems is structurally stable when (real spiral does not appear and when it does we give necessary and sufficient conditions concerning finite periodic orbits and saddle connections. In particular, we study the finite periodic orbits and the homoclinic orbits in the saddle/spiral case.

  20. New vision solar system exploration missions study: Analysis of the use of biomodal space nuclear power systems to support outer solar system exploration missions. Final report

    Energy Technology Data Exchange (ETDEWEB)



    This report presents the results of an analysis of the capability of nuclear bimodal systems to perform outer solar system exploration missions. Missions of interest include orbiter mission s to Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto. An initial technology baseline consisting of a NEBA 10 kWe, 1000 N thrust, 850 s, 1500 kg bimodal system was selected, and its performance examined against a data base for trajectories to outer solar system planetary destinations to select optimal direct and gravity assisted trajectories for study. A conceptual design for a common bimodal spacecraft capable of performing missions to all the planetary destinations was developed and made the basis of end to end mission designs for orbiter missions to Jupiter, Saturn, and Neptune. Concepts for microspacecraft capable of probing Jupiter`s atmosphere and exploring Titan were also developed. All mission designs considered use the Atlas 2AS for launch. It is shown that the bimodal nuclear power and propulsion system offers many attractive option for planetary missions, including both conventional planetary missions in which all instruments are carried by a single primary orbiting spacecraft, and unconventional missions in which the primary spacecraft acts as a carrier, relay, and mother ship for a fleet of micro spacecraft deployed at the planetary destination.

  1. Technology development for nuclear power generation for space application

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, Lamartine N.F.; Ribeiro, Guilherme B.; Braz Filho, Francisco A.; Nascimento, Jamil A.; Placco, Guilherme M., E-mail:, E-mail: [Instituto de Estudos Avancados (IEAv), Sao Jose dos Campos, SP (Brazil). Divisao de Energia Nuclear; Faria, Saulo M. de [Instituto Tecnologico de Aeronautica (ITA), Sao Jose dos Campos, SP (Brazil)


    For a few years now, the TERRA project is developing several technology pieces to foster nuclear space applications. In this way, a nuclear reactor concept has been developed as a first proposal. Together, the problem of heat to electricity conversion has been addressed. A closed Brayton cycle is being built and a Stirling machine is being worked out and perfected. In addition, two types of heat pipes are being look at. One related with high temperature made of Mo13Re, an especial alloy. And a second one made of copper, which mainly could be used as a passive heat rejection. In this way, all major areas of interest in a micro station to be used in space has been addressed. A new passive technology has been inferred and is related with Tesla turbine or its evolution, known as multi fluid passive turbine. This technology has the potential to either: improve the Brayton cycle or its efficiency. In this paper, some details are discussed and some will be shown during the presentation, as the work evolve. (author)

  2. Power Line Communication (PLC) in Space - Current Status and Outlook (United States)

    Wolf, J.


    The Power Line Communication (PLC) technology as known from various terrestrial applications, e.g. in building automation, in the automotive sector and on aircraft, appears to be a promising technology for the use on spacecraft. Starting from a critical overview on existing terrestrial PLC applications with their pros and cons, the paper gives a motivation for the introduction of the PLC technology on spacecraft, discusses the potential areas where it can be applied and is highlighting the potential problem areas. A short overview of on-going ESA PLC activities is provided and an outlook is given.

  3. The Need for Intelligent Control of Space Power Systems (United States)

    May, Ryan David; Soeder, James F.; Beach, Raymond F.; McNelis, Nancy B.


    As manned spacecraft venture farther from Earth, the need for reliable, autonomous control of vehicle subsystems becomes critical. This is particularly true for the electrical power system which is critical to every other system. Autonomy can not be achieved by simple scripting techniques due to the communication latency times and the difficulty associated with failures (or combinations of failures) that need to be handled in as graceful a manner as possible to ensure system availability. Therefore an intelligent control system must be developed that can respond to disturbances and failures in a robust manner and ensure that critical system loads are served and all system constraints are respected.

  4. Automating security monitoring and analysis for Space Station Freedom's electric power system (United States)

    Dolce, James L.; Sobajic, Dejan J.; Pao, Yoh-Han


    Operating a large, space power system requires classifying the system's status and analyzing its security. Conventional algorithms are used by terrestrial electric utilities to provide such information to their dispatchers, but their application aboard Space Station Freedom will consume too much processing time. A novel approach for monitoring and analysis using adaptive pattern techniques is presented. This approach yields an on-line security monitoring and analysis algorithm that is accurate and fast; and thus, it can free the Space Station Freedom's power control computers for other tasks.

  5. Electromagnetic and acoustic bimodality for the detection and localization of electrical arc faults (United States)

    Vasile, C.; Ioana, C.; Digulescu, A.; Candel, I.


    Electrical arc faults pose an important problem to electrical installations worldwide, be it production facilities or distribution systems. In this context, it is easy to assess the economic repercussions of such a fault, when power supply is cut off downstream of its location, while also realizing that an early detection of the on-site smaller scale faults would be of great benefit. This articles serves as a review of the current state-of-the-art work that has been carried out on the subject of detection and localization of electrical arc faults, by exploiting the bimodality of this phenomenon, which generates simultaneously electromagnetic and acoustic waves, propagating in a free space path. En experimental setup has been defined, to demonstrate principles stated in previous works by the authors, and signal processing methods have been used in order to determine the DTOA (difference-of-time-of-arrival) of the acoustic signals, which allows localization of the transient fault. In the end there is a discussion regarding the results and further works, which aims to validate this approach in more real-life applications.

  6. A high power lithium thionyl chloride battery for space applications (United States)

    Shah, Pinakin M.


    A high power, 28 V, 330 A h, active lithium thionyl chloride battery has been developed for use as main and payload power sources on an expendable launch vehicle. Nine prismatic cells, along with the required electrical components and a built-in heater system, are efficiently packaged resulting in significant weight savings over presently used silver-zinc batteries. The high rate capability is achieved by designing the cells with a large electrochemical surface area and impregnating an electrocatalyst, polymeric phthalocyanine, into the carbon cathodes. Passivation effects are reduced with the addition of sulfur dioxide into the thionyl chloride electrolyte solution. The results of conducting a detailed thermal analysis are utilized to establish the heater design parameters and the thermal insulation requirements of the battery. An analysis of cell internal pressure and vent characteristics clearly illustrates the margins of safety under different operating conditions. Performance of fresh cells is discussed using polarization scan and discharge data at different rates and temperatures. Self-discharge rate is estimated based upon test results on cells after storage. Results of testing a complete prototype battery are described.

  7. Influence and hazard of disastrous space weather on power grid in China%Influence and hazard of disastrous space weather on power grid in China

    Institute of Scientific and Technical Information of China (English)

    Liu Lianguang; Zheng Kuan; Liu Chunming


    Based on the measured data of geomagnetically induced currents (GIC) in Guangdong Ling' ao 500 kV power networks during several magnetic storms at the peak years of 23rd Solar Cycle, the GIC calculation results of 750 kV planning power grid in Shartxi, Gansu, Qinghai and Ningxia, the structure and characteristics of power networks from 500 kV to 1 000 kV, and super magnetic storm in 1859 are analyzed in this paper. Through the analysis, the possible impacts of extreme space weather on the future ultra-high voltage (UHV) grid, the security of large-scale power system in China are expounded, and the research suggestions coping with the strong solar storms are proposed.

  8. Lightweight Inflatable Solar Array: Providing a Flexible, Efficient Solution to Space Power Systems for Small Spacecraft (United States)

    Johnson, Len; Fabisinski, Leo; Cunningham, Karen; Justice, Stefanie


    Affordable and convenient access to electrical power is critical to consumers, spacecraft, military and other applications alike. In the aerospace industry, an increased emphasis on small satellite flights and a move toward CubeSat and NanoSat technologies, the need for systems that could package into a small stowage volume while still being able to power robust space missions has become more critical. As a result, the Marshall Space Flight Center's Advanced Concepts Office identified a need for more efficient, affordable, and smaller space power systems to trade in performing design and feasibility studies. The Lightweight Inflatable Solar Array (LISA), a concept designed, prototyped, and tested at the NASA Marshall Space Flight Center (MSFC) in Huntsville, Alabama provides an affordable, lightweight, scalable, and easily manufactured approach for power generation in space or on Earth. This flexible technology has many wide-ranging applications from serving small satellites to soldiers in the field. By using very thin, ultraflexible solar arrays adhered to an inflatable structure, a large area (and thus large amount of power) can be folded and packaged into a relatively small volume (shown in artist rendering in Figure 1 below). The proposed presentation will provide an overview of the progress to date on the LISA project as well as a look at its potential, with continued development, to revolutionize small spacecraft and portable terrestrial power systems.

  9. NASA solar dynamic ground test demonstration (GTD) program and its application to space nuclear power (United States)

    Harper, William B.; Shaltens, Richard K.


    Closed Brayton cycle power conversion systems are readily adaptable to any heat source contemplated for space application. The inert gas working fluid can be used directly in gas-cooled reactors and coupled to a variety of heat sources (reactor, isotope or solar) by a heat exchanger. This point is demonstrated by the incorporation in the NASA 2 kWe Solar Dynamic (SD) Space Power Ground Test Demonstration (GTD) Program of the turboalternator-compressor and recuperator from the Brayton Isotope Power System (BIPS) program. This paper will review the goals and status of the SD GTD Program, initiated in April 1992. The performance of the BIPS isotope-heated system will be compared to the solar-heated GTD system incorporating the BIPS components and the applicability of the GTD test bed to dynamics space nuclear power R&D will be discussed.

  10. NASA's PEM Fuel Cell Power Plant Development Program for Space Applications (United States)

    Hoberecht, Mark A.


    A three-center NASA team led by the Glenn Research Center in Cleveland, Ohio is completing a five-year PEM fuel cell power plant development program for future space applications. The focus of the program has been to adapt commercial PEM fuel cell technology for space applications by addressing the key mission requirements of using pure oxygen as an oxidant and operating in a multi-gravity environment. Competing vendors developed breadboard units in the 1 to 5 kW power range during the first phase of the program, and a single vendor developed a nominal 10-kW engineering model power pant during the second phase of the program. Successful performance and environmental tests conducted by NASA established confidence that PEM fuel cell technology will be ready to meet the electrical power needs of future space missions.

  11. Penetration in bimodal, polydisperse granular material

    KAUST Repository

    Kouraytem, N.


    We investigate the impact penetration of spheres into granular media which are compositions of two discrete size ranges, thus creating a polydisperse bimodal material. We examine the penetration depth as a function of the composition (volume fractions of the respective sizes) and impact speed. Penetration depths were found to vary between delta = 0.5D(0) and delta = 7D(0), which, for mono-modal media only, could be correlated in terms of the total drop height, H = h + delta, as in previous studies, by incorporating correction factors for the packing fraction. Bimodal data can only be collapsed by deriving a critical packing fraction for each mass fraction. The data for the mixed grains exhibit a surprising lubricating effect, which was most significant when the finest grains [d(s) similar to O(30) mu m] were added to the larger particles [d(l) similar to O(200 - 500) mu m], with a size ratio, epsilon = d(l)/d(s), larger than 3 and mass fractions over 25%, despite the increased packing fraction. We postulate that the small grains get between the large grains and reduce their intergrain friction, only when their mass fraction is sufficiently large to prevent them from simply rattling in the voids between the large particles. This is supported by our experimental observations of the largest lubrication effect produced by adding small glass beads to a bed of large sand particles with rough surfaces.

  12. On the Bimodality of ENSO Cycle Extremes (United States)

    Wilson, Robert M.


    On the basis of sea surface temperature in the Nino 3.4 region (5 deg N-5 deg S, 120 deg- 170 deg W) during the interval of 1950-1997, Kevin Trenberth previously has identified some 16 El Nino and 10 La Nina, these 26 events representing the extremes of the quasi-periodic El Nino-Southern Oscillation (ENSO) cycle. Runs testing shows that the duration and recurrence period associated with these extremes vary randomly, as does the sequencing of the extremes. Hence, the frequency of occurrence of these events during the 1990s, especially, for El Nino should not be construed as being significantly different from that of previous epochs. Additionally, the distribution of duration for both El Nino and La Nina looks bimodal, consisting of two preferred modes - about 8 and 16 months in length for El Nino and about 9 and 18 months in length for La Nina. Likewise, the distribution of recurrence period, especially, for El Nino looks bimodal, consisting of two preferred modes - about 21 and 50 months in length. Scatter plots of the recurrence period versus duration for El Nino strongly suggest preferential associations between them, linking shorter (longer) duration with shorter (longer) recurrence period. Because the last known onset of El Nino occurred in April 1997 and the event was of longer than average duration, one infers that the onset of the next expected El Nino will not occur until February 2000 or later.

  13. Penetration in bimodal, polydisperse granular material (United States)

    Kouraytem, N.; Thoroddsen, S. T.; Marston, J. O.


    We investigate the impact penetration of spheres into granular media which are compositions of two discrete size ranges, thus creating a polydisperse bimodal material. We examine the penetration depth as a function of the composition (volume fractions of the respective sizes) and impact speed. Penetration depths were found to vary between δ =0.5 D0 and δ =7 D0 , which, for mono-modal media only, could be correlated in terms of the total drop height, H =h +δ , as in previous studies, by incorporating correction factors for the packing fraction. Bimodal data can only be collapsed by deriving a critical packing fraction for each mass fraction. The data for the mixed grains exhibit a surprising lubricating effect, which was most significant when the finest grains [ds˜O (30 ) μ m ] were added to the larger particles [dl˜O (200 -500 ) μ m ] , with a size ratio, ɛ =dl/ds , larger than 3 and mass fractions over 25%, despite the increased packing fraction. We postulate that the small grains get between the large grains and reduce their intergrain friction, only when their mass fraction is sufficiently large to prevent them from simply rattling in the voids between the large particles. This is supported by our experimental observations of the largest lubrication effect produced by adding small glass beads to a bed of large sand particles with rough surfaces.

  14. Bimodal Color Distribution in Hierarchical Galaxy Formation

    CERN Document Server

    Menci, N; Giallongo, E; Salimbeni, S


    We show how the observed bimodality in the color distribution of galaxies can be explained in the framework of the hierarchical clustering picture in terms of the interplay between the properties of the merging histories and the feedback/star-formation processes in the progenitors of local galaxies. Using a semi-analytic model of hierarchical galaxy formation, we compute the color distributions of galaxies with different luminosities and compare them with the observations. Our fiducial model matches the fundamental properties of the observed distributions, namely: 1) the distribution of objects brighter than M_r = -18 is clearly bimodal, with a fraction of red objects increasing with luminosity; 2) for objects brighter than M_r = -21 the color distribution is dominated by red objects with color u-r = 2.2-2.4; 3) the spread on the distribution of the red population is smaller than that of the blue population; 4) the fraction of red galaxies is larger in denser environments, even for low-luminosity objects; 5) ...

  15. Globular Cluster Systems in Brightest Cluster Galaxies. III: Beyond Bimodality (United States)

    Harris, William E.; Ciccone, Stephanie M.; Eadie, Gwendolyn M.; Gnedin, Oleg Y.; Geisler, Douglas; Rothberg, Barry; Bailin, Jeremy


    We present new deep photometry of the rich globular cluster (GC) systems around the Brightest Cluster Galaxies UGC 9799 (Abell 2052) and UGC 10143 (Abell 2147), obtained with the Hubble Space Telescope (HST) ACS and WFC3 cameras. For comparison, we also present new reductions of similar HST/ACS data for the Coma supergiants NGC 4874 and 4889. All four of these galaxies have huge cluster populations (to the radial limits of our data, comprising from 12,000 to 23,000 clusters per galaxy). The metallicity distribution functions (MDFs) of the GCs can still be matched by a bimodal-Gaussian form where the metal-rich and metal-poor modes are separated by ≃ 0.8 dex, but the internal dispersions of each mode are so large that the total MDF becomes very broad and nearly continuous from [Fe/H] ≃ ‑2.4 to solar. There are, however, significant differences between galaxies in the relative numbers of metal-rich clusters, suggesting that they underwent significantly different histories of mergers with massive gas-rich halos. Last, the proportion of metal-poor GCs rises especially rapidly outside projected radii R≳ 4 {R}{eff}, suggesting the importance of accreted dwarf satellites in the outer halo. Comprehensive models for the formation of GCs as part of the hierarchical formation of their parent galaxies will be needed to trace the systematic change in structure of the MDF with galaxy mass, from the distinctly bimodal form in smaller galaxies up to the broad continuum that we see in the very largest systems.

  16. The Bimodality Index: A Criterion for Discovering and Ranking Bimodal Signatures from Cancer Gene Expression Profiling Data

    Directory of Open Access Journals (Sweden)

    Jing Wang


    Full Text Available Motivation: Identifying genes with bimodal expression patterns from large-scale expression profiling data is an important analytical task. Model-based clustering is popular for this purpose. That technique commonly uses the Bayesian information criterion (BIC for model selection. In practice, however, BIC appears to be overly sensitive and may lead to the identification of bimodally expressed genes that are unreliable or not clinically useful. We propose using a novel criterion, the bimodality index, not only to identify but also to rank meaningful and reliable bimodal patterns. The bimodality index can be computed using either a mixture model-based algorithm or Markov chain Monte Carlo techniques.Results: We carried out simulation studies and applied the method to real data from a cancer gene expression profiling study. Our findings suggest that BIC behaves like a lax cutoff based on the bimodality index, and that the bimodality index provides an objective measure to identify and rank meaningful and reliable bimodal patterns from large-scale gene expression datasets. R code to compute the bimodality index is included in the ClassDiscovery package of the Object-Oriented Microarray and Proteomic Analysis (OOMPA suite available at the web site

  17. A Crewed Mission to Apophis Using a Hybrid Bimodal Nuclear Thermal Electric Propulsion (BNTEP) System (United States)

    Mccurdy, David R.; Borowski, Stanley K.; Burke, Laura M.; Packard, Thomas W.


    A BNTEP system is a dual propellant, hybrid propulsion concept that utilizes Bimodal Nuclear Thermal Rocket (BNTR) propulsion during high thrust operations, providing 10's of kilo-Newtons of thrust per engine at a high specific impulse (Isp) of 900 s, and an Electric Propulsion (EP) system during low thrust operations at even higher Isp of around 3000 s. Electrical power for the EP system is provided by the BNTR engines in combination with a Brayton Power Conversion (BPC) closed loop system, which can provide electrical power on the order of 100's of kWe. High thrust BNTR operation uses liquid hydrogen (LH2) as reactor coolant propellant expelled out a nozzle, while low thrust EP uses high pressure xenon expelled by an electric grid. By utilizing an optimized combination of low and high thrust propulsion, significant mass savings over a conventional NTR vehicle can be realized. Low thrust mission events, such as midcourse corrections (MCC), tank settling burns, some reaction control system (RCS) burns, and even a small portion at the end of the departure burn can be performed with EP. Crewed and robotic deep space missions to a near Earth asteroid (NEA) are best suited for this hybrid propulsion approach. For these mission scenarios, the Earth return V is typically small enough that EP alone is sufficient. A crewed mission to the NEA Apophis in the year 2028 with an expendable BNTEP transfer vehicle is presented. Assembly operations, launch element masses, and other key characteristics of the vehicle are described. A comparison with a conventional NTR vehicle performing the same mission is also provided. Finally, reusability of the BNTEP transfer vehicle is explored.

  18. PC Software graphics tool for conceptual design of space/planetary electrical power systems (United States)

    Truong, Long V.


    This paper describes the Decision Support System (DSS), a personal computer software graphics tool for designing conceptual space and/or planetary electrical power systems. By using the DSS, users can obtain desirable system design and operating parameters, such as system weight, electrical distribution efficiency, and bus power. With this tool, a large-scale specific power system was designed in a matter of days. It is an excellent tool to help designers make tradeoffs between system components, hardware architectures, and operation parameters in the early stages of the design cycle. The DSS is a user-friendly, menu-driven tool with online help and a custom graphical user interface. An example design and results are illustrated for a typical space power system with multiple types of power sources, frequencies, energy storage systems, and loads.

  19. Mapping of error cells in clinical measure to symmetric power space. (United States)

    Abelman, H; Abelman, S


    During the refraction procedure, the power of the nearest equivalent sphere lens, known as the scalar power, is conserved within upper and lower bounds in the sphere (and cylinder) lens powers. Bounds are brought closer together while keeping the circle of least confusion on the retina. The sphere and cylinder powers and changes in these powers are thus dependent. Changes are depicted in the cylinder-sphere plane by error cells with one pair of parallel sides of negative gradient and the other pair aligned with the graph axis of cylinder power. Scalar power constitutes a vector space, is a meaningful ophthalmic quantity and is represented by the semi-trace of the dioptric power matrix. The purpose of this article is to map to error cells for the following: coordinates of the dioptric power matrix, its principal powers and meridians and its entries from error cells surrounding powers in sphere, cylinder and axis. Error cells in clinical measure for conserved scalar power now contain more compensatory lens powers. Such cells and their respective mappings in terms of most scientific and alternate clinical quantities now image consistently not only to the cells from where they originate but also to each other.

  20. A high power ion thruster for deep space missions (United States)

    Polk, James E.; Goebel, Dan M.; Snyder, John S.; Schneider, Analyn C.; Johnson, Lee K.; Sengupta, Anita


    The Nuclear Electric Xenon Ion System ion thruster was developed for potential outer planet robotic missions using nuclear electric propulsion (NEP). This engine was designed to operate at power levels ranging from 13 to 28 kW at specific impulses of 6000-8500 s and for burn times of up to 10 years. State-of-the-art performance and life assessment tools were used to design the thruster, which featured 57-cm-diameter carbon-carbon composite grids operating at voltages of 3.5-6.5 kV. Preliminary validation of the thruster performance was accomplished with a laboratory model thruster, while in parallel, a flight-like development model (DM) thruster was completed and two DM thrusters fabricated. The first thruster completed full performance testing and a 2000-h wear test. The second successfully completed vibration tests at the full protoflight levels defined for this NEP program and then passed performance validation testing. The thruster design, performance, and the experimental validation of the design tools are discussed in this paper.

  1. High power free space optical link for rapid energy and data transmission (United States)

    Dhadwal, Harbans S.; Rastegar, Jahangir; Feng, Dake; Kwok, Philip


    Design and experimental data for a high power laser diode based free space point-to-point optical power/data link is presented. In time critical power up applications, such as providing power and guidance information to a munition shell just prior to deployment, energy of the order of 100 J needs to be transferred in under 10 s. Current inductive technology is slow and broadcasts a radio-frequency signal which is undesirable for stealth operation. Rapid energy transfer times require high irradiance levels at the surface of the photovoltaic cells, typically, exceeding 1000X suns. Through efficient thermal design of heat sinks, high optical to electrical power conversion efficiencies of 50%, which are usually attainable at low power levels of 1 W, are achievable at higher power levels.

  2. Fabric composite radiators for space nuclear power applications. Final report, March 1993

    Energy Technology Data Exchange (ETDEWEB)

    Klein, A.C.; Al-Baroudi, H.; Gulshan-Ara, Z.; Kiestler, W.C.; Snuggerud, R.D.; Abdul-Hamid, S.A.; Marks, T.S.


    Nuclear power systems will be required to provide much greater power levels for both civilian and defense space activities in the future than an currently needed. Limitations on the amount of usable power from radioisotope thermal generators and the limited availability of radioisotope heat source materials lead directly to the conclusion that nuclear power reactors will be needed to enhance the exploration of the solar system as well as to provide for an adequate defense. Lunar bases and travel to the Martian surface will be greatly enhanced by the use of high levels of nuclear power. Space based radar systems requiring many kilowatts of electrical power can provide intercontinental airline traffic control and defense early warning systems. Since the, figure of merit used in defining any space power system is the specific power, the decrease in die mass of any reactor system component will yield a tremendous benefit to the overall system performance. Also, since the heat rejection system of any power system can make up a large portion of the total system mass, any reduction in the mass of the heat rejection radiators will significantly affect the performance of the power system. Composite materials which combine the high strength, flexibility, and low mass characteristics of Si% based fibers with the attractive compatibility and heat transfer features of metallic foils, have been proposed for use m a number of space radiator applications. Thus, the weave of the fabric and the high strength capability of the individual fibers are combined with the high conductivity and chemical stability of a metallic liner to provide a light weight, flexible alternative to heavy, rigid, metallic radiator structural containers. The primary focus of this investigation revolves around two applications of the fabric composite materials, notably a fabric heat pipe radiator design and the Bubble Membrane Radiator concept.

  3. Methodolgy For Evaluation Of Technology Impacts In Space Electric Power Systems (United States)

    Holda, Julie


    The Analysis and Management branch of the Power and Propulsion Office at NASA Glenn Research Center is responsible for performing complex analyses of the space power and In-Space propulsion products developed by GRC. This work quantifies the benefits of the advanced technologies to support on-going advocacy efforts. The Power and Propulsion Office is committed to understanding how the advancement in space technologies could benefit future NASA missions. They support many diverse projects and missions throughout NASA as well as industry and academia. The area of work that we are concentrating on is space technology investment strategies. Our goal is to develop a Monte-Carlo based tool to investigate technology impacts in space electric power systems. The framework is being developed at this stage, which will be used to set up a computer simulation of a space electric power system (EPS). The outcome is expected to be a probabilistic assessment of critical technologies and potential development issues. We are developing methods for integrating existing spreadsheet-based tools into the simulation tool. Also, work is being done on defining interface protocols to enable rapid integration of future tools. Monte Carlo-based simulation programs for statistical modeling of the EPS Model. I decided to learn and evaluate Palisade's @Risk and Risk Optimizer software, and utilize it's capabilities for the Electric Power System (EPS) model. I also looked at similar software packages (JMP, SPSS, Crystal Ball, VenSim, Analytica) available from other suppliers and evaluated them. The second task was to develop the framework for the tool, in which we had to define technology characteristics using weighing factors and probability distributions. Also we had to define the simulation space and add hard and soft constraints to the model. The third task is to incorporate (preliminary) cost factors into the model. A final task is developing a cross-platform solution of this framework.

  4. Space and Power in the Ivory Tower: Effective Space Management and Decision Making (United States)

    Blanchette, Sandra


    At a time when there are enormous economic pressures on campuses to use resources effectively, space being one of these resources, the academic culture of shared governance, with its fragmented roles for decision making, presents additional challenges. These roles are fragmented due to independent faculty and administrative action. They are…

  5. A One-year, Short-Stay Crewed Mars Mission Using Bimodal Nuclear Thermal Electric Propulsion (BNTEP) - A Preliminary Assessment (United States)

    Burke, Laura A.; Borowski, Stanley K.; McCurdy, David R.; Packard, Thomas W.


    A crewed mission to Mars poses a signi cant challenge in dealing with the physiolog- ical issues that arise with the crew being exposed to a near zero-gravity environment as well as signi cant solar and galactic radiation for such a long duration. While long sur- face stay missions exceeding 500 days are the ultimate goal for human Mars exploration, short round trip, short surface stay missions could be an important intermediate step that would allow NASA to demonstrate technology as well as study the physiological e ects on the crew. However, for a 1-year round trip mission, the outbound and inbound hy- perbolic velocity at Earth and Mars can be very large resulting in a signi cant propellant requirement for a high thrust system like Nuclear Thermal Propulsion (NTP). Similarly, a low thrust Nuclear Electric Propulsion (NEP) system requires high electrical power lev- els (10 megawatts electric (MWe) or more), plus advanced power conversion technology to achieve the lower speci c mass values needed for such a mission. A Bimodal Nuclear Thermal Electric Propulsion (BNTEP) system is examined here that uses three high thrust Bimodal Nuclear Thermal Rocket (BNTR) engines allowing short departure and capture maneuvers. The engines also generate electrical power that drives a low thrust Electric Propulsion (EP) system used for ecient interplanetary transit. This combined system can help reduce the total launch mass, system and operational requirements that would otherwise be required for equivalent NEP or Solar Electric Propulsion (SEP) mission. The BNTEP system is a hybrid propulsion concept where the BNTR reactors operate in two separate modes. During high-thrust mode operation, each BNTR provides 10's of kilo- Newtons of thrust at reasonably high speci c impulse (Isp) of 900 seconds for impulsive trans-planetary injection and orbital insertion maneuvers. When in power generation / EP mode, the BNTR reactors are coupled to a Brayton power conversion system allowing each

  6. A One-year, Short-Stay Crewed Mars Mission Using Bimodal Nuclear Thermal Electric Propulsion (BNTEP) - A Preliminary Assessment (United States)

    Burke, Laura M.; Borowski, Stanley K.; McCurdy, David R.; Packard, Thomas W.


    A crewed mission to Mars poses a significant challenge in dealing with the physiological issues that arise with the crew being exposed to a near zero-gravity environment as well as significant solar and galactic radiation for such a long duration. While long surface stay missions exceeding 500 days are the ultimate goal for human Mars exploration, short round trip, short surface stay missions could be an important intermediate step that would allow NASA to demonstrate technology as well as study the physiological effects on the crew. However, for a 1-year round trip mission, the outbound and inbound hyperbolic velocity at Earth and Mars can be very large resulting in a significant propellant requirement for a high thrust system like Nuclear Thermal Propulsion (NTP). Similarly, a low thrust Nuclear Electric Propulsion (NEP) system requires high electrical power levels (10 megawatts electric (MWe) or more), plus advanced power conversion technology to achieve the lower specific mass values needed for such a mission. A Bimodal Nuclear Thermal Electric Propulsion (BNTEP) system is examined here that uses three high thrust Bimodal Nuclear Thermal Rocket (BNTR) engines allowing short departure and capture maneuvers. The engines also generate electrical power that drives a low thrust Electric Propulsion (EP) system used for efficient interplanetary transit. This combined system can help reduce the total launch mass, system and operational requirements that would otherwise be required for equivalent NEP or Solar Electric Propulsion (SEP) mission. The BNTEP system is a hybrid propulsion concept where the BNTR reactors operate in two separate modes. During high-thrust mode operation, each BNTR provides 10's of kilo-Newtons of thrust at reasonably high specific impulse (Isp) of 900 seconds for impulsive transplanetary injection and orbital insertion maneuvers. When in power generation/EP mode, the BNTR reactors are coupled to a Brayton power conversion system allowing each

  7. Stability of large DC power systems using switching converters, with application to the international space station (United States)

    Manners, B.; Gholdston, E. W.; Karimi, K.; Lee, F. C.; Rajagopalan, J.; Panov, Y.


    As space direct current (dc) power systems continue to grow in size, switching power converters are playing an ever larger role in power conditioning and control. When designing a large dc system using power converters of this type, special attention must be placed on the electrical stability of the system and of the individual loads on the system. In the design of the electric power system (EPS) of the International Space Station (ISS), the National Aeronautics and Space Administration (NASA) and its contractor team led by Boeing Defense & Space Group has placed a great deal of emphasis on designing for system and load stability. To achieve this goal, the team has expended considerable effort deriving a dear concept on defining system stability in both a general sense and specifically with respect to the space station. The ISS power system presents numerous challenges with respect to system stability, such as high power, complex sources and undefined loads. To complicate these issues, source and load components have been designed in parallel by three major subcontractors (Boeing, Rocketdyne, and McDonnell Douglas) with interfaces to both sources and loads being designed in different countries (Russia, Japan, Canada, Europe, etc.). These issues, coupled with the program goal of limiting costs, have proven a significant challenge to the program. As a result, the program has derived an impedance specification approach for system stability. This approach is based on the significant relationship between source and load impedances and the effect of this relationship on system stability. This approach is limited in its applicability by the theoretical and practical limits on component designs as presented by each system segment. As a result, the overall approach to system stability implemented by the ISS program consists of specific hardware requirements coupled with extensive system analysis and hardware testing. Following this approach, the ISS program plans to begin

  8. Energetic Argument for Bimodal Black Hole Accretion discs

    Institute of Scientific and Technical Information of China (English)

    林一清; 卢炬甫; 顾为民


    Based on simple energetic considerations, we show that two crucial ingredients of bimodal black hole accretiondiscs, namely the sonic point and the transition radius, can be determined from the disc constant parameters.Thus, we can further justify the model of bimodal discs containing thermal instability triggered transition.

  9. Space Nuclear Power and Propulsion: Materials Challenges for the 21st Century (United States)

    Houts, Mike


    The current focus of NASA s space fission effort is Fission Surface Power (FSP). FSP systems could be used to provide power anytime, anywhere on the surface of the Moon or Mars. FSP systems could be used at locations away from the lunar poles or in permanently shaded regions, with no performance penalty. A potential reference 40 kWe option has been devised that is cost-competitive with alternatives while providing more power for less mass. The potential reference system is readily extensible for use on Mars. At Mars the system could be capable of operating through global dust storms and providing year-round power at any Martian latitude. To ensure affordability, the potential near-term, 40 kWe reference concept is designed to use only well established materials and fuels. However, if various materials challenges could be overcome, extremely high performance fission systems could be devised. These include high power, low mass fission surface power systems; in-space systems with high specific power; and high performance nuclear thermal propulsion systems. This tutorial will provide a brief overview of space fission systems and will focus on materials challenges that, if overcome, could help enable advanced exploration and utilization of the solar system.

  10. Directions in US Air Force space power energy generation and distribution technology (United States)

    Reinhardt, Kitt; Keener, Dave; Schuller, Mike


    Recent trends in the development of high efficiency, light-weight, reliable and cost-effective space power technologies needed to support the development of near-term, next-generation government and commercial satellites will be discussed. Significant advancements in light-weight and reduced volume electrical power system (EPS) components are required to enable the design of future smallsats with power requirements of less than 1000 W to monster-sats having projected power demands ranging from 10-50 kW for civilian and military communications and space based radar needs. For these missions increased emphasis is placed on reducing total satellite mass to enable use of smaller, less costly, and easier to deploy launch vehicles. In support of these requirements a complement of power generation, power management and distribution, and energy storage technologies are under development at the Air Force Phillips Laboratory Space and Missiles Technology Directorate. Specific technologies presented in this paper include high efficiency multijunction solar cells, low-cost thin-film solar cells, ultra light-weight flexible solar arrays, solar electric thermal converters, and high-voltage (70-130 V) and high-efficiency power management and distribution (PMAD) electronics. The projected impact of EPS subsystem performance on existing, near-term, and next-generation 10-50 kW military satellites will be discussed, along with technical issues and status of EPS component development.

  11. Directions in US Air Force space power technology for global virtual presence (United States)

    Keener, David; Reinhardt, Kitt; Mayberry, Clay; Radzykewycz, Dan; Donet, Chuck; Marvin, Dean; Hill, Carole


    Recent trends in the development of high efficiency, light-weight, compact, reliable and cost-effective space power technologies needed to support the development of next-generation military and commercial satellites will be discussed. Development of new light-weight and reduced volume electrical power system (EPS) technologies are required to enable the design of future ``smallsats'' with power requirements less than 1500W, to ``monstersats'' having projected power levels ranging from 10-50kW for commercial communication and military space based radar type satellites. In support of these projected requirements a complement of power generation, power management and distribution, and energy storage technologies are under development at the Air Force Research Laboratory's Space Vehicles Directorate. The technologies presented in this paper include high efficiency multijunction solar cells, alkali metal thermal electric converters (AMTEC), high-voltage (70-130V)/high-efficiency/high-density power management and distribution (PMAD) electronics, and high energy density electrochemical and mechanical energy storage systems (sodium sulfur, lithium-ion, and flywheels). Development issues and impacts of individual technologies will be discussed in context with global presence satellite mission requirements.

  12. Using MapReduce to Improve the Power Generation of the International Space Station (United States)

    Marchetto, William R., II

    The International Space Station (ISS) spends approximately 98% of its time in orbits that experience Earth eclipse. Since the station's solar arrays produce no power when in Earth's shadow, the total power generated decreases substantially, lowering the power budget available to experimental payloads. Therefore, increasing the power output during these eclipsed orbits would be of great benefit to the space station's scientific endeavors. The ISS's current solar array configuration tracks the Sun throughout each orbit, keeping each of its 16 solar panels perpendicular to the Sun at all times. While this is the optimal orientation for solar panels with unobstructed views of the Sun, the space station's solar arrays experience shadowing from the spacecraft's structure as well as from the other solar panels. Deviating from the Sun-tracking scheme at strategic points in certain orbits can provide an increase in power output. The goal of this research was to provide a programmatic solution that increases the power generation capabilities of the ISS in orbits experiencing Earth-eclipse without requiring any physical modifications to the space station's structure. To achieve this goal, a simulator was developed to model the ISS-Earth-Sun environment and calculate the power output of the station's solar arrays based on each panel's orientation and shadowing. Many combinations of array configurations were analyzed, taking into account the physical constraints of the gimbals responsible for rotating the solar panels. The power output of the ISS was improved for the subset of Earth-eclipsed orbits that experience a high degree of shadowing from the station's structure, resulting in an average energy increase of 1.08 kWh per orbit. The power gains were achieved by quickly rotating the solar arrays through the points in each orbit that experienced the highest degree of shadowing.

  13. Bimodal stimulation: benefits for music perception and sound quality. (United States)

    Sucher, Catherine M; McDermott, Hugh J


    With recent expansions in cochlear implantation candidacy criteria, increasing numbers of implantees can exploit their remaining hearing by using bimodal stimulation (combining electrical stimulation via the implant with acoustic stimulation via hearing aids). This study examined the effect of bimodal stimulation on music perception and perceived sound quality. The perception of music and sound quality by nine post-lingually deafened adult implantees was examined in three conditions: implant alone, hearing aid alone and bimodal stimulation. On average, bimodal stimulation provided the best results for music perception and perceived sound quality when compared with results obtained with electrical stimulation alone. Thus, for implantees with usable acoustic hearing, bimodal stimulation may be advantageous when listening to music and other non-speech sounds.

  14. Optimization of phase contrast in bimodal amplitude modulation AFM

    Directory of Open Access Journals (Sweden)

    Mehrnoosh Damircheli


    Full Text Available Bimodal force microscopy has expanded the capabilities of atomic force microscopy (AFM by providing high spatial resolution images, compositional contrast and quantitative mapping of material properties without compromising the data acquisition speed. In the first bimodal AFM configuration, an amplitude feedback loop keeps constant the amplitude of the first mode while the observables of the second mode have not feedback restrictions (bimodal AM. Here we study the conditions to enhance the compositional contrast in bimodal AM while imaging heterogeneous materials. The contrast has a maximum by decreasing the amplitude of the second mode. We demonstrate that the roles of the excited modes are asymmetric. The operational range of bimodal AM is maximized when the second mode is free to follow changes in the force. We also study the contrast in trimodal AFM by analyzing the kinetic energy ratios. The phase contrast improves by decreasing the energy of second mode relative to those of the first and third modes.

  15. Optimization of phase contrast in bimodal amplitude modulation AFM. (United States)

    Damircheli, Mehrnoosh; Payam, Amir F; Garcia, Ricardo


    Bimodal force microscopy has expanded the capabilities of atomic force microscopy (AFM) by providing high spatial resolution images, compositional contrast and quantitative mapping of material properties without compromising the data acquisition speed. In the first bimodal AFM configuration, an amplitude feedback loop keeps constant the amplitude of the first mode while the observables of the second mode have not feedback restrictions (bimodal AM). Here we study the conditions to enhance the compositional contrast in bimodal AM while imaging heterogeneous materials. The contrast has a maximum by decreasing the amplitude of the second mode. We demonstrate that the roles of the excited modes are asymmetric. The operational range of bimodal AM is maximized when the second mode is free to follow changes in the force. We also study the contrast in trimodal AFM by analyzing the kinetic energy ratios. The phase contrast improves by decreasing the energy of second mode relative to those of the first and third modes.

  16. Efficient coding schemes with power allocation using space-time-frequency spreading

    Institute of Scientific and Technical Information of China (English)

    Jiang Haining; Luo Hanwen; Tian Jifeng; Song Wentao; Liu Xingzhao


    An efficient space-time-frequency (STF) coding strategy for multi-input multi-output orthogonal frequency division multiplexing (MIMO-OFDM) systems is presented for high bit rate data transmission over frequency selective fading channels. The proposed scheme is a new approach to space-time-frequency coded OFDM (COFDM) that combines OFDM with space-time coding, linear precoding and adaptive power allocation to provide higher quality of transmission in terms of the bit error rate performance and power efficiency. In addition to exploiting the maximum diversity gain in frequency, time and space, the proposed scheme enjoys high coding advantages and low-complexity decoding. The significant performance improvement of our design is confirmed by corroborating numerical simulations.

  17. On the Statistics of Noisy Space Vector in Power Quality Analysis

    Directory of Open Access Journals (Sweden)

    Diego Bellan


    Full Text Available This work deals with the analysis of the impact of additive noise on the geometrical features of the space vector shape on the complex plane. The space vector shape is of great importance in the power quality analysis of modern three-phase power systems since its geometrical features are closely related to the voltage supply quality. In case of voltage sag or swell the space vector shape changes accordingly. In case of additive noise the geometrical parameters of the space vector shape can be treated as random variables. In the paper, the mean values and the variances of such parameters are derived in closed form as functions of the noise level and of the sampling conditions. Analytical results are validated through numerical simulation of the whole measurement process.

  18. Emergence of bimodality in controlling complex networks

    CERN Document Server

    Jia, Tao; Csóka, Endre; Pósfai, Márton; Slotine, Jean-Jacques; Barabási, Albert-László


    Our ability to control complex systems is a fundamental challenge of contemporary science. Recently introduced tools to identify the driver nodes, nodes through which we can achieve full control, predict the existence of multiple control configurations, prompting us to classify each node in a network based on their role in control. Accordingly a node is critical, intermittent or redundant if it acts as a driver node in all, some or none of the control configurations. Here we develop an analytical framework to identify the category of each node, leading to the discovery of two distinct control modes in complex systems: centralized vs distributed control. We predict the control mode for an arbitrary network and show that one can alter it through small structural perturbations. The uncovered bimodality has implications from network security to organizational research and offers new insights into the dynamics and control of complex systems.

  19. A Closed Brayton Power Conversion Unit Concept for Nuclear Electric Propulsion for Deep Space Missions (United States)

    Joyner, Claude Russell; Fowler, Bruce; Matthews, John


    In space, whether in a stable satellite orbit around a planetary body or traveling as a deep space exploration craft, power is just as important as the propulsion. The need for power is especially important for in-space vehicles that use Electric Propulsion. Using nuclear power with electric propulsion has the potential to provide increased payload fractions and reduced mission times to the outer planets. One of the critical engineering and design aspects of nuclear electric propulsion at required mission optimized power levels is the mechanism that is used to convert the thermal energy of the reactor to electrical power. The use of closed Brayton cycles has been studied over the past 30 or years and shown to be the optimum approach for power requirements that range from ten to hundreds of kilowatts of power. It also has been found to be scalable to higher power levels. The Closed Brayton Cycle (CBC) engine power conversion unit (PCU) is the most flexible for a wide range of power conversion needs and uses state-of-the-art, demonstrated engineering approaches. It also is in use with many commercial power plants today. The long life requirements and need for uninterrupted operation for nuclear electric propulsion demands high reliability from a CBC engine. A CBC engine design for use with a Nuclear Electric Propulsion (NEP) system has been defined based on Pratt & Whitney's data from designing long-life turbo-machines such as the Space Shuttle turbopumps and military gas turbines and the use of proven integrated control/health management systems (EHMS). An integrated CBC and EHMS design that is focused on using low-risk and proven technologies will over come many of the life-related design issues. This paper will discuss the use of a CBC engine as the power conversion unit coupled to a gas-cooled nuclear reactor and the design trends relative to its use for powering electric thrusters in the 25 kWe to 100kWe power level.

  20. Analysis of electromagnetic interference from power system processing and transmission components for Space Station Freedom (United States)

    Barber, Peter W.; Demerdash, Nabeel A. O.; Hurysz, B.; Luo, Z.; Denny, Hugh W.; Millard, David P.; Herkert, R.; Wang, R.


    The goal of this research project was to analyze the potential effects of electromagnetic interference (EMI) originating from power system processing and transmission components for Space Station Freedom. The approach consists of four steps: (1) developing analytical tools (models and computer programs); (2) conducting parameterization (what if?) studies; (3) predicting the global space station EMI environment; and (4) providing a basis for modification of EMI standards.

  1. Parametric analysis of hollow conductor parallel and coaxial transmission lines for high frequency space power distribution (United States)

    Jeffries, K. S.; Renz, D. D.


    A parametric analysis was performed of transmission cables for transmitting electrical power at high voltage (up to 1000 V) and high frequency (10 to 30 kHz) for high power (100 kW or more) space missions. Large diameter (5 to 30 mm) hollow conductors were considered in closely spaced coaxial configurations and in parallel lines. Formulas were derived to calculate inductance and resistance for these conductors. Curves of cable conductance, mass, inductance, capacitance, resistance, power loss, and temperature were plotted for various conductor diameters, conductor thickness, and alternating current frequencies. An example 5 mm diameter coaxial cable with 0.5 mm conductor thickness was calculated to transmit 100 kW at 1000 Vac, 50 m with a power loss of 1900 W, an inductance of 1.45 micron and a capacitance of 0.07 micron-F. The computer programs written for this analysis are listed in the appendix.

  2. Short-term wind power forecasting: probabilistic and space-time aspects

    DEFF Research Database (Denmark)

    Tastu, Julija

    point to probabilistic forecasts is dealt with, hence requiring to describe the uncertainty associated with the point predictions previously generated. Both parametric and non-parametric approaches to forming predictive densities are considered, while ways to include space-time effects......Optimal integration of wind energy into power systems calls for high quality wind power predictions. State-of-the-art forecasting systems typically provide forecasts for every location individually, without taking into account information coming from the neighbouring territories. It is however...... work deals with the proposal and evaluation of new mathematical models and forecasting methods for short-term wind power forecasting, accounting for space-time dynamics based on geographically distributed information. Different forms of power predictions are considered, starting from traditional point...

  3. Space Nuclear Power Plant Pre-Conceptual Design Report, For Information

    Energy Technology Data Exchange (ETDEWEB)

    B. Levine


    This letter transmits, for information, the Project Prometheus Space Nuclear Power Plant (SNPP) Pre-Conceptual Design Report completed by the Naval Reactors Prime Contractor Team (NRPCT). This report documents the work pertaining to the Reactor Module, which includes integration of the space nuclear reactor with the reactor radiation shield, energy conversion, and instrumentation and control segments. This document also describes integration of the Reactor Module with the Heat Rejection segment, the Power Conditioning and Distribution subsystem (which comprise the SNPP), and the remainder of the Prometheus spaceship.

  4. Note on Power-Law Inflation in Noncommutative Space-Time

    CERN Document Server

    Feng, Chao-Jun; Liu, Dao-Jun


    In this paper, we propose a new method to calculate the mode functions in the noncommutative power-law inflation model. In this model, all the modes created when the stringy space-time uncertainty relation is satisfied are generated inside the Hubble horizon during inflation. It turns out that a linear term describing the noncommutative space-time effect contributes to the power spectra of the scalar and tensor perturbations. Confronting this model with latest results from \\textit{Planck} and BICEP2, we constrain the parameters in this model and we find it is well consistent with observations.

  5. Advanced Magnetic-Nuclear Power Systems for Reliability Demanding Applications Including Deep Space Missions



    The MAGNUS concept, which is based on the FFMCR approach, offers space power and propulsion technology with a number of unique characteristics such as: ï‚· Direct FF energy conversion is uniquely suitable for space operation; ï‚· High efficiency DEC promises reduced thermal control and radiators; ï‚· High specific impulse allows short trip times and extends exploration to the outer reaches of the solar system and beyond; ï‚· Achievability of long-term operation assures power for missions with...

  6. Overview of high-temperature materials for high-energy space power systems (United States)

    Saunders, N. T.


    The current state of technology and some of the more pressing research needs and challenges associated with the possible use of high temperature materials in future high energy space power systems are discussed. Particularly, emphasis is on the need to improve and quantify the fundamental understanding of the effects of the following: (1) fast neutron radiation on the properties and behavior of nuclear reactor fuels and claddings; and (2) long term, high temperature, space (vacuum) exposure on the properties of refractory metals considered for use as structural materials in various power conversion systems.

  7. Space-time trajectories of wind power generation: Parameterized precision matrices under a Gaussian copula approach

    DEFF Research Database (Denmark)

    Tastu, Julija; Pinson, Pierre; Madsen, Henrik


    Emphasis is placed on generating space-time trajectories of wind power generation, consisting of paths sampled from high-dimensional joint predictive densities, describing wind power generation at a number of contiguous locations and successive lead times. A modelling approach taking advantage......-correlations. Estimation is performed in a maximum likelihood framework. Based on a test case application in Denmark, with spatial dependencies over 15 areas and temporal ones for 43 hourly lead times (hence, for a dimension of n = 645), it is shown that accounting for space-time effects is crucial for generating skilful...

  8. On power flow suppression in straight elastic pipes by use of equally spaced eccentric inertial attachments

    DEFF Research Database (Denmark)

    Sorokin, Sergey; Holst-Jensen, Ole


    of the problem in vibrations of this structure. The power flow analysis in a pipe with and without equally spaced eccentric inertial attachments is performed and the effect of suppression of the energy transmission is demonstrated theoretically. These results are put in the context of predictions from......The paper addresses the power flow suppression in an elastic beam of the tubular cross section (a pipe) at relatively low excitation frequencies by deploying a small number of equally spaced inertial attachments. The methodology of boundary integral equations is used to obtain an exact solution...

  9. Perturbation theory approach for the power spectrum: from dark matter in real space to massive haloes in redshift space

    Energy Technology Data Exchange (ETDEWEB)

    Gil-Marín, Héctor [Institut de Ciències de l' Espai (ICE), Facultat de Ciències, Campus UAB (IEEC-CSIC), Bellaterra E-08193 (Spain); Wagner, Christian; Verde, Licia; Jimenez, Raul [Institut de Ciències del Cosmos (ICC), Universitat de Barcelona (IEEC-UB), Martí i Franquès 1, Barcelona E-08028 (Spain); Porciani, Cristiano, E-mail:, E-mail:, E-mail:, E-mail:, E-mail: [Argelander Institut für Astronomie der Universität Bonn, Auf dem Hügel 71, D-53121 Bonn (Germany)


    We investigate the accuracy of Eulerian perturbation theory for describing the matter and galaxy power spectra in real and redshift space in light of future observational probes for precision cosmology. Comparing the analytical results with a large suite of N-body simulations (160 independent boxes of 13.8 (Gpc/h){sup 3} volume each, which are publicly available), we find that re-summing terms in the standard perturbative approach predicts the real-space matter power spectrum with an accuracy of ∼<2% for k ≤ 0.20 h/Mpc at redshifts z∼<1.5. This is obtained following the widespread technique of writing the resummed propagator in terms of 1-loop contributions. We show that the accuracy of this scheme increases by considering higher-order terms in the resummed propagator. By combining resummed perturbation theories with several models for the mappings from real to redshift space discussed in the literature, the multipoles of the dark-matter power spectrum can be described with sub-percent deviations from N-body results for k ≤ 0.15 h/Mpc at z∼<1. As a consequence, the logarithmic growth rate, f, can be recovered with sub-percent accuracy on these scales. Extending the models to massive dark-matter haloes in redshift space, our results describe the monopole term from N-body data within 2% accuracy for scales k ≤ 0.15 h/Mpc at z∼<0.5; here f can be recovered within < 5% when the halo bias is known. We conclude that these techniques are suitable to extract cosmological information from future galaxy surveys.

  10. The electric rail gun for space propulsion (United States)

    Bauer, D. P.; Barber, J. P.; Vahlberg, C. J.


    An analytic feasibility investigation of an electric propulsion concept for space application is described. In this concept, quasistatic thrust due to inertial reaction to repetitively accelerated pellets by an electric rail gun is used to propel a spacecraft. The study encompasses the major subsystems required in an electric rail gun propulsion system. The mass, performance, and configuration of each subsystem are described. Based on an analytic model of the system mass and performance, the electric rail gun mission performance as a reusable orbital transfer vehicle (OTV) is analyzed and compared to a 30 cm ion thruster system (BIMOD) and a chemical propulsion system (IUS) for payloads with masses of 1150 kg and 2300 kg. For system power levels in the range from 25 kW(e) to 100 kW(e) an electric rail gun OTV is more attractive than a BIMOD system for low Earth orbit to geosynchronous orbit transfer durations in the range from 20 to 120 days.

  11. Space Power Program Semiannual Progress Report for period ending June 30, 1963

    Energy Technology Data Exchange (ETDEWEB)

    Miller, A. J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)


    This is a report of progress on the Oak Ridge National Laboratory's research and development program on nuclear power plants for electrical power production in space vehicles. The work is carried out under AEG Reactor Experiments, Fuels, and Materials, and Reactor Component programs. Research and development work is under way on the stainless steel boiling-potassium reactor and the Medium Power Reactor Experiment, boiling alkali metal heat transfer, high-temperature and refractory alloys, fuel material, and space reactor shielding, particularly in connection with SNAP 2, 8, 10, and 50. Many of these OREL efforts are directed toward the development of a specific type of power plant, but they also furnish a significant contribution of scientific and engineering information needed in other programs on advanced SNAP systems. Progress on research and development directly related to the Medium Power Reactor Experiment (MPRE) is presented mostly in Part I of this report. Progress on the MPRE will, in the future, be reported on a quarterly basis. The form of the reporting will alternate from MPRE Quarterly Progress Reports to Space Power Semiannual Progress Reports.

  12. Space debris proximity analysis in powered and orbital phases during satellite launch (United States)

    Bandyopadhyay, Priyankar; Sharma, R. K.; Adimurthy, V.


    This paper describes the methodology of the space debris proximity analysis in powered and orbital phase at the time of a satellite launch. The details of the SPADEPRO analysis package, developed for this purpose, are presented. It consists of modules which provide the functions related to ephemeris generation and reconstruction of primary object (launch vehicle or its payload upon insertion), determination of close approaches with resident space objects, computation of the state vector variance of the primary and the secondary objects to represent the knowledge uncertainty, and computation of the collision risk given the variance. This has been successfully applied during the recent launches of the Indian Space Research Organization.

  13. Radiation resistance of thin-film solar cells for space photovoltaic power (United States)

    Woodyard, James R.; Landis, Geoffrey A.


    Copper indium diselenide, cadmium telluride, and amorphous silicon alloy solar cells have achieved noteworthy performance and are currently being studied for space power applications. Cadmium sulfide cells had been the subject of much effort but are no longer considered for space applications. A review is presented of what is known about the radiation degradation of thin film solar cells in space. Experimental cadmium telluride and amorphous silicon alloy cells are reviewed. Damage mechanisms and radiation induced defect generation and passivation in the amorphous silicon alloy cell are discussed in detail due to the greater amount of experimental data available.

  14. Small space reactor power systems for unmanned solar system exploration missions

    Energy Technology Data Exchange (ETDEWEB)

    Bloomfield, H.S.


    A preliminary feasibility study of the application of small nuclear reactor space power systems to the Mariner Mark II Cassini spacecraft/mission was conducted. The purpose of the study was to identify and assess the technology and performance issues associated with the reactor power system/spacecraft/mission integration. The Cassini mission was selected because study of the Saturn system was identified as a high priority outer planet exploration objective. Reactor power systems applied to this mission were evaluated for two different uses. First, a very small 1 kWe reactor power system was used as an RTG replacement for the nominal spacecraft mission science payload power requirements while still retaining the spacecraft's usual bipropellant chemical propulsion system. The second use of reactor power involved the additional replacement of the chemical propulsion system with a small reactor power system and an electric propulsion system. The study also provides an examination of potential applications for the additional power available for scientific data collection. The reactor power system characteristics utilized in the study were based on a parametric mass model that was developed specifically for these low power applications. The model was generated following a neutronic safety and operational feasibility assessment of six small reactor concepts solicited from U.S. industry. This assessment provided the validation of reactor safety for all mission phases and generatad the reactor mass and dimensional data needed for the system mass model.

  15. Passive Shielding Effect on Space Profile of Magnetic Field Emissions for Wireless Power Transfer to Vehicles

    DEFF Research Database (Denmark)

    Batra, Tushar; Schaltz, Erik


    Magnetic fields emitted by wireless power transfer systems are of high importance with respect to human safety and health. Aluminum and ferrite are used in the system to reduce the fields and are termed as passive shielding. In this paper, the influence of these materials on the space profile has...... fields for wireless power transfer for vehicle applications....... been investigated with the help of simulations on Comsol for the four possible geometries—no shielding, ferrite, aluminum, and full shielding. As the reflected impedance varies for the four geometries, the primary current is varied accordingly to maintain constant power transfer to the secondary side...

  16. Optical sensing in high voltage transmission lines using power over fiber and free space optics (United States)

    Rosolem, João Batista; Bassan, Fabio Renato; Penze, Rivael Strobel; Leonardi, Ariovaldo Antonio; Fracarolli, João Paulo Vicentini; Floridia, Claudio


    In this work we propose the use of power over fiber (PoF) and free space optics (FSO) techniques to powering and receive signals from an electrical current sensor placed at high voltage potential using a pair of optical collimators. The technique evaluation was performed in a laboratorial prototype using 62.5/125 μm multimode fiber to study the sensitivity of the optical alignment and the influence of the collimation process in the sensing system wavelengths: data communication (1310 nm) and powering (830 nm). The collimators were installed in a rigid electric insulator in order to maintain the stability of transmission.


    National Aeronautics and Space Administration — Solar cells are the critical power source for the majority of space missions. The advancement from single junction silicon cells to current, state-of-the-art, triple...

  18. Historical perspectives: The role of the NASA Lewis Research Center in the national space nuclear power programs (United States)

    Bloomfield, H. S.; Sovie, R. J.


    The history of the NASA Lewis Research Center's role in space nuclear power programs is reviewed. Lewis has provided leadership in research, development, and the advancement of space power and propulsion systems. Lewis' pioneering efforts in nuclear reactor technology, shielding, high temperature materials, fluid dynamics, heat transfer, mechanical and direct energy conversion, high-energy propellants, electric propulsion and high performance rocket fuels and nozzles have led to significant technical and management roles in many national space nuclear power and propulsion programs.

  19. More Wind Power Integration with Adjusted Energy Carriers for Space Heating in Northern China

    Directory of Open Access Journals (Sweden)

    Jianjun He


    Full Text Available In Northern China, due to the high penetration of coal-fired cogeneration facilities, which are generally equipped with extraction-condensing steam turbines, lots of wind power resources may be wasted during the heating season. In contrast, considerable coal is consumed in the power generation sector. In this article, firstly it is revealed that there exists a serious divergence in the ratio of electrical to thermal energy between end users’ demand and the cogenerations’ production during off-peak load at night, which may negate active power-balancing of the electric power grid. Secondly, with respect to this divergence only occurring during off-peak load at night, a temporary proposal is given so as to enable the integration of more wind power. The authors suggest that if the energy carrier for part of the end users’ space heating is switched from heating water to electricity (e.g., electric heat pumps (EHPs can provide space heating in the domestic sector, the ratio of electricity to heating water load should be adjusted to optimize the power dispatch between cogeneration units and wind turbines, resulting in fuel conservation. With this proposal, existing infrastructures are made full use of, and no additional ones are required. Finally a numerical simulation is performed in order to illustrate both the technical and economic feasibility of the aforementioned proposal, under ongoing infrastructures as well as electricity and space heating tariff conditions without changing participants’ benefits. The authors aim to persuade Chinese policy makers to enable EHPs to provide space heating to enable the integration of more wind power.

  20. High Efficiency Space Power Systems Project Advanced Space-Rated Batteries (United States)

    Reid, Concha M.


    Case Western Reserve University (CWRU) has an agreement with China National Offshore Oil Corporation New Energy Investment Company, Ltd. (CNOOC), under the United States-China EcoPartnerships Framework, to create a bi-national entity seeking to develop technically feasible and economically viable solutions to energy and environmental issues. Advanced batteries have been identified as one of the initial areas targeted for collaborations. CWRU invited NASA Glenn Research Center (GRC) personnel from the Electrochemistry Branch to CWRU to discuss various aspects of advanced battery development as they might apply to this partnership. Topics discussed included: the process for the selection of a battery chemistry; the establishment of an integrated development program; project management/technical interactions; new technology developments; and synergies between batteries for automotive and space operations. Additional collaborations between CWRU and NASA GRC's Electrochemistry Branch were also discussed.

  1. Micro space power system using MEMS fuel cell for nano-satellites (United States)

    Lee, Jongkwang; Kim, Taegyu


    A micro space power system using micro fuel cell was developed for nano-satellites. The power system was fabricated using microelectromechanical system (MEMS) fabrication technologies. Polymer electrolyte membrane (PEM) fuel cell was selected in consideration of space environment. Sodium borohydride (NaBH4) was selected as a hydrogen source while hydrogen peroxide (H2O2) was selected as an oxygen source. The power system consists of a micro fuel cell, micro-reactor, micro-pump, and fuel cartridges. The micro fuel cell was fabricated on a light-weight and corrosion-resistant glass plates. The micro-reactor was used to generate hydrogen from NaBH4 alkaline solution via a catalytic hydrolysis reaction. All components such as micro-pump, fuel cartridges, and auxiliary battery were integrated for a complete power system. The storability of NaBH4 solution was evaluated at -25 °C and the performance of the micro power system was measured at various operating conditions. The power output of micro power system reasonably followed up the given electric load conditions.

  2. High Intensity Laser Power Beaming Architecture for Space and Terrestrial Missions (United States)

    Nayfeh, Taysir; Fast, Brian; Raible, Daniel; Dinca, Dragos; Tollis, Nick; Jalics, Andrew


    High Intensity Laser Power Beaming (HILPB) has been developed as a technique to achieve Wireless Power Transmission (WPT) for both space and terrestrial applications. In this paper, the system architecture and hardware results for a terrestrial application of HILPB are presented. These results demonstrate continuous conversion of high intensity optical energy at near-IR wavelengths directly to electrical energy at output power levels as high as 6.24 W from the single cell 0.8 cm2 aperture receiver. These results are scalable, and may be realized by implementing receiver arraying and utilizing higher power source lasers. This type of system would enable long range optical refueling of electric platforms, such as MUAV s, airships, robotic exploration missions and provide power to spacecraft platforms which may utilize it to drive electric means of propulsion.

  3. Directly solar-pumped iodine laser for beamed power transmission in space (United States)

    Choi, S. H.; Meador, W. E.; Lee, J. H.


    A new approach for development of a 50-kW directly solar-pumped iodine laser (DSPIL) system as a space-based power station was made using a confocal unstable resonator (CUR). The CUR-based DSPIL has advantages, such as performance enhancement, reduction of total mass, and simplicity which alleviates the complexities inherent in the previous system, master oscillator/power amplifier (MOPA) configurations. In this design, a single CUR-based DSPIL with 50-kW output power was defined and compared to the MOPA-based DSPIL. Integration of multiple modules for power requirements more than 50-kW is physically and structurally a sound approach as compared to building a single large system. An integrated system of multiple modules can respond to various mission power requirements by combining and aiming the coherent beams at the user's receiver.

  4. Roles of factorial noise in inducing bimodal gene expression (United States)

    Liu, Peijiang; Yuan, Zhanjiang; Huang, Lifang; Zhou, Tianshou


    Some gene regulatory systems can exhibit bimodal distributions of mRNA or protein although the deterministic counterparts are monostable. This noise-induced bimodality is an interesting phenomenon and has important biological implications, but it is unclear how different sources of expression noise (each source creates so-called factorial noise that is defined as a component of the total noise) contribute separately to this stochastic bimodality. Here we consider a minimal model of gene regulation, which is monostable in the deterministic case. Although simple, this system contains factorial noise of two main kinds: promoter noise due to switching between gene states and transcriptional (or translational) noise due to synthesis and degradation of mRNA (or protein). To better trace the roles of factorial noise in inducing bimodality, we also analyze two limit models, continuous and adiabatic approximations, apart from the exact model. We show that in the case of slow gene switching, the continuous model where only promoter noise is considered can exhibit bimodality; in the case of fast switching, the adiabatic model where only transcriptional or translational noise is considered can also exhibit bimodality but the exact model cannot; and in other cases, both promoter noise and transcriptional or translational noise can cooperatively induce bimodality. Since slow gene switching and large protein copy numbers are characteristics of eukaryotic cells, whereas fast gene switching and small protein copy numbers are characteristics of prokaryotic cells, we infer that eukaryotic stochastic bimodality is induced mainly by promoter noise, whereas prokaryotic stochastic bimodality is induced primarily by transcriptional or translational noise.

  5. Thermal stability improvement of a multiple finger power SiGe heterojunction bipolar transistor under different power dissipations using non-uniform finger spacing

    Institute of Scientific and Technical Information of China (English)

    Chen Liang; Zhang Wan-Rong; Jin Dong-Yue; Shen Pei; Xie Hong-Yun; Ding Chun-Bao; Xiaa Ying; Sun Bo-Tao; Wang Ren-Qing


    method of non-uniform finger spacing is proposed to enhance thermal stability of a multiple finger power SiGe hererojunction bipolar transistor under different power dissipations. Temperature distribution on the emitter fingers of a multi-finger SiGe heterojunction bipolar transistor is studied using a numerical electro-thermal model. The results show that the SiGe heterojunction bipolar transistor with non-uniform finger spacing has a small temperature difference between fingers compared with a traditional uniform finger spacing heterojunction bipolar transistor at the same power dissipation. What is most important is that the ability to improve temperature non-uniformity is not weakened as power dissipation increases. So the method of non-uniform finger spacing is very effective in enhancing the thermal stability and the power handing capability of power device. Experimental results verify our conclusious.

  6. Evaluation of Power Electronic Components and Systems at Cryogenic Temperatures For Space Missions (United States)

    Elbuluk, Malik E.; Gerber, Scott; Hammoud, Ahmad; Patterson, Richard L.


    Power electronic circuits and systems designed for deep space applications and outer planetary exploration are required to operate reliably and efficiently under extreme temperature conditions. This requirement is dictated by the fact that the operational environments associated with some of the space missions would encompass temperatures as low as -183 C. The development and utilization of electronics capable of low temperature operation would not only fulfill the advanced technology requirements, but also would contribute to improving circuit performance, increasing system efficiency, and reducing development and launch costs. These benefits are generally achieved by the improved intrinsic properties of some of the electronic materials at low temperature, reduced device losses, and the elimination of heating elements used in conventional systems at low temperatures. Power electronic circuits are widely used in space power systems in the areas of power management, conditioning, and control. In this work, the performance of certain power electronic components and systems was investigated under low temperature. These include inductors, capacitors, pulse-width-modulation (PWM) controllers, and advanced commercial DC/DC converter modules. Different properties were determined as a function of temperature in the range of 20 C to -140 C, at various current and voltages levels. The experimental procedures along with the experimental data obtained are presented and discussed in this paper.

  7. Definition and economic evaluation of Space Solar Power Systems (SSPS), part 1 (United States)

    Koelle, H. H.; Sputek, K.; Schulze, M.


    A life cycle model of a typical space power system (SPS) in the first half of the next century is described. Inputs for this logistics model are: life cycle duration (100 yr); power level of the SPS at the end of life cycle assumed (500 GW); power level for single SPS unit (5 GW); availability of space power units (90 %); and specific mass (Mg/MW) of SPS as a function of time. A system of 100 operating space power units in geostationary orbit with an output of 500 GW in its 50th year requires in this year a total mass flow of 200,000 T. To operate the system, a crew size in GEO is 600 people. The total mass installed in the SPS is 6 million metric tons. To transport this material to the GEO from Earth and from the Moon, average annual launch rates of 300 for the lunar bus and 340 for the heavy lift launch vehicle during the 50 yr time period are required. The average annual output of the SPS is economically attractive: 2188 TWh at 7.4 mills/kWh.

  8. Baryon Acoustic Oscillations in 2D: Modeling Redshift-space Power Spectrum from Perturbation Theory

    CERN Document Server

    Taruya, Atsushi; Saito, Shun


    We present an improved prescription for matter power spectrum in redshift space taking a proper account of both the non-linear gravitational clustering and redshift distortion, which are of particular importance for accurately modeling baryon acoustic oscillations (BAOs). Contrary to the models of redshift distortion phenomenologically introduced but frequently used in the literature, the new model includes the corrections arising from the non-linear coupling between the density and velocity fields associated with two competitive effects of redshift distortion, i.e., Kaiser and Finger-of-God effects. Based on the improved treatment of perturbation theory for gravitational clustering, we compare our model predictions with monopole and quadrupole power spectra of N-body simulations, and an excellent agreement is achieved over the scales of BAOs. Potential impacts on constraining dark energy and modified gravity from the redshift-space power spectrum are also investigated based on the Fisher-matrix formalism. We...

  9. Modeling and Simulation of DC Power Electronics Systems Using Harmonic State Space (HSS) Method

    DEFF Research Database (Denmark)

    Kwon, Jun Bum; Wang, Xiongfei; Bak, Claus Leth


    For the efficiency and simplicity of electric systems, the dc based power electronics systems are widely used in variety applications such as electric vehicles, ships, aircrafts and also in homes. In these systems, there could be a number of dynamic interactions between loads and other dc...... based on the state-space averaging and generalized averaging, these also have limitations to show the same results as with the non-linear time domain simulations. This paper presents a modeling and simulation method for a large dc power electronic system by using Harmonic State Space (HSS) modeling....... Through this method, the required computation time and CPU memory for large dc power electronics systems can be reduced. Besides, the achieved results show the same results as with the non-linear time domain simulation, but with the faster simulation time which is beneficial in a large network....

  10. Comments on dual-mode nuclear space power and propulsion system concepts (United States)

    Layton, J. Preston; Grey, Jerry


    Some form of Dual-Mode Nuclear Space Power & Propulsion System (D-MNSP&PS) will be essential to spacefaring throughout teh solar system and that such systems must evolve as mankind moves into outer space. The initial D-MNPSP&PS Reference System should be based on (1) present (1990), and (2) advanced (1995) technology for use on comparable mission in the 2000 and 2005 time period respectively. D-MNSP&PS can be broken down into a number of subsystems: Nuclear subsystems including the energy source and controls for the release of thermal power at elevated temperatures; power conversion subsystems; waste heat rejection subsystems; and control and safety subsystems. These systems are briefly detailed.

  11. Vehicle and Mission Design Options for the Human Exploration of Mars/Phobos Using "Bimodal" NTR and LANTR Propulsion (United States)

    Borowski, Stanley K.; Dudzinski, Leonard A.; McGuire, Melissa L.


    The nuclear thermal rocket (NTR) is one of the leading propulsion options for future human missions to Mars because of its high specific impulse (1sp is approximately 850-1000 s) capability and its attractive engine thrust-to-weight ratio (approximately 3-10). To stay within the available mass and payload volume limits of a "Magnum" heavy lift vehicle, a high performance propulsion system is required for trans-Mars injection (TMI). An expendable TMI stage, powered by three 15 thousand pounds force (klbf) NTR engines is currently under consideration by NASA for its Design Reference Mission (DRM). However, because of the miniscule burnup of enriched uranium-235 during the Earth departure phase (approximately 10 grams out of 33 kilograms in each NTR core), disposal of the TMI stage and its engines after a single use is a costly and inefficient use of this high performance stage. By reconfiguring the engines for both propulsive thrust and modest power generation (referred to as "bimodal" operation), a robust, multiple burn, "power-rich" stage with propulsive Mars capture and reuse capability is possible. A family of modular bimodal NTR (BNTR) vehicles are described which utilize a common "core" stage powered by three 15 klbf BNTRs that produce 50 kWe of total electrical power for crew life support, an active refrigeration / reliquification system for long term, zero-boiloff liquid hydrogen (LH2) storage, and high data rate communications. An innovative, spine-like "saddle truss" design connects the core stage and payload element and is open underneath to allow supplemental "in-line" propellant tanks and contingency crew consumables to be easily jettisoned to improve vehicle performance. A "modified" DRM using BNTR transfer vehicles requires fewer transportation system elements, reduces IMLEO and mission risk, and simplifies space operations. By taking the next logical step--use of the BNTR for propulsive capture of all payload elements into Mars orbit--the power

  12. Development of a Novel Wireless Electric Power Transfer System for Space Applications (United States)

    VazquezRamos, Gabriel; Yuan, Jiann-Shiun


    This paper will introduce a new implementation for wireless electric power transfer systems: space applications. Due to the risks that constitute the use of electrical connector for some space missions/applications, a simple wireless power system design approach will be evaluated as an alternative for the use of electrical connectors. This approach takes into consideration the overall system performance by designing the magnetic resonance elements and by verifying the overall system electrical behavior. System characterization is accomplished by executing circuit and analytical simulations using Matlab(TradeMark) and LTSpiceIV(TradeMark) software packages. The design methodology was validated by two different experiments: frequency consideration (design of three magnetic elements) and a small scale proof-ofconcept prototype. Experiment results shows successful wireless power transfer for all the cases studied. The proof-of-concept prototype provided approx.4 W of wireless power to the load (light bulb) at a separation of 3 cm from the source. In addition. a resonant circuit was designed and installed to the battery terminals of a handheld radio without batteries, making it tum on at a separation of approx.5 cm or less from the source. It was also demonstrated by prototype experimentation that multiple loads can be powered wirelessly at the same time with a single electric power source.

  13. Reference concepts for a space-based hydrogen-oxygen combustion, turboalternator, burst power system

    Energy Technology Data Exchange (ETDEWEB)

    Edenburn, M.W.


    This report describes reference concepts for a hydrogen-oxygen combustion, turboalternator power system that supplies power during battle engagement to a space-based, ballistic missile defense platform. All of the concepts are open''; that is, they exhaust hydrogen or a mixture of hydrogen and water vapor into space. We considered the situation where hydrogen is presumed to be free to the power system because it is also needed to cool the platform's weapon and the situation where hydrogen is not free and its mass must be added to that of the power system. We also considered the situation where water vapor is an acceptable exhaust and the situation where it is not. The combination of these two sets of situations required four different power generation systems, and this report describes each, suggests parameter values, and estimates masses for each of the four. These reference concepts are expected to serve as a baseline'' to which other types of power systems can be compared, and they are expected to help guide technology development efforts in that they suggest parameter value ranges that will lead to optimum system designs. 7 refs., 18 figs., 5 tabs.

  14. Reflection on Development of Space Power and Space Security%我国空间力量发展与空间安全的思考

    Institute of Scientific and Technical Information of China (English)



    空间力量作为维护国家空间安全与利益的物质基础和综合国力新的增长源,在国家安全与发展中的地位与作用越来越突出.分析了我国空间力量发展的现状和诸多制约因素,研究了空间安全对维护国家安全的重要作用,提出了制定空间战略、发展空间力量、维护空间安全和提升综合国力的对策思考.%Space power is not only the material foundation of maintaining space security and interest, but also a new source of development of comprehensive national power. And it's playing a more and more prominent role in a country's security and development. The actualities of our country's space power are analyzed, and the restriction of the development of our country's space power is concluded. The vital function which space security plays on safeguarding national security is studied. The eountermeasures about constituting space strategy, developing space power, maintaining space security and advancing comprehensive national power are put forward.

  15. High-Power Amplifier Compatible Internally Sensed Optical Phased Array for Space Debris Tracking and Maneuvering (United States)

    Roberts, L.; Francis, S.; Sibley, P.; Ward, R.; Smith, C.; McClelland, D.; Shaddock, D.


    Optical phased arrays (OPAs) provide a way to scale optical power beyond the capabilities of conventional CW lasers via coherent beam combination. By stabilising the relative output phase of multiple spatially separate lasers, OPAs form a coherent optical wavefront in the far field. Since the phase of each laser can be controlled independently, OPAs also have the ability to manipulate the distribution of optical power in the far field, and therefore may provide the capability to compensate for atmospheric turbulence. Combined with their inherent scalability and high power handling capabilities, OPAs are a promising technology for CW space debris ranging and manoeuvring. The OPA presented here is unique in its ability to sense the phase of each laser internally, without requiring any external sampling optics between it and the telescope. This allows the internally sensed OPA to be constructed entirely within fibre, utilising high-power fiber amplifiers to scale optical power beyond the limits of any conventional single lasers. The total power that can be delivered by each emitter in the OPA is limited only by the onset of stimulated Brillouin scattering, a non-linear effect that clamps the amount of power that can be delivered through a fiber waveguide. A three element internally sensed OPA developed at the Australian National University has been demonstrated to coherently combine three commercial 15 Watt fiber amplifiers with an output phase stability of one 200th of a wavelength. We have also demonstrated the ability to dynamically manipulate the distribution of optical power in the far-field at a bandwidth of up to 10 kHz. Since the OPA's control system is implemented using field-programmable gate-array technology, the system may be scaled beyond 100 emitters, potentially reaching the kilowatt level optical powers required to perturb the orbit of space debris.

  16. Volume and Mass Estimation of Three-Phase High Power Transformers for Space Applications (United States)

    Kimnach, Greg L.


    Spacecraft historically have had sub-1kW(sub e), electrical requirements for GN&C, science, and communications: Galileo at 600W(sub e), and Cassini at 900W(sub e), for example. Because most missions have had the same order of magnitude power requirements, the Power Distribution Systems (PDS) use existing, space-qualified technology and are DC. As science payload and mission duration requirements increase, however, the required electrical power increases. Subsequently, this requires a change from a passive energy conversion (solar arrays and batteries) to dynamic (alternator, solar dynamic, etc.), because dynamic conversion has higher thermal and conversion efficiencies, has higher power densities, and scales more readily to higher power levels. Furthermore, increased power requirements and physical distribution lengths are best served with high-voltage, multi-phase AC to maintain distribution efficiency and minimize voltage drops. The generated AC-voltage must be stepped-up (or down) to interface with various subsystems or electrical hardware. Part of the trade-space design for AC distribution systems is volume and mass estimation of high-power transformers. The volume and mass are functions of the power rating, operating frequency, the ambient and allowable temperature rise, the types and amount of heat transfer available, the core material and shape, the required flux density in a core, the maximum current density, etc. McLyman has tabulated the performance of a number of transformers cores and derived a "cookbook" methodology to determine the volume of transformers, whereas Schawrze had derived an empirical method to estimate the mass of single-phase transformers. Based on the work of McLyman and Schwarze, it is the intent herein to derive an empirical solution to the volume and mass estimation of three-phase, laminated EI-core power transformers, having radiated and conducted heat transfer mechanisms available. Estimation of the mounting hardware, connectors

  17. Design of a gigawatt space solar power satellite using optical concentrator system (United States)

    Dessanti, B.; Komerath, N.; Shah, S.

    A 1-gigawatt space solar power satellite using a large array of individually pointable optical elements is identified as the key mass element of a large scale space solar power architecture using the Space Power Grid concept. The proposed satellite design enables a significant increase in specific power. Placed in sun-synchronous dynamic orbits near 2000km altitude, these satellites can maintain the constant solar view requirement of GEO-based architectures, while greatly reducing the beaming distance required, decreasing the required antenna size and in turn the overall system mass. The satellite uses an array of individually pointable optical elements (which we call a Mirasol Concentrator Array) to concentrate solar energy to an intensified feed target that feeds into the main heater of the spacecraft, similar conceptually to heliostat arrays. The spacecraft then utilizes Brayton cycle conversion to take advantage of non-linear power level scaling in order to generate high specific power values. Using phase array antennas, the power is then beamed at a millimeter wave frequency of 220GHz down to Earth. The design of the Mirasol concentrator system will be described and a detailed mass estimation of the system is developed. The technical challenges of pointing the elements and maintaining constant solar view is investigated. An end-to-end efficiency analysis is performed. Subsystem designs for the spacecraft are outlined. A detailed mass budget is refined to reflect reductions in uncertainty of the spacecraft mass, particularly in the Mirasol system. One of the key mass drivers of the spacecraft is the active thermal control system. The design of a lightweight thermal control system utilizing graphene sheets is also detailed.

  18. Galaxy bimodality versus stellar mass and environment

    CERN Document Server

    Baldry, I; Bower, R; Glazebrook, K; Nichol, R; Bamford, S; Budavari, T


    We analyse a z<0.1 galaxy sample from the Sloan Digital Sky Survey focusing on the variation of the galaxy colour bimodality with stellar mass and projected neighbour density Sigma, and on measurements of the galaxy stellar mass functions. The characteristic mass increases with environmental density from about 10^10.6 Msun to 10^10.9 Msun (Kroupa IMF, H_0=70) for Sigma in the range 0.1--10 per Mpc^2. The galaxy population naturally divides into a red and blue sequence with the locus of the sequences in colour-mass and colour-concentration index not varying strongly with environment. The fraction of galaxies on the red sequence is determined in bins of 0.2 in log Sigma and log mass (12 x 13 bins). The red fraction f_r generally increases continuously in both Sigma and mass such that there is a unified relation: f_r = F(Sigma,mass). Two simple functions are proposed which provide good fits to the data. These data are compared with analogous quantities in semi-analytical models based on the Millennium N-body ...

  19. Intelligent agents: adaptation of autonomous bimodal microsystems (United States)

    Smith, Patrice; Terry, Theodore B.


    Autonomous bimodal microsystems exhibiting survivability behaviors and characteristics are able to adapt dynamically in any given environment. Equipped with a background blending exoskeleton it will have the capability to stealthily detect and observe a self-chosen viewing area while exercising some measurable form of selfpreservation by either flying or crawling away from a potential adversary. The robotic agent in this capacity activates a walk-fly algorithm, which uses a built in multi-sensor processing and navigation subsystem or algorithm for visual guidance and best walk-fly path trajectory to evade capture or annihilation. The research detailed in this paper describes the theoretical walk-fly algorithm, which broadens the scope of spatial and temporal learning, locomotion, and navigational performances based on optical flow signals necessary for flight dynamics and walking stabilities. By observing a fly's travel and avoidance behaviors; and, understanding the reverse bioengineering research efforts of others, we were able to conceptualize an algorithm, which works in conjunction with decisionmaking functions, sensory processing, and sensorimotor integration. Our findings suggest that this highly complex decentralized algorithm promotes inflight or terrain travel mobile stability which is highly suitable for nonaggressive micro platforms supporting search and rescue (SAR), and chemical and explosive detection (CED) purposes; a necessity in turbulent, non-violent structured or unstructured environments.

  20. Bi-Modal Methods: An Overview

    Directory of Open Access Journals (Sweden)

    Olatunji K. A


    Full Text Available Various security challenges such as Boko Haram, theft, kidnapping, ISIL, abduction, and so on have been on a high rise as one of the major menace facing our society today. In order to overcome these challenges there is need for identification of the culprits to bring them to book. Uni-modal biometric is not enough to combat these security challenges because of its shortcomings which include- spoof attach, noise in the sensed data, inter class variation and so on. Combining two or more biometric features (bi-modal has been proved to provide better performance than uni-modal biometric approach for authentication and verification. This paper presents some literature on biometrics systems that can be employed in achieving a better accuracy in authentication and verification of biometric features. Different kind of fusion strategies to combine these characteristics, different available classifiers and fusion methodologies to achieve greater and accurate recognition performance were also discussed. It is hopeful that researchers in the area of biometrics will find this work very useful.

  1. Audiovisual bimodal mutual compensation of Chinese

    Institute of Scientific and Technical Information of China (English)


    The perception of human languages is inherently a multi-modalprocess, in which audio information can be compensated by visual information to improve the recognition performance. Such a phenomenon in English, German, Spanish and so on has been researched, but in Chinese it has not been reported yet. In our experiment, 14 syllables (/ba, bi, bian, biao, bin, de, di, dian, duo, dong, gai, gan, gen, gu/), extracted from Chinese audiovisual bimodal speech database CAVSR-1.0, were pronounced by 10 subjects. The audio-only stimuli, audiovisual stimuli, and visual-only stimuli were recognized by 20 observers. The audio-only stimuli and audiovisual stimuli both were presented under 5 conditions: no noise, SNR 0 dB, -8 dB, -12 dB, and -16 dB. The experimental result is studied and the following conclusions for Chinese speech are reached. Human beings can recognize visual-only stimuli rather well. The place of articulation determines the visual distinction. In noisy environment, audio information can remarkably be compensated by visual information and as a result the recognition performance is greatly improved.

  2. Audiovisual bimodal mutual compensation of Chinese

    Institute of Scientific and Technical Information of China (English)

    ZHOU; Zhi


    [1]Richard, P., Schumeyer, Kenneth E. B., The effect of visual information on word initial consonant perception of dysarthric speech, in Proc. ICSLP'96 October 3-6 1996, Philadephia, Pennsylvania, USA.[2]Goff, B. L., Marigny, T. G., Benoit, C., Read my lips...and my jaw! How intelligible are the components of a speaker's face? Eurospeech'95, 4th European Conference on Speech Communication and Technology, Madrid, September 1995.[3]McGurk, H., MacDonald, J. Hearing lips and seeing voices, Nature, 1976, 264: 746.[4]Duran A. F., Mcgurk effect in Spanish and German listeners: Influences of visual cues in the perception of Spanish and German confliction audio-visual stimuli, Eurospeech'95. 4th European Conference on Speech Communication and Technology, Madrid, September 1995.[5]Luettin, J., Visual speech and speaker recognition, Ph.D thesis, University of Sheffield, 1997.[6]Xu Yanjun, Du Limin, Chinese audiovisual bimodal speech database CAVSR1.0, Chinese Journal of Acoustics, to appear.[7]Zhang Jialu, Speech corpora and language input/output methods' evaluation, Chinese Applied Acoustics, 1994, 13(3): 5.

  3. 航天电源技术研究进展%Progress of space power technology

    Institute of Scientific and Technical Information of China (English)

    杨紫光; 叶芳; 郭航; 马重芳


    航天电源具备高能量密度、高可靠性、长时间供电等特点,近年来多种航天电源发展迅速。本文介绍了再生型燃料电池、锂离子蓄电池等新型化学能源,新型的太阳能电池技术,太阳能热动力发电系统和核能热发电系统的现状;着重阐述了在航天飞行器上应用的化学蓄电池、太阳能电池阵-蓄电池组、燃料电池、核能发电系统等电源系统的特点及存在的问题。对于航天电源运控相关的流动与传热问题做了深入探讨,并展望了航天电源的研究方向:太阳能电池有向薄膜化方向发展的趋势,化学蓄电池主要配合太阳能电池;燃料电池适用于长时间远距离活动;核能适用大功率、长航时航天器。%The space power is required for high energy density,high reliability and long running time. The research of new energy technologies has drawn a great attention.This paper describes the development of these technologies,including new chemical energy as regenerative fuel cell(RFC), lithium-ion batteries;new solar photovoltaic;solar and nuclear dynamic with high and long running power.And it is focused on the characteristics and the problem in these application space power systems:accumulators,solar array-accumulators,fuel cells and nuclear power,etc.The flow and heat transfer of these space power systems are described in this paper.Also,this paper has some future view on the space power:solar cells have the development for the thin film,chemical power need the breakthrough of the new technology,the progress of the nuclear and solar dynamic power technology are essential to the long-running and high power in space.

  4. Status of an advanced radioisotope space power system using free-piston Stirling technology

    Energy Technology Data Exchange (ETDEWEB)

    White, M.A,; Qiu, S.; Erbeznik, R.M.; Olan, R.W.; Welty, S.C.


    This paper describes a free-piston Stirling engine technology project to demonstrate a high efficiency power system capable of being further developed for deep space missions using a radioisotope (RI) heat source. The key objective is to develop a power system with an efficiency exceeding 20% that can function with a high degree of reliability for 10 years or longer on deep space missions. Primary issues being addressed for Stirling space power systems are weight and the vibration associated with reciprocating pistons. Similar weight and vibration issues have been successfully addressed with Stirling cryocoolers, which are the accepted standard for cryogenic cooling in space. Integrated long-life Stirling engine-generator (or convertor) operation has been demonstrated by the terrestrial Radioisotope Stirling Generator (RSG) and other Stirling Technology Company (STC) programs. Extensive RSG endurance testing includes more than 40,000 maintenance-free, degradation-free hours for the complete convertor, in addition to several critical component and subsystem endurance tests. The Stirling space power convertor project is being conducted by STC under DOE Contract, and NASA SBIR Phase II contracts. The DOE contract objective is to demonstrate a two-convertor module that represents half of a nominal 150-W(e) power system. Each convertor is referred to as a Technology Demonstration Convertor (TDC). The ultimate Stirling power system would be fueled by three general purpose heat source (GPHS) modules, and is projected to produce substantially more electric power than the 150-watt target. The system is capable of full power output with one failed convertor. One NASA contract, nearing completion, uses existing 350-W(e) RG-350 convertors to evaluate interactivity of two back-to-back balanced convertors with various degrees of electrical and mechanical interaction. This effort has recently provided the first successful synchronization of two convertors by means of parallel

  5. Fluoride-assisted synthesis of bimodal microporous SSZ-13 zeolite

    NARCIS (Netherlands)

    Zhu, Xiaochun; Kosinov, Nikolay; Hofmann, Jan P.; Mezari, Brahim; Qian, Qingyun; Rohling, Roderigh; Weckhuysen, Bert M.; Ruiz-Martinez, Javier; Hensen, Emiel J. M.


    The presence of small amount of fluoride in alkaline hydrothermal synthesis of SSZ-13 zeolite yields bimodal microporous particles with substantially improved performance in the methanol-to-olefins (MTO) reaction. Hydrocarbon uptake measurements and fluorescence microspectroscopy of spent catalysts

  6. Functionalized bimodal mesoporous silicas as carriers for controlled aspirin delivery (United States)

    Gao, Lin; Sun, Jihong; Li, Yuzhen


    The bimodal mesoporous silica modified with 3-aminopropyltriethoxysilane was performed as the aspirin carrier. The samples' structure, drug loading and release profiles were characterized with X-ray diffraction, scanning electron microscopy, N 2 adsorption and desorption, Fourier transform infrared spectroscopy, TG analysis, elemental analysis and UV-spectrophotometer. For further exploring the effects of the bimodal mesopores on the drug delivery behavior, the unimodal mesoporous material MCM-41 was also modified as the aspirin carrier. Meantime, Korsmeyer-Peppas equation ft= ktn was employed to analyze the dissolution data in details. It is indicated that the bimodal mesopores are beneficial for unrestricted drug molecules diffusing and therefore lead to a higher loading and faster releasing than that of MCM-41. The results show that the aspirin delivery properties are influenced considerably by the mesoporous matrix, whereas the large pore of bimodal mesoporous silica is the key point for the improved controlled-release properties.

  7. Reactive Sintering of Bimodal WC-Co Hardmetals

    Directory of Open Access Journals (Sweden)

    Marek Tarraste


    Full Text Available Bimodal WC-Co hardmetals were produced using novel technology - reactive sintering. Milled and activated tungsten and graphite powders were mixed with commercial coarse grained WC-Co powder and then sintered. The microstructure of produced materials was free of defects and consisted of evenly distributed coarse and fine tungsten carbide grains in cobalt binder. The microstructure, hardness and fracture toughness of reactive sintered bimodal WC-Co hardmetals is exhibited. Developed bimodal hardmetal has perspective for demanding wear applications for its increased combined hardness and toughness. Compared to coarse material there is only slight decrease in fracture toughness (K1c is 14.7 for coarse grained and 14.4 for bimodal, hardness is increased from 1290 to 1350 HV units.DOI:

  8. Selected Lessons Learned in Space Shuttle Orbiter Propulsion and Power Subsystems (United States)

    Hernandez, Francisco J.; Martinez, Hugo; Ryan, Abigail; Westover, Shayne; Davies, Frank


    Over its 30 years of space flight history, plus the nearly 10 years of design, development test and evaluation, the Space Shuttle Orbiter is full of lessons learned in all of its numerous and complex subsystems. In the current paper, only selected lessons learned in the areas of the Orbiter propulsion and power subsystems will be described. The particular Orbiter subsystems include: Auxiliary Power Unit (APU), Hydraulics and Water Spray Boiler (WSB), Mechanical Flight Controls, Main Propulsion System (MPS), Fuel Cells and Power Reactant and Storage Devices (PRSD), Orbital Maneuvering System (OMS), Reaction Control System (RCS), Electrical Power Distribution (EPDC), electrical wiring and pyrotechnics. Given the complexity and extensive history of each of these subsystems, and the limited scope of this paper, it is impossible to include most of the lessons learned; instead the attempt will be to present a selected few or key lessons, in the judgment of the authors. Each subsystem is presented separate, beginning with an overview of the hardware and their function, a short description of a few historical problems and their lessons, followed by a more comprehensive table listing of the major subsystem problems and lessons. These tables serve as a quick reference for lessons learned in each subsystem. In addition, this paper will establish common lessons across subsystems as well as concentrate on those lessons which are deemed to have the highest applicability to future space flight programs.

  9. Conventional and Bimodal Nuclear Thermal Rocket (NTR) Artificial Gravity Mars Transfer Vehicle Concepts (United States)

    Borowski, Stanley K.; McCurdy, David R.; Packard, Thomas W.


    A variety of countermeasures have been developed to address the debilitating physiological effects of zero-gravity (0-g) experienced by cosmonauts and astronauts during their approximately 0.5 to 1.2 year long stays in low Earth orbit (LEO). Longer interplanetary flights, combined with possible prolonged stays in Mars orbit, could subject crewmembers to up to approximately 2.5 years of weightlessness. In view of known and recently diagnosed problems associated with 0-g, an artificial gravity (AG) spacecraft offers many advantages and may indeed be an enabling technology for human flights to Mars. A number of important human factors must be taken into account in selecting the rotation radius, rotation rate, and orientation of the habitation module or modules. These factors include the gravity gradient effect, radial and tangential Coriolis forces, along with cross-coupled acceleration effects. Artificial gravity Mars transfer vehicle (MTV) concepts are presented that utilize both conventional NTR, as well as, enhanced bimodal nuclear thermal rocket (BNTR) propulsion. The NTR is a proven technology that generates high thrust and has a specific impulse (Isp) capability of approximately 900 s-twice that of today's best chemical rockets. The AG/MTV concepts using conventional Nuclear Thermal Propulsion (NTP) carry twin cylindrical International Space Station (ISS)- type habitation modules with their long axes oriented either perpendicular or parallel to the longitudinal spin axis of the MTV and utilize photovoltaic arrays (PVAs) for spacecraft power. The twin habitat modules are connected to a central operations hub located at the front of the MTV via two pressurized tunnels that provide the rotation radius for the habitat modules. For the BNTR AG/MTV option, each engine has its own closed secondary helium(He)-xenon (Xe) gas loop and Brayton Rotating Unit (BRU) that can generate 10s of kilowatts (kWe) of spacecraft electrical power during the mission coast phase

  10. Space Molten Salt Reactor Concept for Nuclear Electric Propulsion and Surface Power (United States)

    Eades, M.; Flanders, J.; McMurray, N.; Denning, R.; Sun, X.; Windl, W.; Blue, T.

    Students at The Ohio State University working under the NASA Steckler Grant sought to investigate how molten salt reactors with fissile material dissolved in a liquid fuel medium can be applied to space applications. Molten salt reactors of this kind, built for non-space applications, have demonstrated high power densities, high temperature operation without pressurization, high fuel burn up and other characteristics that are ideal for space fission systems. However, little research has been published on the application of molten salt reactor technology to space fission systems. This paper presents a conceptual design of the Space Molten Salt Reactor (SMSR), which utilizes molten salt reactor technology for Nuclear Electric Propulsion (NEP) and surface power at the 100 kWe to 15 MWe level. Central to the SMSR design is a liquid mixture of LiF, BeF2 and highly enriched U235F4 that acts as both fuel and core coolant. In brief, some of the positive characteristics of the SMSR are compact size, simplified core design, high fuel burn up percentages, proliferation resistant features, passive safety mechanisms, a considerable body of previous research, and the possibility for flexible mission architecture.

  11. A feasibility assessment of magnetic bearings for free-piston Stirling space power converters

    Energy Technology Data Exchange (ETDEWEB)

    Curwen, P.W.; Rao, D.K.; Wilson, D.S. [Mechanical Technology Inc., Latham, NY (United States)


    This report describes work performed by Mechanical Technology Incorporated (MTI) under NASA Contract NAS3-26061, {open_quotes}A Feasibility Assessment of Magnetic Bearings for Free-Piston Stirling Space Engines.{close_quotes} The work was performed over the period from July 1990 through August 1991. The objective of the effort was to assess the feasibility and efficacy of applying magnetic bearings to free-piston Stirling-cycle power conversion machinery of the type currently being evaluated for possible use in future long-term space missions.

  12. A systems engineering approach to automated failure cause diagnosis in space power systems (United States)

    Dolce, James L.; Faymon, Karl A.


    Automatic failure-cause diagnosis is a key element in autonomous operation of space power systems such as Space Station's. A rule-based diagnostic system has been developed for determining the cause of degraded performance. The knowledge required for such diagnosis is elicited from the system engineering process by using traditional failure analysis techniques. Symptoms, failures, causes, and detector information are represented with structured data; and diagnostic procedural knowledge is represented with rules. Detected symptoms instantiate failure modes and possible causes consistent with currently held beliefs about the likelihood of the cause. A diagnosis concludes with an explanation of the observed symptoms in terms of a chain of possible causes and subcauses.

  13. Test-retest reliability of resting-state magnetoencephalography power in sensor and source space. (United States)

    Martín-Buro, María Carmen; Garcés, Pilar; Maestú, Fernando


    Several studies have reported changes in spontaneous brain rhythms that could be used as clinical biomarkers or in the evaluation of neuropsychological and drug treatments in longitudinal studies using magnetoencephalography (MEG). There is an increasing necessity to use these measures in early diagnosis and pathology progression; however, there is a lack of studies addressing how reliable they are. Here, we provide the first test-retest reliability estimate of MEG power in resting-state at sensor and source space. In this study, we recorded 3 sessions of resting-state MEG activity from 24 healthy subjects with an interval of a week between each session. Power values were estimated at sensor and source space with beamforming for classical frequency bands: delta (2-4 Hz), theta (4-8 Hz), alpha (8-13 Hz), low beta (13-20 Hz), high beta (20-30 Hz), and gamma (30-45 Hz). Then, test-retest reliability was evaluated using the intraclass correlation coefficient (ICC). We also evaluated the relation between source power and the within-subject variability. In general, ICC of theta, alpha, and low beta power was fairly high (ICC > 0.6) while in delta and gamma power was lower. In source space, fronto-posterior alpha, frontal beta, and medial temporal theta showed the most reliable profiles. Signal-to-noise ratio could be partially responsible for reliability as low signal intensity resulted in high within-subject variability, but also the inherent nature of some brain rhythms in resting-state might be driving these reliability patterns. In conclusion, our results described the reliability of MEG power estimates in each frequency band, which could be considered in disease characterization or clinical trials.

  14. Space Weather Impact on the European Interconnected Power Transmission System at High Latitudes (United States)

    Piccinelli, Roberta; Krausmann, Elisabeth


    High voltage power transmission grids can suffer outages or blackouts during geomagnetic storms (GMS). More specifically, GMS can inject geomagnetically induced currents (GICs) into the power network. Transformers were identified as the most vulnerable components of the power networks: GICs cause transformers to work in saturation regions generating voltage instabilities and eventually driving the system to collapse. Since GMS are expected to cause more pronounced disturbances at high latitudes, we addressed the effects of extreme GMS on the Scandinavian 400 kV interconnected power transmission grid, including Finland, Sweden and Norway. By applying extreme 100-year-benchmark scenarios, we analyzed potential space-weather triggered voltage instabilities in the power grid considering mono-phase transformers, which are known to be more vulnerable to GIC injection, and three-phase transformers, which are more resistant. We assumed that every node of the grid included either transformers of the mono-phase type, or three-phase transformers.Our simulations indicate that the three-phase configuration of the network is significantly more robust than the mono-phase one. Our study indicates that for a system with only three-phase transformers the likelihood of grid collapse is very low, and collapse only occurs for the worst-case scenario with extremely high geoelectric field intensities. In such a case, the increase in reactive power demand caused by transformer saturation is too high for the system to continue to provide power. Our results indicate that lines that experience higher reactive power losses during normal operation are more likely to increase losses during a GMS event. According to our study, the portion of the Scandinavian interconnected power transmission grid most vulnerable to extreme space weather is the part where the highest reactive losses in transmission lines and in voltage magnitudes are observed. This corresponds to the southern parts of Sweden and

  15. Simulation and Control Lab Development for Power and Energy Management for NASA Manned Deep Space Missions (United States)

    McNelis, Anne M.; Beach, Raymond F.; Soeder, James F.; McNelis, Nancy B.; May, Ryan; Dever, Timothy P.; Trase, Larry


    The development of distributed hierarchical and agent-based control systems will allow for reliable autonomous energy management and power distribution for on-orbit missions. Power is one of the most critical systems on board a space vehicle, requiring quick response time when a fault or emergency is identified. As NASAs missions with human presence extend beyond low earth orbit autonomous control of vehicle power systems will be necessary and will need to reliably function for long periods of time. In the design of autonomous electrical power control systems there is a need to dynamically simulate and verify the EPS controller functionality prior to use on-orbit. This paper presents the work at NASA Glenn Research Center in Cleveland, Ohio where the development of a controls laboratory is being completed that will be utilized to demonstrate advanced prototype EPS controllers for space, aeronautical and terrestrial applications. The control laboratory hardware, software and application of an autonomous controller for demonstration with the ISS electrical power system is the subject of this paper.

  16. Power Management and Distribution Trades Studies for a Deep-Space Mission Scientific Spacecraft (United States)

    Kimnach, Greg L.; Soltis, James V.


    As part of NASA's Project Prometheus, the Nuclear Systems Program, NASA GRC performed trade studies on the various Power Management and Distribution (PMAD) options for a deep-space scientific spacecraft which would have a nominal electrical power requirement of 100 kWe. These options included AC (1000Hz and 1500Hz and DC primary distribution at various voltages. The distribution system efficiency, reliability, mass, thermal, corona, space radiation levels and technology readiness of devices and components were considered. The final proposed system consisted of two independent power distribution channels, sourced by two 3-phase, 110 kVA alternators nominally operating at half-rated power. Each alternator nominally supplies 50kWe to one half of the ion thrusters and science modules but is capable of supplying the total power re3quirements in the event of loss of one alternator. This paper is an introduction to the methodology for the trades done to arrive at the proposed PMAD architecture. Any opinions expressed are those of the author(s) and do not necessarily reflect the views of Project Prometheus.

  17. Lightweight Damage Tolerant Radiators for In-Space Nuclear Electric Power and Propulsion (United States)

    Craven, Paul; SanSoucie, Michael P.; Tomboulian, Briana; Rogers, Jan; Hyers, Robert


    Nuclear electric propulsion (NEP) is a promising option for high-speed in-space travel due to the high energy density of nuclear power sources and efficient electric thrusters. Advanced power conversion technologies for converting thermal energy from the reactor to electrical energy at high operating temperatures would benefit from lightweight, high temperature radiator materials. Radiator performance dictates power output for nuclear electric propulsion systems. Pitch-based carbon fiber materials have the potential to offer significant improvements in operating temperature and mass. An effort at the NASA Marshall Space Flight Center to show that woven high thermal conductivity carbon fiber mats can be used to replace standard metal and composite radiator fins to dissipate waste heat from NEP systems is ongoing. The goals of this effort are to demonstrate a proof of concept, to show that a significant improvement of specific power (power/mass) can be achieved, and to develop a thermal model with predictive capabilities. A description of this effort is presented.

  18. Space-time wind speed forecasting for improved power system dispatch

    KAUST Repository

    Zhu, Xinxin


    To support large-scale integration of wind power into electric energy systems, state-of-the-art wind speed forecasting methods should be able to provide accurate and adequate information to enable efficient, reliable, and cost-effective scheduling of wind power. Here, we incorporate space-time wind forecasts into electric power system scheduling. First, we propose a modified regime-switching, space-time wind speed forecasting model that allows the forecast regimes to vary with the dominant wind direction and with the seasons, hence avoiding a subjective choice of regimes. Then, results from the wind forecasts are incorporated into a power system economic dispatch model, the cost of which is used as a loss measure of the quality of the forecast models. This, in turn, leads to cost-effective scheduling of system-wide wind generation. Potential economic benefits arise from the system-wide generation of cost savings and from the ancillary service cost savings. We illustrate the economic benefits using a test system in the northwest region of the United States. Compared with persistence and autoregressive models, our model suggests that cost savings from integration of wind power could be on the scale of tens of millions of dollars annually in regions with high wind penetration, such as Texas and the Pacific northwest. © 2014 Sociedad de Estadística e Investigación Operativa.

  19. The Use of Software Agents for Autonomous Control of a DC Space Power System (United States)

    May, Ryan D.; Loparo, Kenneth A.


    In order to enable manned deep-space missions, the spacecraft must be controlled autonomously using on-board algorithms. A control architecture is proposed to enable this autonomous operation for an spacecraft electric power system and then implemented using a highly distributed network of software agents. These agents collaborate and compete with each other in order to implement each of the control functions. A subset of this control architecture is tested against a steadystate power system simulation and found to be able to solve a constrained optimization problem with competing objectives using only local information.

  20. The Design and Life Test of a Multifunction Power Amplifier for Space Application

    Directory of Open Access Journals (Sweden)

    Xiuqin Xu


    Full Text Available A new multifunction power amplifier (MFPA is designed and fabricated for the application of point-to-point K-Band backhaul TR module. A DC temperature life test was performed to model the up-limit temperature effect of the designed MFPA under space application. After 240 hours of 100°C life test, the test results illustrate that the designed MFPA has only slight power degradation at the saturation region without change of the linear gain. The general performance of the designed MFPA satisfies the requirement of the application scenario.

  1. Dynamic characteristics of power-tower space stations with 15-foot truss bays (United States)

    Dorsey, J. T.


    A power tower space station concept which generates power with photovoltaic arrays and where the truss structure has a bay size of 15 ft is described. Rigid body and flexible body dynamic characteristics are presented for a 75-kW Initial Operating Capability (IOC) and 150-kW and 300-kW growth stations. The transient response of the IOC and 300-kW growth stations to shuttle dock, orbit reboost, and mobile remote manipulator system translation loads are studied. Displacements, accelerations, and bending moments at various locations on the IOC and 300-kW growth stations are presented.

  2. OAST Space Theme Workshop. Volume 3: Working group summary. 6: Power (P-2). A. Statement. B. Technology needs (form 1). C. Priority assessment (form 2) (United States)


    Power requirements for the multipurpose space power platform, for space industrialization, SETI, the solar system exploration facility, and for global services are assessed for various launch dates. Priorities and initiatives for the development of elements of space power systems are described for systems using light power input (solar energy source) or thermal power input, (solar, chemical, nuclear, radioisotopes, reactors). Systems for power conversion, power processing, distribution and control are likewise examined.

  3. Wind speed analysis in La Vainest, Mexico: a bimodal probability distribution case

    Energy Technology Data Exchange (ETDEWEB)

    Jaramillo, O.A.; Borja, M.A. [Energias No Convencionales, Morelos (Mexico). Instituto de Investigaciones Electricas


    The statistical characteristics of the wind speed in La Vainest, Oxoic, Mexico, have been analyzed by using wind speed data recorded by Instituto de Investigaciones Electricas (IIE). By grouping the observations by annual, seasonal and wind direction, we show that the wind speed distribution, with calms included, is not represented by the typical two-parameter Weibull function. A mathematical formulation by using a bimodal Weibull and Weibull probability distribution function (PDF) has been developed to analyse the wind speed frequency distribution in that region. The model developed here can be applied for similar regions where the wind speed distribution presents a bimodal PDF. The two-parameter Weibull wind speed distribution must not be generalised, since it is not accurate to represent some wind regimes as the case of La Ventosa, Mexico. The analysis of wind data shows that computing the capacity factor for wind power plants to be installed in La Ventosa must be carded out by means of a bimodal PDF instead of the typical Weibull PDF. Otherwise, the capacity factor will be underestimated. (author)

  4. An integral solar power and propulsion system concept for commercial space applications

    Energy Technology Data Exchange (ETDEWEB)

    Choong, P.T.S. [California International Power Associates, Los Altos Hills, CA (United States)


    An integral space power concept deriving both the electrical and propulsion power from a common high-temperature heat source module offers superior performance capabilities over conventional chemical upper-stage propulsion with separate solar photovoltaic power systems. This hybrid system concept is based on a high efficiency solar concentrator-heated propulsion and a high temperature thermionic technology derived from the proven Solar Energy Thermionics (SET) or the advanced Hydrogen Thermo-ElectroChemical Conversion (HYTEC) for electrical power generation. The thermal hydrogen propulsion technology is derived from the NERVA rocket program. The integral system is capable of long-life power operation at an efficiency of at least twice the conventional photovoltaic approach. Because of anticipated high conversion efficiency of the HYTEC, the electrical power output can be increased several folds using the similarly sized solar concentrator. The propulsion module is capable of high specific impulse during the orbital transfer thrusting. The same module is also usable for long-term orbit management applications. The resulting savings in propellant and power generator equipment enable the use of new generation of low-cost launchers for many commercial satellite applications.

  5. Impact of Radiation Hardness and Operating Temperatures of Silicon Carbide Electronics on Space Power System Mass (United States)

    Juhasz, Albert J.; Tew, Roy C.; Schwarze, Gene E.


    The effect of silicon carbide (SiC) electronics operating temperatures on Power Management and Distribution (PMAD), or Power Conditioning (PC), subsystem radiator size and mass requirements was evaluated for three power output levels (100 kW(e) , 1 MW(e), and 10 MW(e)) for near term technology ( i.e. 1500 K turbine inlet temperature) Closed Cycle Gas Turbine (CCGT) power systems with a High Temperature Gas Reactor (HTGR) heat source. The study was conducted for assumed PC radiator temperatures ranging from 370 to 845 K and for three scenarios of electrical energy to heat conversion levels which needed to be rejected to space by means of the PC radiator. In addition, during part of the study the radiation hardness of the PC electronics was varied at a fixed separation distance to estimate its effect on the mass of the instrument rated reactor shadow shield. With both the PC radiator and the conical shadow shield representing major components of the overall power system the influence of the above on total power system mass was also determined. As expected, results show that the greatest actual mass savings achieved by the use of SiC electronics occur with high capacity power systems. Moreover, raising the PC radiator temperature above 600 K yields only small additional system mass savings. The effect of increased radiation hardness on total system mass is to reduce system mass by virtue of lowering the shield mass.


    Energy Technology Data Exchange (ETDEWEB)

    Du, Z. L., E-mail: [Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)


    Some properties of the 11 yr solar cycle can be explained by the current solar dynamo models. However, some other features remain not well understood such as the asymmetry of the cycle, the double-peaked structure, and the “Waldmeier effect” that a stronger cycle tends to have less rise time and a shorter cycle length. We speculate that the solar cycle is governed by a bi-dynamo model forming two stochastic processes depicted by a bimodal Gaussian function with a time gap of about 2 yr, from which the above features can be reasonably explained. The first one describes the main properties of the cycle dominated by the current solar dynamo models, and the second one occurs either in the rising phase as a short weak explosive perturbation or in the declining phase as a long stochastic perturbation. The above function is the best one selected from several in terms of the Akaike information criterion. Through analyzing different distributions, one might speculate about the dominant physical process inside the convection zone. The secondary (main) process is found to be closely associated with complicated (simple) active ranges. In effect, the bi-dynamo model is a reduced form of a multi-dynamo model, which could occur from the base of the convection zone through its envelope and from low to high heliographic latitude, reflecting the active belts in the convection zone. These results are insensitive to the hemispheric asymmetry, smoothing filters, and distribution functions selected and are expected to be helpful in understanding the formation of solar and stellar cycles.

  7. DynMo: Dynamic Simulation Model for Space Reactor Power Systems (United States)

    El-Genk, Mohamed; Tournier, Jean-Michel


    A Dynamic simulation Model (DynMo) for space reactor power systems is developed using the SIMULINK® platform. DynMo is modular and could be applied to power systems with different types of reactors, energy conversion, and heat pipe radiators. This paper presents a general description of DynMo-TE for a space power system powered by a Sectored Compact Reactor (SCoRe) and that employs off-the-shelf SiGe thermoelectric converters. SCoRe is liquid metal cooled and designed for avoidance of a single point failure. The reactor core is divided into six equal sectors that are neutronically, but not thermal-hydraulically, coupled. To avoid a single point failure in the power system, each reactor sector has its own primary and secondary loops, and each loop is equipped with an electromagnetic (EM) pump. A Power Conversion assembly (PCA) and a Thermoelectric Conversion Assembly (TCA) of the primary and secondary EM pumps thermally couple each pair of a primary and a secondary loop. The secondary loop transports the heat rejected by the PCA and the pumps TCA to a rubidium heat pipes radiator panel. The primary loops transport the thermal power from the reactor sector to the PCAs for supplying a total of 145-152 kWe to the load at 441-452 VDC, depending on the selections of the primary and secondary liquid metal coolants. The primary and secondary coolant combinations investigated are lithium (Li)/Li, Li/sodium (Na), Na-Na, Li/NaK-78 and Na/NaK-78, for which the reactor exit temperature is kept below 1250 K. The results of a startup transient of the system from an initial temperature of 500 K are compared and discussed.

  8. Air and Space Power Journal. Volume 30, Number 3, Fall 2016 (United States)


    systems to find their vulnerabilities and weaknesses . They use the same techniques as real-world attackers and provide an invaluable service in not...crossing of his chemical-weapons-use red line, a perceived weak response to the annexation of Ukrainian sovereign territory by Russian forces, and...much slower; unable to break the sound barrier, the A-10 has a maxi - 48 | Air & Space Power Journal Kaaoush mum speed of a humble 400 knots.64 Having

  9. A Reliability Improvement Program Planning Report for the SNAP 10A Space Nuclear Power Unit

    Energy Technology Data Exchange (ETDEWEB)

    Coombs, M. G.; Smith, C. K.; Wilson, L. A.


    The estimated achieved reliability of SNAP 10A space nuclear power units will be relatively low at the timeof the first SNAPSHOT flight test in April 1963 and the existing R&D program does not provide a significant reliabiity growth thereafter. The total costs of an 8-satellite network using SNAP 10A units over a 5-year period has been approximated for the case where the total cost of a single satellite launched is 8 million dollars.

  10. Mission Analysis and Design for Space Based Inter-Satellite Laser Power Beaming (United States)


    20]. Finally, as shown in Figure 2.1, 1891 saw Nikola Tesla file for U.S. Patent No. 454,622 “System of Electric Lighting”. At the World Columbian...Laser-Beamer Power . Tech- nical Report 2014/34883, Jet Propulsion Laboratory, February 1993. 14. Aldrich, Lisa J. Nikola Tesla and the Taming of... Tesla , Nikola . “The Transmission of Electrical Energy without Wires,” Electrical World and Engineer (March 1904). 33. Tribble, Alan C. The Space

  11. Ultrahigh temperature vapor core reactor-MHD system for space nuclear electric power (United States)

    Maya, Isaac; Anghaie, Samim; Diaz, Nils J.; Dugan, Edward T.


    The conceptual design of a nuclear space power system based on the ultrahigh temperature vapor core reactor with MHD energy conversion is presented. This UF4 fueled gas core cavity reactor operates at 4000 K maximum core temperature and 40 atm. Materials experiments, conducted with UF4 up to 2200 K, demonstrate acceptable compatibility with tungsten-molybdenum-, and carbon-based materials. The supporting nuclear, heat transfer, fluid flow and MHD analysis, and fissioning plasma physics experiments are also discussed.

  12. Space- and Earth-based solar power for the growing energy needs of future generations (United States)

    Seboldt, Wolfgang


    The future global supply with terrestrial regenerative energies (solar, wind, hydro and geothermal) is discussed and compared to energy from space via Solar Power Satellites. It is shown that both have the potential to satisfy global energy needs. Obviously, regenerative solutions must be taken into account and installed with higher priority within the next decades to reduce the deposition of CO 2 into the atmosphere. This is absolutely necessary to stabilize the climate. In addition, the threatening depletion of fossil and nuclear fuels in the long run forces research into alternative solutions. Concerning solar power from space, the recently developed concepts for light-weight inflatable and deployable solar arrays/concentrators—like in the NASA 'Sun Tower' and the 'European Sail Tower SPS'—are reviewed and major problems with wireless power transmission are discussed. Compared to earlier concepts the designs have the potential to reduce significantly the masses and, thus, the costs. But the technological demands and operational uncertainties are still immense. Anyhow, major progress with cost reductions of one to two orders of magnitude is required for the space option to become competitive with terrestrial regenerative options.

  13. Status update of a free-piston Stirling convertor for radioisotope space power systems (United States)

    White, Maurice; Qiu, Songgang; Augenblick, Jack; Peterson, Allen; Faultersack, Frank


    Free-piston Stirling engines offer a relatively mature technology that is well-suited for advanced, high-efficiency radioisotope space power systems. This paper updates results from a combination of DOE and NASA contracts with Stirling Technology Company (STC). These contracts have demonstrated STC's Stirling convertor technology in a configuration and power level representative of a space power system. Based on demonstrated performance, long-life maintenance-free technology heritage, and success with aggressively imposed vibration testing. DOE has awarded system integration contracts to Boeing, Lockheed Martin and Teledyne Energy Systems. The objectives of these competitive Phase I contracts are to develop complete spacecraft power system conceptual designs based on the STC Stirling convertor, and to plan subsequent phases for two launches. Performance results for the DOE 55-W(e) Technology Demonstration Convertors (TDC's) have met original projections. Although the TDC's were intended only for technology demonstration, they have achieved very aggressive efficiency goals, demonstrated convertor-induced vibration levels below the Jet Propulsion Laboratory (JPL) specifications, passed a simulated launch load vibration test at 0.2 g2/Hz (12.3 g rms), and met EMI/EMC goals for most contemplated missions. No consideration for EMI reduction was included in the TDC design. Minor changes are underway to reduce EMI levels, with a goal of meeting specifications for missions such as Solar Probe with highly sensitive instrumentation. The long-term objective for DOE is to develop a power system with a system efficiency exceeding 20% that can function with a high degree of reliability for 10 years and longer on deep space missions. .

  14. Rapid modelling of the redshift-space power spectrum multipoles for a masked density field (United States)

    Wilson, M. J.; Peacock, J. A.; Taylor, A. N.; de la Torre, S.


    In this work, we reformulate the forward modelling of the redshift-space power spectrum multipole moments for a masked density field, as encountered in galaxy redshift surveys. Exploiting the symmetries of the redshift-space correlation function, we provide a masked-field generalization of the Hankel transform relation between the multipole moments in real and Fourier space. Using this result, we detail how a likelihood analysis requiring computation for a broad range of desired P(k) models may be executed 103-104 times faster than with other common approaches, together with significant gains in spectral resolution. We present a concrete application to the complex angular geometry of the VIMOS Public Extragalactic Redshift Survey PDR-1 release and discuss the validity of this technique for finite-angle surveys.

  15. The scalability of OTR (out-of-core thermionic reactor) space nuclear power systems

    Energy Technology Data Exchange (ETDEWEB)

    Gallup, D.R.


    In this document, masses of the STAR-C power system and an optimized out-of-core thermionic reactor (OTR) power system versus power level are investigated. The impacts of key system parameters on system performance are also addressed. The STAR-C is mass competitive below about 15 kWe, but at higher power levels the scalability is relatively poor. An optimized OR is the least massive space nuclear power system below 25 kWe, and scales well to 50 kWe. The system parameters that have a significant impact on the scalability of the STAR-C are core thermal flux, thermionic converter efficiency, and core length to diameter ratio. The emissivity of the core surface is shown to be a relatively unimportant parameter. For an optimized OR power system, the most significant system parameter is the maximum allowable fuel temperature. It is also shown that if advanced radiation-hardened electronics are used in the satellite payload, a very large mass savings is realized. 10 refs., 23 figs., 7 tabs.

  16. Multi-MW Closed Cycle MHD Nuclear Space Power Via Nonequilibrium He/Xe Working Plasma (United States)

    Litchford, Ron J.; Harada, Nobuhiro


    Prospects for a low specific mass multi-megawatt nuclear space power plant were examined assuming closed cycle coupling of a high-temperature fission reactor with magnetohydrodynamic (MHD) energy conversion and utilization of a nonequilibrium helium/xenon frozen inert plasma (FIP). Critical evaluation of performance attributes and specific mass characteristics was based on a comprehensive systems analysis assuming a reactor operating temperature of 1800 K for a range of subsystem mass properties. Total plant efficiency was expected to be 55.2% including plasma pre-ionization power, and the effects of compressor stage number, regenerator efficiency and radiation cooler temperature on plant efficiency were assessed. Optimal specific mass characteristics were found to be dependent on overall power plant scale with 3 kg/kWe being potentially achievable at a net electrical power output of 1-MWe. This figure drops to less than 2 kg/kWe when power output exceeds 3 MWe. Key technical issues include identification of effective methods for non-equilibrium pre-ionization and achievement of frozen inert plasma conditions within the MHD generator channel. A three-phase research and development strategy is proposed encompassing Phase-I Proof of Principle Experiments, a Phase-II Subscale Power Generation Experiment, and a Phase-III Closed-Loop Prototypical Laboratory Demonstration Test.

  17. The potential impact of new power system technology on the design of a manned Space Station (United States)

    Fordyce, J. S.; Schwartz, H. J.


    Larger, more complex spacecraft of the future such as a manned Space Station will require electric power systems of 100 kW and more, orders of magnitude greater than the present state of the art. Power systems at this level will have a significant impact on the spacecraft design. Historically, long-lived spacecraft have relied on silicon solar cell arrays, a nickel-cadmium storage battery and operation at 28 V dc. These technologies lead to large array areas and heavy batteries for a Space Station application. This, in turn, presents orbit altitude maintenance, attitude control, energy management and launch weight and volume constraints. Size (area) and weight of such a power system can be reduced if new higher efficiency conversion and lighter weight storage technologies are used. Several promising technology options including concentrator solar photovoltaic arrays, solar thermal dynamic and ultimately nuclear dynamic systems to reduce area are discussed. Also, higher energy storage systems such as nickel-hydrogen and the regenerative fuel cell (RFC) and higher voltage power distribution which add system flexibility, simplicity and reduce weight are examined. Emphasis placed on the attributes and development status of emerging technologies that are sufficiently developed so that they could be available for flight use in the early to mid 1990's.

  18. Ground test challenges in the development of the Space Shuttle orbiter auxiliary power unit (United States)

    Chaffee, N. H.; Lance, R. J.; Weary, D. P.


    A conventional aircraft hydraulic system design approach was selected to provide fluid power for the Space Shuttle Orbiter. Developing the power unit, known as the Auxiliary Power Unit (APU), to drive the hydraulic pumps presented a major technological challenge. A small, high speed turbine drive unit powered by catalytically decomposed hydrazine and operating in the pulse mode was selected to meet the requirement. Because of limitations of vendor test facilities, significant portions of the development, flight qualification, and postflight anomaly testing of the Orbiter APU were accomplished at the Johnson Space Center (JSC) test facilities. This paper discusses the unique requirements of attitude, gravity forces, pressure profiles, and thermal environments which had to be satisfied by the APU, and presents the unique test facility and simulation techniques employed to meet the ground test requirements. In particular, the development of the zero-g lubrication system, the development of necessary APU thermal control techniques, the accomplishment of integrated systems tests, and the postflight investigation of the APU lube oil cooler behavior are discussed.

  19. Hydrogen turbines for space power systems: A simplified axial flow gas turbine model

    Energy Technology Data Exchange (ETDEWEB)

    Hudson, S.L.


    This paper descirbes a relatively simple axial flow gas expansion turbine mass model, which we developed for use in our space power system studies. The model uses basic engineering principles and realistic physical properties, including gas conditions, power level, and material stresses, to provide reasonable and consistent estimates of turbine mass and size. Turbine design modifications caused by boundary layer interactions, stress concentrations, stage leakage, or bending and thermal stresses are not accounted for. The program runs on an IBM PC, uses little computer time and has been incorporated into our system-level space power platform analysis computer codes. Parametric design studies of hydrogen turbines using this model are presented for both nickel superalloy and carbon/carbon composite turbines. The effects of speed, pressure ratio, and power level on hydrogen turbine mass are shown and compared to a baseline case 100-MWe, 10,000-rpm hydrogen turbine. Comparison with more detailed hydrogen turbine designs indicates that our simplified model provides mass estimates that are within 25% of the ones provided by more complex calculations. 8 figs.

  20. The NASA-Lewis program on fusion energy for space power and propulsion, 1958-1978 (United States)

    Schulze, Norman R.; Roth, J. Reece


    An historical synopsis is provided of the NASA-Lewis research program on fusion energy for space power and propulsion systems. It was initiated to explore the potential applications of fusion energy to space power and propulsion systems. Some fusion related accomplishments and program areas covered include: basic research on the Electric Field Bumpy Torus (EFBT) magnetoelectric fusion containment concept, including identification of its radial transport mechanism and confinement time scaling; operation of the Pilot Rig mirror machine, the first superconducting magnet facility to be used in plasma physics or fusion research; operation of the Superconducting Bumpy Torus magnet facility, first used to generate a toroidal magnetic field; steady state production of neutrons from DD reactions; studies of the direct conversion of plasma enthalpy to thrust by a direct fusion rocket via propellant addition and magnetic nozzles; power and propulsion system studies, including D(3)He power balance, neutron shielding, and refrigeration requirements; and development of large volume, high field superconducting and cryogenic magnet technology.

  1. Gaseous-fuel nuclear reactor research for multimegawatt power in space (United States)

    Thom, K.; Schneider, R. T.; Helmick, H. H.


    In the gaseous-fuel reactor concept, the fissile material is contained in a moderator-reflector cavity and exists in the form of a flowing gas or plasma separated from the cavity walls by means of fluid mechanical forces. Temperatures in excess of structural limitations are possible for low-specific-mass power and high-specific-impulse propulsion in space. Experiments have been conducted with a canister filled with enriched UF6 inserted into a beryllium-reflected cavity. A theoretically predicted critical mass of 6 kg was measured. The UF6 was also circulated through this cavity, demonstrating stable reactor operation with the fuel in motion. Because the flowing gaseous fuel can be continuously processed, the radioactive waste in this type of reactor can be kept small. Another potential of fissioning gases is the possibility of converting the kinetic energy of fission fragments directly into coherent electromagnetic radiation, the nuclear pumping of lasers. Numerous nuclear laser experiments indicate the possibility of transmitting power in space directly from fission energy. The estimated specific mass of a multimegawatt gaseous-fuel reactor power system is from 1 to 5 kg/kW while the companion laser-power receiver station would be much lower in specific mass.

  2. Optimal Solution of the EPED Problem Considering Space Areas of HSABC on the Power System Operation

    Directory of Open Access Journals (Sweden)

    A.N. Afandi


    Full Text Available Recently, the emission problem and economic dispatch (EPED becomes crucial aspects in the power system operation. These aspects are measured technically using financial payments as the total operating cost based on pollutant productions and fuel consumptions throughout individual costs of generating units based on a committed power output to meet a load demand. This paper introduces the newest artificial intelligent computation, harvest season artificial bee colony (HSABC algorithm, for determining the optimal solution of the EPED based on the operating cost function using IEEE-62 bus system with various operational constraints. Results obtained show that HSABC has short time computations and fast convergences while space areas give different implications on performances. The optimal solution produces various individual power outputs, pollutants, and costs.

  3. Charge generation by heavy ions in power MOSFETs, burnout space predictions, and dynamic SEB sensitivity (United States)

    Stassinopoulos, E. G.; Brucker, G. J.; Calvel, P.; Baiget, A.; Peyrotte, C.; Gaillard, R.


    The transport, energy loss, and charge production of heavy ions in the sensitive regions of IRF 150 power MOSFETs are described. The dependence and variation of transport parameters with ion type and energy relative to the requirements for single event burnout in this part type are discussed. Test data taken with this power MOSFET are used together with analyses by means of a computer code of the ion energy loss and charge production in the device to establish criteria for burnout and parameters for space predictions. These parameters are then used in an application to predict burnout rates in a geostationary orbit for power converters operating in a dynamic mode. Comparisons of rates for different geometries in simulating SEU (single event upset) sensitive volumes are presented.

  4. Preliminary Results From NASA's Space Solar Power Exploratory Research and Technology Program (United States)

    Howell, Joe T.; Mankins, John C.


    Large solar power satellite (SPS) systems that might provide base load power into terrestrial markets were examined extensively in the 1970s by the US Department of Energy (DOE) and the National Aeronautics and Space Administration (NASA). Following a hiatus of about 15 years, the subject of space solar power (SSP) was reexamined by NASA from 1995-1997 in the "fresh look" study, and during 1998 in an SSP "concept definition study". As a result of these efforts, during 1999-2000, NASA has been conducting the SSP Exploratory Research and Technology (SERT) program. The goal of the SERT activity has been to conduct preliminary strategic technology research and development to enable large, multi-megawatt SSP systems and wireless power transmission (WPT) for government missions and commercial markets (in-space and terrestrial). In pursuing that goal, the SERT: (1) refined and modeled systems approaches for the utilization of SSP concepts and technologies, ranging from the near-term (e.g., for space science, exploration and commercial space applications) to the far-term (e.g., SSP for terrestrial markets), including systems concepts, architectures, technology, infrastructure (e.g. transportation), and economics; (2) conducted technology research, development and demonstration activities to produce "proof-of-concept" validation of critical SSP elements for both nearer and farther-term applications; and (3) engendered the beginnings of partnerships (nationally and internationally) that could be expanded, as appropriate, to pursue later SSP technology and applications. Through these efforts, the SERT should allow better informed future decisions regarding further SSP and related technology research and development investments by both NASA and prospective partners, and guide further definition of technology roadmaps - including performance objectives, resources and schedules, as well as "multi-purpose" applications (e.g., commerce, science, and government). This paper

  5. U.S. Space Radioisotope Power Systems and Applications: Past, Present and Future (United States)

    Cataldo, Robert L.; Bennett, Gary L.


    Radioisotope power systems (RPS) have been essential to the U.S. exploration of outer space. RPS have two primary uses: electrical power and thermal power. To provide electrical power, the RPS uses the heat produced by the natural decay of a radioisotope (e.g., plutonium-238 in U.S. RPS) to drive a converter (e.g., thermoelectric elements or Stirling linear alternator). As a thermal power source the heat is conducted to whatever component on the spacecraft needs to be kept warm; this heat can be produced by a radioisotope heater unit (RHU) or by using the excess heat of a radioisotope thermoelectric generator (RTG). As of 2010, the U.S. has launched 41 RTGs on 26 space systems. These space systems have ranged from navigational satellites to challenging outer planet missions such as Pioneer 10/11, Voyager 1/2, Galileo, Ulysses, Cassini and the New Horizons mission to Pluto. In the fall of 2011, NASA plans to launch the Mars Science Laboratory (MSL) that will employ the new Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) as the principal power source. Hundreds of radioisotope heater units (RHUs) have been launched to provide warmth to Apollo 11, used to provide heating of critical components in a seismic experiment package, Pioneer 10/11, Voyager 1/2, Galileo, Cassini, Mars Pathfinder, MER rovers, etc. to provide temperature control to critical spacecraft electronics and other mechanical devices such as propulsion system propellant valves. A radioisotope (electrical) power source or system (RPS) consists of three basic elements: (1) the radioisotope heat source that provides the thermal power, (2) the converter that transforms the thermal power into electrical power and (3) the heat rejection radiator. Figure 1 illustrates the basic features of an RPS. The idea of a radioisotope power source follows closely after the early investigations of radioactivity by researchers such as Henri Becquerel (1852-1908), Marie Curie (1867-1935), Pierre Curie (1859

  6. High-Efficiency, High-Power Ka-Band Elliptic-Beam Traveling-Wave-Tube Amplifier for Long-Range Space RF Telecommunications Project (United States)

    National Aeronautics and Space Administration — Space telecommunications require amplifiers that are efficient, high-power, wideband, small, lightweight, and highly reliable. Currently, helix traveling wave tube...

  7. Perception of Sung Speech in Bimodal Cochlear Implant Users (United States)

    Galvin, John J.; Fu, Qian-Jie


    Combined use of a hearing aid (HA) and cochlear implant (CI) has been shown to improve CI users’ speech and music performance. However, different hearing devices, test stimuli, and listening tasks may interact and obscure bimodal benefits. In this study, speech and music perception were measured in bimodal listeners for CI-only, HA-only, and CI + HA conditions, using the Sung Speech Corpus, a database of monosyllabic words produced at different fundamental frequencies. Sentence recognition was measured using sung speech in which pitch was held constant or varied across words, as well as for spoken speech. Melodic contour identification (MCI) was measured using sung speech in which the words were held constant or varied across notes. Results showed that sentence recognition was poorer with sung speech relative to spoken, with little difference between sung speech with a constant or variable pitch; mean performance was better with CI-only relative to HA-only, and best with CI + HA. MCI performance was better with constant words versus variable words; mean performance was better with HA-only than with CI-only and was best with CI + HA. Relative to CI-only, a strong bimodal benefit was observed for speech and music perception. Relative to the better ear, bimodal benefits remained strong for sentence recognition but were marginal for MCI. While variations in pitch and timbre may negatively affect CI users’ speech and music perception, bimodal listening may partially compensate for these deficits. PMID:27837051

  8. Bimodal bilingualism and the frequency-lag hypothesis. (United States)

    Emmorey, Karen; Petrich, Jennifer A F; Gollan, Tamar H


    The frequency-lag hypothesis proposes that bilinguals have slowed lexical retrieval relative to monolinguals and in their nondominant language relative to their dominant language, particularly for low-frequency words. These effects arise because bilinguals divide their language use between 2 languages and use their nondominant language less frequently. We conducted a picture-naming study with hearing American Sign Language (ASL)-English bilinguals (bimodal bilinguals), deaf signers, and English-speaking monolinguals. As predicted by the frequency-lag hypothesis, bimodal bilinguals were slower, less accurate, and exhibited a larger frequency effect when naming pictures in ASL as compared with English (their dominant language) and as compared with deaf signers. For English there was no difference in naming latencies, error rates, or frequency effects for bimodal bilinguals as compared with monolinguals. Neither age of ASL acquisition nor interpreting experience affected the results; picture-naming accuracy and frequency effects were equivalent for deaf signers and English monolinguals. Larger frequency effects in ASL relative to English for bimodal bilinguals suggests that they are affected by a frequency lag in ASL. The absence of a lag for English could reflect the use of mouthing and/or code-blending, which may shield bimodal bilinguals from the lexical slowing observed for spoken language bilinguals in the dominant language.

  9. GPS-Like Phasing Control of the Space Solar Power System Transmission Array (United States)

    Psiaki, Mark L.


    The problem of phasing of the Space Solar Power System's transmission array has been addressed by developing a GPS-like radio navigation system. The goal of this system is to provide power transmission phasing control for each node of the array that causes the power signals to add constructively at the ground reception station. The phasing control system operates in a distributed manner, which makes it practical to implement. A leader node and two radio navigation beacons are used to control the power transmission phasing of multiple follower nodes. The necessary one-way communications to the follower nodes are implemented using the RF beacon signals. The phasing control system uses differential carrier phase relative navigation/timing techniques. A special feature of the system is an integer ambiguity resolution procedure that periodically resolves carrier phase cycle count ambiguities via encoding of pseudo-random number codes on the power transmission signals. The system is capable of achieving phasing accuracies on the order of 3 mm down to 0.4 mm depending on whether the radio navigation beacons operate in the L or C bands.

  10. Dynamic neutronic and stability analysis of a burst mode, single cavity gas core reactor Brayton cycle space power system (United States)

    Dugan, Edward T.; Kutikkad, Kiratadas

    The conceptual, burst-mode gaseous-core reactor (GCR) space nuclear power system presently subjected to reactor-dynamics and system stability studies operates on a closed Brayton cycle, via disk MHD generator for energy conversion. While the gaseous fuel density power coefficient of reactivity is found to be capable of rapidly stabilizing the GCR system, the power of this feedback renders standard external reactivity insertions inadequate for significant power-level changes during normal operation.

  11. Late-time quadrupolar gravitational wave power in de Sitter space (United States)

    Hazboun, Jeffrey


    We have calculated the power emitted by a binary system in a cosmological context modeled by a stress energy source on a de Sitter background. The calculation is based on the quadrupole formula for late-time gravitational waves in de Sitter space put forward by Ashtekar, Bonga and Kesavan. There is little reason to expect, a priori, that the projection operator usually used to find the transverse-traceless components of a tensor in asymptotically flat spaces will accurately characterize the physical degrees of freedom in an asymptotically de Sitter spacetime. Instead we use the differential recipe that is true in general, but cumbersome to solve explicitly. The solution presented is based on a conformally transformed version of the quadrupole moment from a Minkowski spacetime for a stable circular binary. A process for calculating the late time power is presented, which coincides with future null infinity. Progress on time dependent results will also be presented. We will discuss the physicality of these results and compare it to other results for gravitational waves in de Sitter space, including recent results on gravitational wave memory.

  12. Ionizing radiation risks to Satellite Power Systems (SPS) workers in space

    Energy Technology Data Exchange (ETDEWEB)


    A reference Satellite Power System (SPS) has been designed by NASA and its contractors for the purposes of evaluating the concept and carrying out assessments of the various consequences of development, including those on the health of the space workers. The Department of Energy has responsibility for directing various assessments. Present planning calls for the SPS workers to move from Earth to a low earth orbit (LEO) at an altitude of 500 kilometers; to travel by a transfer ellipse (TE) trajectory to a geosynchronous orbit (GEO) at an altitude of 36,000 kilometers; and to remain in GEO orbit for about 90 percent of the total time aloft. The radiation risks to the health of workers who will construct and maintain solar power satellites in the space environment are studied. The charge to the committee was: (a) to evaluate the radiation environment estimated for the Reference System which could represent a hazard; (b) to assess the possible somatic and genetic radiation hazards; and (c) to estimate the risks to the health of SPS workers due to space radiation exposure, and to make recommendations based on these conclusions. Details are presented. (WHK)

  13. Artificial neural network application for space station power system fault diagnosis (United States)

    Momoh, James A.; Oliver, Walter E.; Dias, Lakshman G.


    This study presents a methodology for fault diagnosis using a Two-Stage Artificial Neural Network Clustering Algorithm. Previously, SPICE models of a 5-bus DC power distribution system with assumed constant output power during contingencies from the DDCU were used to evaluate the ANN's fault diagnosis capabilities. This on-going study uses EMTP models of the components (distribution lines, SPDU, TPDU, loads) and power sources (DDCU) of Space Station Alpha's electrical Power Distribution System as a basis for the ANN fault diagnostic tool. The results from the two studies are contrasted. In the event of a major fault, ground controllers need the ability to identify the type of fault, isolate the fault to the orbital replaceable unit level and provide the necessary information for the power management expert system to optimally determine a degraded-mode load schedule. To accomplish these goals, the electrical power distribution system's architecture can be subdivided into three major classes: DC-DC converter to loads, DC Switching Unit (DCSU) to Main bus Switching Unit (MBSU), and Power Sources to DCSU. Each class which has its own electrical characteristics and operations, requires a unique fault analysis philosophy. This study identifies these philosophies as Riddles 1, 2 and 3 respectively. The results of the on-going study addresses Riddle-1. It is concluded in this study that the combination of the EMTP models of the DDCU, distribution cables and electrical loads yields a more accurate model of the behavior and in addition yielded more accurate fault diagnosis using ANN versus the results obtained with the SPICE models.

  14. The Abacus/Reflector and Integrated Symmetrical Concentrator: Concepts for Space Solar Power Collection and Transmission (United States)

    Carrington, Connie; Fikes, John; Gerry, Mark; Perkinson, Don


    New energy sources are vital for the development of emerging nations, and the growth of industry in developed economies. Also vital is the need for these energy sources to be clean and renewable. For the past several years, NASA has been taking a new look at collecting solar energy in space and transmitting it to Earth, to planetary surfaces, and to orbiting spacecraft. Several innovative concepts are being studied for the space segment component of solar power beaming. One is the Abacus/Reflector, a large sun-oriented array structure fixed to the transmitter, and a rotating RF reflector that tracks a receiving rectenna on Earth. This concept eliminates the need for power-conducting slip rings in rotating joints between the solar collectors and the transmitter. Another concept is the Integrated Symmetrical Concentrator (ISC), composed of two very large segmented reflectors which rotate to collect and reflect the incident sunlight onto two centrally-located photovoltaic arrays. Adjacent to the PV arrays is the RF transmitter, which as a unit track the receiving rectenna, again eliminating power-conducting joints, and in addition reducing the cable lengths between the arrays and transmitter. The metering structure to maintain the position of the reflectors is a long mast, oriented perpendicular to the equatorial orbit plane. This paper presents a status of ongoing systems studies and configurations for the Abacus/Reflector and the ISC concepts, and a top-level study of packaging for launch and assembly.

  15. Physics and potentials of fissioning plasmas for space power and propulsion (United States)

    Thom, K.; Schwenk, F. C.; Schneider, R. T.


    Fissioning uranium plasmas are the nuclear fuel in conceptual high-temperature gaseous-core reactors for advanced rocket propulsion in space. A gaseous-core nuclear rocket would be a thermal reactor in which an enriched uranium plasma at about 10,000 K is confined in a reflector-moderator cavity where it is nuclear critical and transfers its fission power to a confining propellant flow for the production of thrust at a specific impulse up to 5000 sec. With a thrust-to-engine weight ratio approaching unity, the gaseous-core nuclear rocket could provide for propulsion capabilities needed for manned missions to the nearby planets and for economical cislunar ferry services. Fueled with enriched uranium hexafluoride and operated at temperatures lower than needed for propulsion, the gaseous-core reactor scheme also offers significant benefits in applications for space and terrestrial power. They include high-efficiency power generation at low specific mass, the burnup of certain fission products and actinides, the breeding of U-233 from thorium with short doubling times, and improved convenience of fuel handling and processing in the gaseous phase.

  16. A hypothesis for the color bimodality of Jupiter Trojans

    CERN Document Server

    Wong, Ian


    One of the most enigmatic and hitherto unexplained properties of Jupiter Trojans is their bimodal color distribution. This bimodality is indicative of two sub-populations within the Trojans, which have distinct size distributions. In this paper, we present a simple, plausible hypothesis for the origin and evolution of the two Trojan color sub-populations. In the framework of dynamical instability models of early Solar System evolution, which suggest a common primordial progenitor population for both Trojans and Kuiper belt objects, we use observational constraints to assert that the color bimodalities evident in both minor body populations developed within the primordial population prior to the onset of instability. We show that, beginning with an initial composition of rock and ices, location-dependent volatile loss through sublimation in this primordial population could have led to sharp changes in the surface composition with heliocentric distance. We propose that the depletion or retention of H$_{2}$S ice...

  17. Population Pressure, Global Living Standards, and the Promise of Space Solar Power (United States)

    Strickland, John K., Jr.


    uses of electricity and fuels currently covered by fossil fuels. This is a global replacement load of about 9000 gigawatts. Green theorists are divided on this issue. Some claim that ground based solar, wind, and other renewable sources will supply all the energy we need, ignoring economic costs that severely limit their use. Others would (unrealistically) require the developed countries to reduce their energy consumption per capita to a level closer to that of the developing world, thereby admitting the limitations of the "appropriate" systems they espouse. Both sides in the past have rejected as "non-appropriate" and/or "dangerous" all the chemically clean energy sources of high capacity that have been previously proposed, such as safer nuclear fission, fusion power, and space solar power. If ground based "appropriate" energy sources are not sufficient, the economic and social effects of sudden forced curtailments of fossil energy use could be drastic. This paper supports the thesis that Space Solar Power does have the potential to provide such a clean, abundant, and economical energy source. It will cover both the limitations and promise of ground based energy sources, including the difficulties of using intermittent energy sources. It will discuss whether specified levels of energy cost increases would be damaging to the world economy and whether economical ground based sources alone would have sufficient capacity. It will show how the one major problem of launch costs, (currently preventing economical implementation of Space Solar Power), has a number of quite reasonable solutions. Finally, it will consider whether Space Solar Power, along with the other major space goals of Science &Exploration, Mars Colonization, Non- terrestrial Materials Recovery and Space Tourism, could be another space "killer app" which, by creating a high demand for launch services, could force large reductions in launch costs.

  18. Generation and evaluation of space-Time trajectories of photovoltaic power

    DEFF Research Database (Denmark)

    Golestaneh, Faranak; Gooi, Hoay Beng; Pinson, Pierre


    In the probabilistic energy forecasting literature, emphasis is mainly placed on deriving marginal predictive densities for which each random variable is dealt with individually. Such marginals description is sufficient for power systems related operational problems if and only if optimal decisions...... are to be made for each lead-time and each location independently of each other. However, many of these operational processes are temporally and spatially coupled, while uncertainty in photovoltaic (PV) generation is strongly dependent in time and in space. This issue is addressed here by analysing and capturing...... spatio-temporal dependencies in PV generation. Multivariate predictive distributions are modelled and space-time trajectories describing the potential evolution of forecast errors through successive lead-times and locations are generated. Discrimination ability of the relevant scoring rules...

  19. Small Fish Species as Powerful Model Systems to Study Vertebrate Physiology in Space (United States)

    Muller, M.; Aceto, J.; Dalcq, J.; Alestrom, P.; Nourizadeh-Lillabadi, R.; Goerlich, R.; Schiller, V.; Winkler, C.; Renn, J.; Eberius, M.; Slenzka, K.


    Small fish models, mainly zebrafish (Danio rerio) and medaka (Oryzias latipes), have been used for many years as powerful model systems for vertebrate developmental biology. Moreover, these species are increasingly recognized as valuable systems to study vertebrate physiology, pathology, pharmacology and toxicology, including in particular bone physiology. The biology of small fishes presents many advantages, such as transparency of the embryos, external and rapid development, small size and easy reproduction. Further characteristics are particularly useful for space research or for large scale screening approaches. Finally, many technologies for easily characterizing bones are available. Our objective is to investigate the changes induced by microgravity in small fish. By combining whole genome analysis (microarray, DNA methylation, chromatin modification) with live imaging of selected genes in transgenic animals, a comprehensive and integrated characterization of physiological changes in space could be gained, especially concerning bone physiology.

  20. Super-Survey Tidal Effect on Redshift-space Power Spectrum

    CERN Document Server

    Akitsu, Kazuyuki; Li, Yin


    Long-wavelength matter inhomogeneities contain cleaner information on the nature of primordial perturbations as well as the physics of the early universe. The large-scale coherent overdensity and tidal force, not directly observable for a finite-volume galaxy survey, are both related to the Hessian matrix of large-scale gravitational potential and therefore of equal importance. We show that the coherent tidal force causes a homogeneous anisotropic distortion of the observed distribution of galaxies in all three directions, perpendicular and parallel to the line-of-sight direction. This effect mimics the redshift-space distortion signal of galaxy peculiar velocities, as well as a distortion by the Alcock-Paczynski effect. We quantify its impact on the redshift-space power spectrum to the leading order, and discuss its importance for the ongoing and upcoming galaxy surveys.

  1. A novel concentrator with zero-index metamaterial for space solar power station (United States)

    Huang, Jin; Chu, Xue-mei; Fan, Jian-yu; Jin, Qi-bao; Duan, Zhu-zhu


    Space solar power station (SSPS) is a comprehensive system that continuously collects solar energy in space and transmits it to ground with a wireless power transmission (WPT) system. These systems have great potential to provide large-scale energy. To increase the efficiency and reduce the weight and cost of the photovoltaic (PV) components, a huge light-weighted concentrator was introduced in the latest SSPS concepts, such as integrated symmetrical concentrator (ISC) and arbitrarily large phased array (ALPHA). However, for typical SSPS running in Geostationary Earth Orbit (GEO), the sunlight direction varies with time, leading to a great challenge for concentrator design. In ISC, the two-dimensional mast is used to realize sun-tracking. However, a multi-thousand-ton structure is difficult to control precisely in space. For this reason, ALPHA comprises a large number of individually pointed thin-film reflectors to intercept sunlight, mounted on the non-moving structure. However, the real-time adjustment of the thousands of reflectors is still an open problem. Furthermore, the uniformity of the time of the power generation (UTPG) is another factor evaluating the system. Therefore, this paper proposes a novel concentrator based on zero-index metamaterial (ZIM) called Thin-film Energy Terminator (SSPS-TENT). This will aid the control of the massive reflectors while avoiding the rotation of the overall system, the control of the massive reflectors and the influence of the obliquity of the ecliptic. Also, an optimization design method is proposed to increase its solar energy collecting efficiency (ECE) and flux distribution (FD). The ray-tracing simulation results show that the ECE is more than 96% of the day. In terms of the FD, the uniformity varies from 0.3057 to 0.5748. Compared with ALPHA, the UTPG is more stable.

  2. Thin-Film Solar Cells on Polymer Substrates for Space Power (United States)

    Hepps, A. F.; McNatt, Jeremiah; Morel, D. L.; Ferckides, C. S.; Jin, M. H.; Orbey, N.; Cushman, M.; Birkmire, R. W.; Shafarman, W. N.; Newton, R.


    Photovoltaic arrays have played a key role in power generation in space. The current technology will continue to evolve but is limited in the important mass specific power metric (MSP or power/weight ratio) because it is based on bulk crystal technology. Solar cells based on thin-film materials offer the promise of much higher MSP and much lower cost. However, for many space applications, a 20% or greater AM0 efficiency (eta) may be required. The leading thin-film materials, amorphous Si, CuInSe, and CdTe have seen significant advances in efficiency over the last decade but will not achieve the required efficiency in the near future. Several new technologies are herein described to maximize both device eta and MSP. We will discuss these technologies in the context of space exploration and commercialization. One novel approach involves the use of very lightweight polyimide substrates. We describe efforts to enable this advance including materials processing and device fabrication and characterization. Another approach involves stacking two cells on top of each other. These tandem devices more effectively utilize solar radiation by passing through non-absorbed longer wavelength light to a narrow-bandgap bottom cell material. Modeling of current devices in tandem format indicates that AM0 efficiencies near 20% can be achieved with potential for 25% in the near future. Several important technical issues need to be resolved to realize the benefits of lightweight technologies for solar arrays, such as: monolithic interconnects, lightweight array structures, and new ultra-light support and deployment mechanisms. Recent advances will be stressed.

  3. Investigations of Physical Processes in Microgravity Relevant to Space Electrochemical Power Systems (United States)

    Lvovich, Vadim F.; Green, Robert; Jakupca, Ian


    NASA has performed physical science microgravity flight experiments in the areas of combustion science, fluid physics, material science and fundamental physics research on the International Space Station (ISS) since 2001. The orbital conditions on the ISS provide an environment where gravity driven phenomena, such as buoyant convection, are nearly negligible. Gravity strongly affects fluid behavior by creating forces that drive motion, shape phase boundaries and compress gases. The need for a better understanding of fluid physics has created a vigorous, multidisciplinary research community whose ongoing vitality is marked by the continuous emergence of new fields in both basic and applied science. In particular, the low-gravity environment offers a unique opportunity for the study of fluid physics and transport phenomena that are very relevant to management of fluid - gas separations in fuel cell and electrolysis systems. Experiments conducted in space have yielded rich results. These results provided valuable insights into fundamental fluid and gas phase behavior that apply to space environments and could not be observed in Earth-based labs. As an example, recent capillary flow results have discovered both an unexpected sensitivity to symmetric geometries associated with fluid container shape, and identified key regime maps for design of corner or wedge-shaped passive gas-liquid phase separators. In this presentation we will also briefly review some of physical science related to flight experiments, such as boiling, that have applicability to electrochemical systems, along with ground-based (drop tower, low gravity aircraft) microgravity electrochemical research. These same buoyancy and interfacial phenomena effects will apply to electrochemical power and energy storage systems that perform two-phase separation, such as water-oxygen separation in life support electrolysis, and primary space power generation devices such as passive primary fuel cell.

  4. An out-of-core thermionic-converter system for nuclear space power. (United States)

    Breitwieser, R.


    Reexamination of designs of nuclear thermionic space power systems with the converter outside the reactor in the perspective of recent advances in heat-transfer methods, materials, converter performance, and radiation design. The 40- to 70-kW(e) power range is treated. The configuration is found to meet the constraints of readily available launch vehicles. It allows for off-design operation including startup, shutdown, and possible emergency conditions; provides tolerance of failure by extensive use of modular, redundant elements; incorporates and uses heat pipes in a fashion that reduces the need for extensive in-pile testing of system components; and uses thermionic converters, nuclear fuel elements, and heat-transfer devices in a geometrical form adapted from existing incore thermionic system designs.

  5. Frequency Domain Modeling and Simulation of DC Power Electronic Systems Using Harmonic State Space Method

    DEFF Research Database (Denmark)

    Kwon, Jun Bum; Wang, Xiongfei; Blaabjerg, Frede


    For the efficiency and simplicity of electric systems, the dc power electronic systems are widely used in a variety of applications such as electric vehicles, ships, aircraft and also in homes. In these systems, there could be a number of dynamic interactions and frequency coupling between network...... with different switching frequency or harmonics from ac-dc converters makes that harmonics and frequency coupling are both problems of ac system and challenges of dc system. This paper presents a modeling and simulation method for a large dc power electronic system by using Harmonic State Space (HSS) modeling...... and loads and other converters. Hence, time-domain simulations are usually required to consider such a complex system behavior. However, simulations in the time-domain may increase the calculation time and the utilization of computer memory. Furthermore, frequency coupling driven by multiple converters...

  6. An Iterative Power Allocation Algorithm for Group-wise Space-Time Block Coding Systems

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hong-wei; ZHANG Hai-bin; SONG Wen-tao; LUO Han-wen; LIU Xing-zhao


    An iterative transmit power allocation (PA) algorithm was proposed for group-wise space-time block coding (G-STBC) systems with group-wise successive interference cancellation (GSIC) receivers.Group-wise interference suppression (GIS) filters are employed to separate each group's transmit signals from other interfer ences and noise.While the total power on all transmit symbols is constrained, all transmit PA coefficients are updated jointly according to the channel information at each iteration.Through PA, each detection symbol has the same post-detection signal to interference-and-noise ratio (SINR).The simulation results verify that the proposed PA algorithm converges at the equilibrium quickly after few iterations, and it achieves much lower bit error rates than the previous single symbol SIC PA and the fixed ratio PA algorithms for G-STBC systems with GSIC receivers.

  7. High Conductivity Carbon-Carbon Heat Pipes for Light Weight Space Power System Radiators (United States)

    Juhasz, Albert J.


    Based on prior successful fabrication and demonstration testing of a carbon-carbon heat pipe radiator element with integral fins this paper examines the hypothetical extension of the technology via substitution of high thermal conductivity composites which would permit increasing fin length while still maintaining high fin effectiveness. As a result the specific radiator mass could approach an ultimate asymptotic minimum value near 1.0 kg/m2, which is less than one fourth the value of present day satellite radiators. The implied mass savings would be even greater for high capacity space and planetary surface power systems, which may require radiator areas ranging from hundreds to thousands of square meters, depending on system power level.

  8. Wireless ultra-wide-band transmission prototype ASICs for low-power space and radiation applications

    Energy Technology Data Exchange (ETDEWEB)

    Gabrielli, A. [Istituto Nazionale di Fisica Nucleare (INFN), Bologna (Italy); Department of Physics and Astronomy, University of Bologna, Bologna (Italy); Crepaldi, M. [IIT@Polito Istituto Italiano Tecnologia, Politecnico di Torino, Torino (Italy); Demarchi, D. [IIT@Polito Istituto Italiano Tecnologia, Politecnico di Torino, Torino (Italy); Department of Electronics (DELEN), Politecnico di Torino, Torino (Italy); Motto Ros, P. [IIT@Polito Istituto Italiano Tecnologia, Politecnico di Torino, Torino (Italy); Villani, G. [Science Technology Facility Council (STFC), Rutherford Appleton Laboratory (RAL), Didcot (United Kingdom)


    The paper describes the design and the fabrication of a microelectronic circuit composed of a sensor, an oscillator, a modulator, a transmitter and an antenna. The chip embeds a custom radiation sensor, provided by the silicon foundry that has fabricated the prototypes, but in principle the entire system can read a general sensor, as long as a proper interface circuit is used. The natural application for this circuit is radiation monitoring but the low-power budget extends the applications to space where wireless readout circuits can be applied to any type of sensors, even if not radiation sensitive devices.

  9. Electric space heating scheduling for real-time explicit power control in active distribution networks

    DEFF Research Database (Denmark)

    Costanzo, Giuseppe Tommaso; Bernstein, Andrey; Chamorro, Lorenzo Reyes


    This paper presents a systematic approach for abstracting the flexibility of a building space heating system and using it within a composable framework for real-time explicit power control of microgrids and, more in general, active distribution networks. In particular, the proposed approach...... is developed within the context of a previously defined microgrid control framework, called COMMELEC, conceived for the explicit and real-time control of these specific networks. The designed control algorithm is totally independent from the need of a building model and allows exploiting the intrinsic thermal...

  10. Development of Liquid-Vapor Core Reactors with MHD Generator for Space Power and Propulsion Applications

    Energy Technology Data Exchange (ETDEWEB)

    Samim Anghaie


    Any reactor that utilizes fuel consisting of a fissile material in a gaseous state may be referred to as a gaseous core reactor (GCR). Studies on GCRs have primarily been limited to the conceptual phase, mostly due to budget cuts and program cancellations in the early 1970's. A few scientific experiments have been conducted on candidate concepts, primarily of static pressure fissile gas filling a cylindrical or spherical cavity surrounded by a moderating shell, such as beryllium, heavy water, or graphite. The main interest in this area of nuclear power generation is for space applications. The interest in space applications has developed due to the promise of significant enhancement in fuel utilization, safety, plant efficiency, special high-performance features, load-following capabilities, power conversion optimization, and other key aspects of nuclear power generation. The design of a successful GCR adapted for use in space is complicated. The fissile material studied in the pa st has been in a fluorine compound, either a tetrafluoride or a hexafluoride. Both of these molecules have an impact on the structural material used in the making of a GCR. Uranium hexafluoride as a fuel allows for a lower operating temperature, but at temperatures greater than 900K becomes essentially impossible to contain. This difficulty with the use of UF6 has caused engineers and scientists to use uranium tetrafluoride, which is a more stable molecule but has the disadvantage of requiring significantly higher operating temperatures. Gas core reactors have traditionally been studied in a steady state configuration. In this manner a fissile gas and working fluid are introduced into the core, called a cavity, that is surrounded by a reflector constructed of materials such as Be or BeO. These reactors have often been described as cavity reactors because the density of the fissile gas is low and criticality is achieved only by means of the reflector to reduce neutron leakage from the

  11. A 90nm, Low Power VCO with Reduced KVCO and Sub−band Spacing Variation


    Collins, Diarmuid; Keady, Aidan; Szczepkowski, Grzegorz; Farrell, Ronan


    In this paper we present the design of a low power VCO with reduced variations in VCO gain (KVCO) and subband spacing resolution (fres). The proposed VCO is designed using a 90nm CMOS process to cover a tuning range of 23%. Variations in KVCO and fres are reduced by factors of 6 and 17 respectively over a conventional sub-banded VCO, designed using the same process, to meet the same tuning range. This makes the proposed VCO more suited to stable PLL operation with its ...

  12. High power, high efficiency millimeter wavelength traveling wave tubes for high rate communications from deep space (United States)

    Dayton, James A., Jr.


    The high-power transmitters needed for high data rate communications from deep space will require a new class of compact, high efficiency traveling wave tubes (TWT's). Many of the recent TWT developments in the microwave frequency range are generically applicable to mm wave devices, in particular much of the technology of computer aided design, cathodes, and multistage depressed collectors. However, because TWT dimensions scale approximately with wavelength, mm wave devices will be physically much smaller with inherently more stringent fabrication tolerances and sensitivity to thermal dissipation.

  13. Materials technology programs in support of a mercury Rankine space power system (United States)

    Stone, P. L.


    A large portion of the materials technology is summarized that was generated in support of the development of a mercury-rankine space power system (SNAP-8). The primary areas of investigation are: (1) the compatibility of various construction materials with the liquid metals mercury and NaK, (2) the mechanical properties of unalloyed tantalum, and (3) the development of refractory metal/austenitic stainless steel tubing and transition joints. The primary results, conclusions, and state of technology at the completion of this effort for each of these areas are summarized. Results of possible significance to other applications are highlighted.

  14. Materials technology for an advanced space power nuclear reactor concept: Program summary (United States)

    Gluyas, R. E.; Watson, G. K.


    The results of a materials technology program for a long-life (50,000 hr), high-temperature (950 C coolant outlet), lithium-cooled, nuclear space power reactor concept are reviewed and discussed. Fabrication methods and compatibility and property data were developed for candidate materials for fuel pins and, to a lesser extent, for potential control systems, reflectors, reactor vessel and piping, and other reactor structural materials. The effects of selected materials variables on fuel pin irradiation performance were determined. The most promising materials for fuel pins were found to be 85 percent dense uranium mononitride (UN) fuel clad with tungsten-lined T-111 (Ta-8W-2Hf).

  15. Scheme for Generation of Entanglement among Bimodal Cavities

    Institute of Scientific and Technical Information of China (English)

    SONG Xin-Guo; FENG Xun-Li


    @@ We present a scheme for generation of an entangled state in many spatially separated bimodal cavity modes via cavity quantum electrodynamics. A V-type three-level atom, initially prepared in a coherent superposition of its excited states, successively passes through both the bimodal cavities. If the atom is measured in its ground state after leaving the last cavity, an entangled state of many cavity modes can be generated. The conditions to generate the maximally entangled state with unity probability are worked out.

  16. Bimodal pattern in the fragmentation of Au quasi-projectiles

    CERN Document Server

    Bruno, M; D'Agostino, M; Gramegna, F; Gulminelli, F; Vannini, G


    Signals of bimodality have been investigated in experimental data of quasi-projectile decay produced in Au+Au collisions at 35 AMeV. This same data set was already shown to present several signals characteristic of a first order, liquid-gas-like phase transition. For the present analysis, events are sorted in bins of transverse energy of light charged particles emitted by the quasi-target source. A sudden change in the fragmentation pattern is observed from the distributions of the asymmetry of the two largest fragments, and the charge of the largest fragment. This latter distribution shows a bimodal behavior. The interpretation of this signal is discussed.

  17. An architecture for object-oriented intelligent control of power systems in space (United States)

    Holmquist, Sven G.; Jayaram, Prakash; Jansen, Ben H.


    A control system for autonomous distribution and control of electrical power during space missions is being developed. This system should free the astronauts from localizing faults and reconfiguring loads if problems with the power distribution and generation components occur. The control system uses an object-oriented simulation model of the power system and first principle knowledge to detect, identify, and isolate faults. Each power system component is represented as a separate object with knowledge of its normal behavior. The reasoning process takes place at three different levels of abstraction: the Physical Component Model (PCM) level, the Electrical Equivalent Model (EEM) level, and the Functional System Model (FSM) level, with the PCM the lowest level of abstraction and the FSM the highest. At the EEM level the power system components are reasoned about as their electrical equivalents, e.g, a resistive load is thought of as a resistor. However, at the PCM level detailed knowledge about the component's specific characteristics is taken into account. The FSM level models the system at the subsystem level, a level appropriate for reconfiguration and scheduling. The control system operates in two modes, a reactive and a proactive mode, simultaneously. In the reactive mode the control system receives measurement data from the power system and compares these values with values determined through simulation to detect the existence of a fault. The nature of the fault is then identified through a model-based reasoning process using mainly the EEM. Compound component models are constructed at the EEM level and used in the fault identification process. In the proactive mode the reasoning takes place at the PCM level. Individual components determine their future health status using a physical model and measured historical data. In case changes in the health status seem imminent the component warns the control system about its impending failure. The fault isolation

  18. Development of a power electronics unit for the Space Station plasma contactor (United States)

    Hamley, John A.; Hill, Gerald M.; Patterson, Michael J.; Saggio, Joseph, Jr.; Terdan, Fred; Mansell, Justin D.


    A hollow cathode plasma contactor has been baselined as a charge control device for the Space Station (SS) to prevent deleterious interactions of coated structural components with the ambient plasma. NASA LeRC Work Package 4 initiated the development of a plasma contactor system comprised of a Power Electronics Unit (PEU), an Expellant Management Unit (EMU), a command and data interface, and a Plasma Contactor Unit (PCU). A breadboard PEU was designed and fabricated. The breadboard PEU contains a cathode heater and discharge power supply, which were required to operate the PCU, a control and auxiliary power converter, an EMU interface, a command and telemetry interface, and a controller. The cathode heater and discharge supplies utilized a push-pull topology with a switching frequency of 20 kHz and pulse-width-modulated (PWM) control. A pulse ignition circuit derived from that used in arcjet power processors was incorporated in the discharge supply for discharge ignition. An 8088 based microcontroller was utilized in the breadboard model to provide a flexible platform for controller development with a simple command/data interface incorporating a direct connection to SS Mulitplexer/Demultiplexer (MDM) analog and digital I/O cards. Incorporating this in the flight model would eliminate the hardware and software overhead associated with a 1553 serial interface. The PEU autonomously operated the plasma contactor based on command inputs and was successfully integrated with a prototype plasma contactor unit demonstrating reliable ignition of the discharge and steady-state operation.

  19. High-Temperature Superconductive Cabling Investigated for Space Solar Power Satellites (United States)

    Tew, Roy C.; Juhasz, Albert J.


    NASA has been directed by Congress to take a fresh look at the Space Solar Power (SSP) concept that was studied by the Department of Energy and NASA about 20 years ago. To summarize, the concept involves (1) collecting solar energy and converting it to electrical energy via photovoltaic arrays on satellites in Earth orbit, (2) conducting the electricity to the microwave transmitting portion of the satellite, and (3) transmitting the power via microwave transmitters (or possibly via lasers) to ground power station antennas located on the surface of the Earth. One Sun Tower SSP satellite concept is illustrated here. This figure shows many photovoltaic arrays attached to a "backbone" that conducts electricity down to a wireless transmitter, which is pointed toward the Earth. Other variations on this concept use multiple backbones to reduce the overall length of the satellite structure. In addition, non-Sun-Tower concepts are being considered. The objective of the work reported here was to determine the benefits to the SSP concept of using high-temperature superconductors (HTS) to conduct the electricity from the photovoltaic arrays to the wireless power transmitters. Possible benefits are, for example, reduced mass, improved efficiency, and improved reliability. Dr. James Powell of Plus Ultra Technologies, Inc., of Stony Brook, New York, is conducting the study, and it is being managed by the NASA Glenn Research Center at Lewis Field via a task-order contract through Scientific Applications International Corp. (SAIC).

  20. Development of a Power Electronics Unit for the Space Station Plasma Contactor (United States)

    Hamley, John A.; Hill, Gerald M.; Patterson, Michael J.; Saggio, Joseph, Jr.; Terdan, Fred; Mansell, Justin D.


    A hollow cathode plasma contactor has been baselined as a charge control device for the Space Station (SS) to prevent deleterious interactions of coated structural components with the ambient plasma. NASA LeRC Work Package 4 initiated the development of a plasma contactor system comprised of a Power Electronics Unit (PEU), an Expellant Management Unit (EMU), a command and data interface, and a Plasma Contactor Unit (PCU). A breadboard PEU was designed and fabricated. The breadboard PEU contains a cathode heater and discharge power supply, which were required to operate the PCU, a control and auxiliary power converter, an EMU interface, a command and telemetry interface, and a controller. The cathode heater and discharge supplies utilized a push-pull topology with a switching frequency of 20 kHz and pulse-width-modulated (PWM) control. A pulse ignition circuit derived from that used in arcjet power processors was incorporated in the discharge supply for discharge ignition. An 8088 based microcontroller was utilized in the breadboard model to provide a flexible platform for controller development with a simple command/data interface incorporating a direct connection to SS Mulitplexer/Demultiplexer (MDM) analog and digital I/O cards. Incorporating this in the flight model would eliminate the hardware and software overhead associated with a 1553 serial interface. The PEU autonomously operated the plasma contactor based on command inputs and was successfully integrated with a prototype plasma contactor unit demonstrating reliable ignition of the discharge and steady-state operation.

  1. Nuclear reactor power for a space-based radar. SP-100 project (United States)

    Bloomfield, Harvey; Heller, Jack; Jaffe, Leonard; Beatty, Richard; Bhandari, Pradeep; Chow, Edwin; Deininger, William; Ewell, Richard; Fujita, Toshio; Grossman, Merlin


    A space-based radar mission and spacecraft, using a 300 kWe nuclear reactor power system, has been examined, with emphasis on aspects affecting the power system. The radar antenna is a horizontal planar array, 32 X 64 m. The orbit is at 61 deg, 1088 km. The mass of the antenna with support structure is 42,000 kg; of the nuclear reactor power system, 8,300 kg; of the whole spacecraft about 51,000 kg, necessitating multiple launches and orbital assembly. The assembly orbit is at 57 deg, 400 km, high enough to provide the orbital lifetime needed for orbital assembly. The selected scenario uses six Shuttle launches to bring the spacecraft and a Centaur G upper-stage vehicle to assembly orbit. After assembly, the Centaur places the spacecraft in operational orbit, where it is deployed on radio command, the power system started, and the spacecraft becomes operational. Electric propulsion is an alternative and allows deployment in assembly orbit, but introduces a question of nuclear safety.

  2. Feasibility study of a small, thorium-based fission power system for space and terrestrial applications (United States)

    Worrall, Michael Jason

    One of the current challenges facing space exploration is the creation of a power source capable of providing useful energy for the entire duration of a mission. Historically, radioisotope batteries have been used to provide load power, but this conventional system may not be capable of sustaining continuous power for longer duration missions. To remedy this, many forays into nuclear powered spacecraft have been investigated, but no robust system for long-term power generation has been found. In this study, a novel spin on the traditional fission power system that represents a potential optimum solution is presented. By utilizing mature High Temperature Gas Reactor (HTGR) technology in conjunction with the capabilities of the thorium fuel cycle, we have created a light-weight, long-term power source capable of a continuous electric power output of up to 70kW for over 15 years. This system relies upon a combination of fissile, highly-enriched uranium dioxide and fertile thorium carbide Tri-Structural Isotropic (TRISO) fuel particles embedded in a hexagonal beryllium oxide matrix. As the primary fissile material is consumed, the fertile material breeds new fissile material leading to more steady fuel loading over the lifetime of the core. Reactor control is achieved through an innovative approach to the conventional boron carbide neutron absorber by utilizing sections of borated aluminum placed in rotating control drums within the reflector. Borated aluminum allows for much smaller boron concentrations, thus eliminating the potential for 10B(n,alpha)6Li heating issues that are common in boron carbide systems. A wide range of other reactivity control systems are also investigated, such as a radially-split rotating reflector. Lastly, an extension of the design to a terrestrial based system is investigated. In this system, uranium enrichment is dropped to 20 percent in order to meet current regulations, a solid uranium-zirconium hydride fissile driver replaces the

  3. NASA's Space Launch System: Developing the World's Most Powerful Solid Booster (United States)

    Priskos, Alex


    NASA's Journey to Mars has begun. Indicative of that challenge, this will be a multi-decadal effort requiring the development of technology, operational capability, and experience. The first steps are under way with more than 15 years of continuous human operations aboard the International Space Station (ISS) and development of commercial cargo and crew transportation capabilities. NASA is making progress on the transportation required for deep space exploration - the Orion crew spacecraft and the Space Launch System (SLS) heavy-lift rocket that will launch Orion and large components such as in-space stages, habitat modules, landers, and other hardware necessary for deep-space operations. SLS is a key enabling capability and is designed to evolve with mission requirements. The initial configuration of SLS - Block 1 - will be capable of launching more than 70 metric tons (t) of payload into low Earth orbit, greater mass than any other launch vehicle in existence. By enhancing the propulsion elements and larger payload fairings, future SLS variants will launch 130 t into space, an unprecedented capability that simplifies hardware design and in-space operations, reduces travel times, and enhances the odds of mission success. SLS will be powered by four liquid fuel RS-25 engines and two solid propellant five-segment boosters, both based on space shuttle technologies. This paper will focus on development of the booster, which will provide more than 75 percent of total vehicle thrust at liftoff. Each booster is more than 17 stories tall, 3.6 meters (m) in diameter and weighs 725,000 kilograms (kg). While the SLS booster appears similar to the shuttle booster, it incorporates several changes. The additional propellant segment provides additional booster performance. Parachutes and other hardware associated with recovery operations have been deleted and the booster designated as expendable for affordability reasons. The new motor incorporates new avionics, new propellant

  4. Ultra High Power and Efficiency Space Traveling-Wave Tube Amplifier Power Combiner with Reduced Size and Mass for NASA Missions (United States)

    Simons, Rainee N.; Wintucky, Edwin G.; Wilson, Jeffrey D.; Force, Dale A.


    In the 2008 International Microwave Symposium (IMS) Digest version of our paper, recent advances in high power and efficiency space traveling-wave tube amplifiers (TWTAs) for NASA s space-to-Earth communications are presented. The RF power and efficiency of a new K-Band amplifier are 40 W and 50 percent and that of a new Ka-Band amplifier are 200 W and 60 percent. An important figure-of-merit, which is defined as the ratio of the RF power output to the mass (W/kg) of a TWT, has improved by a factor of ten over the previous generation Ka-Band devices. In this extended paper, a high power, high efficiency Ka-band combiner for multiple TWTs, based on a novel hybrid magic-T waveguide circuit design, is presented. The measured combiner efficiency is as high as 90 percent. In addition, at the design frequency of 32.05 GHz, error-free uncoded BPSK/QPSK data transmission at 8 megabits per second (Mbps), which is typical for deep space communications is demonstrated. Furthermore, QPSK data transmission at 622 Mbps is demonstrated with a low bit error rate of 2.4x10(exp -8), which exceeds the deep space state-of-the-art data rate transmission capability by more than two orders of magnitude. A potential application of the TWT combiner is in deep space communication systems for planetary exploration requiring transmitter power on the order of a kilowatt or higher.

  5. Space debris proximity analysis in powered and orbital phases during satelitte launch (United States)

    Bandyopadhyay, P.; Sharma, R.; Adimurthy, V.

    The need to protect a launch vehicle in its ascent phase as well as the payload upon injection in particular and to prevent generation of debris in general through collision has led to many recent developments in the methodologies of SPAce DEbris PROximity (SPADEPRO) analysis, which is required for COLlision Avoidance or COLA studies. SPADEPRO refers to assessment of collision risk between catalogued resident space objects and launch vehicle or satellite of interest. The detection of close approaches to satellites/launch vehicles during the launch and early post-deployment phase of their lifetimes is an important subset of the overall problem. Potential collisions during this period can usually be avoided by adjusting the time of launch within a specified launch window. In Ref- 1 a series of filters through which candidate objects have to pass before determining its close approach distances from either analytical propagators like SGP4/SDP4 or any numerical prediction package, has been described. Unfortunately, this detection technique cannot strictly be applied since assumption of orbital motion is violated when powered launch trajectories are considered. Ref- 2 has proposed an algorithm for determining launch window blackout intervals based on the avoidance of close approaches for trajectories, which are fixed relative to an Earth Centered Earth Fixed (ECEF) reference frame. In this paper, authors approximate the powered launch trajectory into a series of orbital trajectories so that those trajectories envelope the powered launch trajectory in position-velocity phase space. Following this, filters described in Ref- 1 have been utilized to find out potential candidates from resident space objects. In Ref- 2, 3 &4 the blackout period has been observed when the closest approach distance is below a certain threshold. Instead, in this paper authors use collision probability, considering dispersions in respective trajectories of resident space objects and launch vehicle

  6. Harmonic Instability Assessment Using State-Space Modeling and Participation Analysis in Inverter-Fed Power Systems

    DEFF Research Database (Denmark)

    Wang, Yanbo; Wang, Xiongfei; Blaabjerg, Frede


    This paper presents a harmonic instability analysis method using state-space modeling and participation analysis in the inverter-fed ac power systems. A full-order state-space model for the droop-controlled Distributed Generation (DG) inverter is built first, including the time delay of the digit...

  7. Technology demonstration of a free-piston stirling advanced radioisotope space power system (United States)

    White, Maurice A.; Qiu, Songgang; Olan, Ronald W.; Erbeznik, Raymond M.


    Free-piston Stirling convertors (Stirling engine with integral linear alternator) are a mature technology with demonstrated long-life, maintenance-free, degradation-free operation exceeding 46,000 hours (5+ years) on one unit. Tens of thousands of hours have been accumulated on numerous systems in beta trials, plus more than 8 million flexure-hours (900 flexure-years) on the most critical component (flexure bearings), all with no failures when operated within specifications. Vibration is a key concern for Stirling convertors in space. Recent tests have demonstrated a factor of 50 reduction in vibration, relative to a single convertor, by coupling two convertors mechanically and electrically. Even though the measured vibration level is below Jet Propulsion Laboratory (JPL) specified vibration objectives, demonstration of an additional factor of 10 vibration reduction is pending with an active vibration reduction system. Stirling cycle efficiency is well established. A four-convertor 150-W(e) end of mission (EOM) power system for deep space missions is projected to require only three general purpose heat source (GPHS) modules with conservative Inconel 718 heater heads, leaving significant efficiency improvement potential when used with higher temperature materials. Even in the unlikely scenario of one inoperative convertor, the other three convertors ramp up to provide full output. A two-convertor demonstration system, representative of one-half of a 150-W(e) power system, is described in this paper and scheduled to become operational in December 1998.

  8. Space Station Power Generation in Support of the Beta Gimbal Anomaly Resolution (United States)

    Delleur, Ann M.; Propp, Timothy W.


    The International Space Station (ISS) is the largest and most complex spacecraft ever assembled and operated in orbit. The first U.S. photovoltaic (PV) module, containing two solar arrays, was launched, installed, and activated in early December 2000. After the first week of continuously rotating the U.S. solar arrays, engineering personnel in the ISS Mission Evaluation Room (MER) observed higher than expected electrical currents on the drive motor in one of the Beta Gimbal Assemblies (BGA), the mechanism used to maneuver a U.S. solar array. The magnitude of the motor currents continued to increase over time on both BGA's, creating concerns about the ability of the gimbals to continue pointing the solar arrays towards the sun, a function critical for continued assembly of the ISS. A number of engineering disciplines convened in May 2001 to address this on-orbit hardware anomaly. This paper reviews the ISS electrical power system (EPS) analyses performed to develop viable operational workarounds that would minimize BGA use while maintaining sufficient solar array power to continue assembly of the ISS. Additionally, EPS analyses performed in support of on-orbit BGA troubleshooting exercises is reviewed. EPS capability analyses were performed using SPACE, a computer code developed by NASA Glenn Research Center (GRC) for the ISS program office.

  9. Galaxy power spectrum in redshift space: combining perturbation theory with the halo model

    CERN Document Server

    Okumura, Teppei; Seljak, Uros; Vlah, Zvonimir; Desjacques, Vincent


    Theoretical modeling of the redshift-space power spectrum of galaxies is crucially important to correctly extract cosmological information from redshift surveys. The task is complicated by the nonlinear biasing and redshift space distortion effects, which change with halo mass, and by the wide distribution of halo masses and their occupations by galaxies. One of the main modeling challenges is the existence of satellite galaxies that have both radial distribution and large virial velocities inside halos, a phenomenon known as the Finger-of-God effect. We present a model for the galaxy power spectrum of in which we decompose a given galaxy sample into central and satellite galaxies and relate different contributions to 1- and 2-halo terms in a halo model. Our primary goal is to ensure that any parameters that we introduce have physically meaningful values, and are not just fitting parameters. For the 2-halo terms we use the previously developed RSD modeling of halos in the context of distribution function and ...

  10. Distributed Space-Time Block Coded Transmission with Imperfect Channel Estimation: Achievable Rate and Power Allocation

    Directory of Open Access Journals (Sweden)

    Sonia Aïssa


    Full Text Available This paper investigates the effects of channel estimation error at the receiver on the achievable rate of distributed space-time block coded transmission. We consider that multiple transmitters cooperate to send the signal to the receiver and derive lower and upper bounds on the mutual information of distributed space-time block codes (D-STBCs when the channel gains and channel estimation error variances pertaining to different transmitter-receiver links are unequal. Then, assessing the gap between these two bounds, we provide a limiting value that upper bounds the latter at any input transmit powers, and also show that the gap is minimum if the receiver can estimate the channels of different transmitters with the same accuracy. We further investigate positioning the receiving node such that the mutual information bounds of D-STBCs and their robustness to the variations of the subchannel gains are maximum, as long as the summation of these gains is constant. Furthermore, we derive the optimum power transmission strategy to achieve the outage capacity lower bound of D-STBCs under arbitrary numbers of transmit and receive antennas, and provide closed-form expressions for this capacity metric. Numerical simulations are conducted to corroborate our analysis and quantify the effects of imperfect channel estimation.

  11. Reliability Analysis of a 3-Machine Power Station Using State Space Approach

    Directory of Open Access Journals (Sweden)

    WasiuAkande Ahmed


    Full Text Available With the advent of high-integrity fault-tolerant systems, the ability to account for repairs of partially failed (but still operational systems become increasingly important. This paper presents a systemic method of determining the reliability of a 3-machine electric power station, taking into consideration the failure rates and repair rates of the individual component (machine that make up the system. A state-space transition process for a 3-machine with 23 states was developed and consequently, steady state equations were generated based on Markov mathematical modeling of the power station. Important reliability components were deduced from this analysis. This research simulation was achieved with codes written in Excel® -VBA programming environment. System reliability using state space approach proofs to be a viable and efficient technique of reliability prediction as it is able to predict the state of the system under consideration. For the purpose of neatness and easy entry of data, Graphic User Interface (GUI was designed.

  12. MIC-Large Scale Magnetically Inflated Cable Structures for Space Power, Propulsion, Communications and Observational Applications (United States)

    Powell, James; Maise, George; Rather, John


    A new approach for the erection of rigid large scale structures in space-MIC (Magnetically Inflated Cable)-is described. MIC structures are launched as a compact payload of superconducting cables and attached tethers. After reaching orbit, the superconducting cables are energized with electrical current. The magnet force interactions between the cables cause them to expand outwards into the final large structure. Various structural shapes and applications are described. The MIC structure can be a simple flat disc with a superconducting outer ring that supports a tether network holding a solar cell array, or it can form a curved mirror surface that concentrates light and focuses it on a smaller region-for example, a high flux solar array that generates electric power, a high temperature receiver that heats H2 propellant for high Isp propulsion, and a giant primary reflector for a telescope for astronomy and Earth surveillance. Linear dipole and quadrupole MIC structures are also possible. The linear quadrupole structure can be used for magnetic shielding against cosmic radiation for astronauts, for example. MIC could use lightweight YBCO superconducting HTS (High Temperature Superconductor) cables, that can operate with liquid N2 coolant at engineering current densities of ~105 amp/cm2. A 1 kilometer length of MIC cable would weigh only 3 metric tons, including superconductor, thermal insulations, coolant circuits, and refrigerator, and fit within a 3 cubic meter compact package for launch. Four potential MIC applications are described: Solar-thermal propulsion using H2 propellant, space based solar power generation for beaming power to Earth, a large space telescope, and solar electric generation for a manned lunar base. The first 3 applications use large MIC solar concentrating mirrors, while the 4th application uses a surface based array of solar cells on a magnetically levitated MIC structure to follow the sun. MIC space based mirrors can be very large and light

  13. Space-time scenarios of wind power generation produced using a Gaussian copula with parametrized precision matrix

    DEFF Research Database (Denmark)

    Tastu, Julija; Pinson, Pierre; Madsen, Henrik

    The emphasis in this work is placed on generating space-time trajectories (also referred to as scenarios) of wind power generation. This calls for prediction of multivariate densities describing wind power generation at a number of distributed locations and for a number of successive lead times. ...

  14. A new state-space model for three-phase systems for Kalman filtering with application to power quality estimation (United States)

    Phan, Anh Tuan; Ho, Duc Du; Hermann, Gilles; Wira, Patrice


    For power quality issues like reducing harmonic pollution, reactive power and load unbalance, the estimation of the fundamental frequency of a power lines in a fast and precise way is essential. This paper introduces a new state-space model to be used with an extended Kalman filter (EKF) for estimating the frequency of distorted power system signals in real-time. The proposed model takes into account all the characteristics of a general three-phase power system and mainly the unbalance. Therefore, the symmetrical components of the power system, i.e., their amplitude and phase angle values, can also be deduced at each iteration from the proposed state-space model. The effectiveness of the method has been evaluated. Results and comparisons of online frequency estimation and symmetrical components identification show the efficiency of the proposed method for disturbed and time-varying signals.

  15. Bimodal versus Weibull wind speed distributions: an analysis of wind energy potential in La Venta, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Jaramillo, O.A.; Borja, M.A.


    The International Standard IEC 61400-12 and other international recommendations suggest the use of the two-parameter Weibull probability distribution function (PDF) to estimate the Annual Energy Production (AEP) of a wind turbine. Most of the commercial software uses the unimodal Weibull PDF as the default option to carry out estimations of AEP, which in turn, are used to optimise wind farm layouts. Furthermore, AEP is essential data to assess the economic feasibility of a wind power project. However, in some regions of the world, the use of these widely adopted and recommended methods lead to incorrect results. This is the case for the region of La Ventosa in Mexico, where the frequency of the wind speed shows a bimodal distribution. In this work, mathematical formulations by using a Weibull PDF and a bimodal distribution are established to compare the AEP, the capacity factor and the levelised production cost for a specific wind turbine. By combining one year of wind speed data with the hypothetic power performance of the Vestas V27-225 kW wind turbine, it was found that using the Weibull PDF underestimates AEP (and thus the Capacity Factor) by about 12%. (author)

  16. Space Solar Power Exploratory Research and Technology (SERT) Technical Interchange Meeting 2 (SERT TIM 2) (United States)

    Howell, Joe; Sanders, Clark W.


    The University of Alabama in Huntsville's (UAH) Propulsion Research Center hosted the Space Solar Power Exploratory Research & Technology (SERT) Technical Interchange Meeting TIM) 2 in Huntsville, Alabama December 7-10. 1999 with 126 people in attendance. The SERT program includes both competitively procured activities. which are being implemented through a portfolio of focused R&D investments--with the maximum leveraging of existing resources inside and outside NASA. and guided by these system studies. Axel Roth. Director of the Flight Projects Directorate NASA MSFC, welcomed the SERT TIM 2 participants and challenged them to develop the necessary technologies and demonstrations that will lead to Space Solar Power (SSP) International implementation. Joe Howell, NASA MSFC, reiterated the SERT TIM 2 objectives: 1) Refining and modeling systems approaches for the utilization of SSP concepts and technologies, ranging, from the near-term e.g. for space science, exploration and commercial space applications to the far-term (e. g. SSP for terrestrial markets), including systems concepts, technology, infrastructure (i.g., transportation), and economics. 2) Conducting technology research, development and demonstration activities to produce "proof- of-concept" validation of critical SSP elements for both the nearer and farther-term applications. 3) Initiating partnerships Nationality and Internationally that could be expanded, as appropriate, to pursue later SSP technology and applications (e.g., space science. colonization, etc.). Day one began with the NASA Centers presenting their SERT activities summary since SERT TIM 1 and wound up with a presentation by Masahiro Mori, NASDA titled "NASDA In-house Study for SSP". Demonstration for the Near-Term. Day two began with the SERT Systems Studies and Analysis reports resulting from NRA 8-23 followed by presentations of SERT Technology Demonstrations reports resulting from NRA 8-23. Day two closed with John Mankins presentation

  17. Bimodal behavior of the Kuroshio and the Gulf Stream

    NARCIS (Netherlands)

    Schmeits, M.J.; Dijkstra, H.A.


    For a long time, observations have been pointing out that the Kuroshio in the North Paciffc Ocean displays bimodal meandering behavior of the southern coast of Japan. For the Gulf Stream in the North Atlantic Ocean, weakly and strongly deffected paths near the coast of South Carolina have been obser

  18. On bimodality in warm season soil moisture observations

    NARCIS (Netherlands)

    Teuling, A.J.; Uijlenhoet, R.; Troch, P.A.A.


    It has recently been suggested that the bimodality in warm season soil moisture observations in Illinois is evidence of a soil moisture-precipitation feedback. Other studies however provide little evidence for a strong feedback in this region. Here we show that seasonality in the meteorological cond

  19. "Bi-modal" isoscalar giant dipole strength in Ni-58

    NARCIS (Netherlands)

    Nayak, B. K.; Garg, U.; Hedden, M.; Koss, M.; Li, T.; Liu, Y.; Rao, P. V. Madhusudhana; Zhu, S.; Itoh, M.; Sakaguchi, H.; Takeda, H.; Uchida, M.; Yasuda, Y.; Yosoi, M.; Fujimura, H.; Fujiwara, M.; Hara, K.; Kawabata, T.; Akimune, H.; Harakeh, M. N.


    The strength distribution of the isoscalar giant dipole resonance (ISGDR) in Ni-58 has been obtained over the energy range 10.5-49.5 MeV via extreme forward angle scattering (including 0 degrees) of 386 MeV alpha particles. We observe a "bi-modal" El strength distribution for the first time in an A

  20. A nonlinear theory of the bimodality of the Kuroshio extension

    NARCIS (Netherlands)

    Pierini, S.; Dijkstra, H.A.; Riccio, A.


    The Kuroshio Extension (KE) flow in the North Pacific Ocean displays a very distinctive decadal variability of bimodal character involving two completely different states (a large-meander “elongated” state and a small-meander “contracted” state) connected by very asymmetric temporal transitions. Alt

  1. Bimodal Bilingual Language Development of Hearing Children of Deaf Parents (United States)

    Hofmann, Kristin; Chilla, Solveig


    Adopting a bimodal bilingual language acquisition model, this qualitative case study is the first in Germany to investigate the spoken and sign language development of hearing children of deaf adults (codas). The spoken language competence of six codas within the age range of 3;10 to 6;4 is assessed by a series of standardised tests (SETK 3-5,…

  2. Visualisation and characterisation of heterogeneous bimodal PDMS networks

    DEFF Research Database (Denmark)

    Bahrt, Frederikke; Daugaard, Anders Egede; Fleury, Clemence;


    by rheology. All heterogeneous bimodal networks displayed significantly lower moduli than mono-modal PDMS elastomers prepared from the long polymer chains. Low-loss moduli as well as low-sol fractions indicate that low-elastic moduli can be obtained without compromising the network's structure...

  3. Does bimodal stimulus presentation increase ERP components usable in BCIs?

    NARCIS (Netherlands)

    Thurlings, M.E.; Brouwer, A.M.; Erp, J.B.F. van; Blankertz, B.; Werkhoven, P.J.


    Event-related potential (ERP)-based brain–computer interfaces (BCIs) employ differences in brain responses to attended and ignored stimuli. Typically, visual stimuli are used. Tactile stimuli have recently been suggested as a gaze-independent alternative. Bimodal stimuli could evoke additional brain

  4. Basic Research and Development Effort to Design a Micro Nuclear Power Plant for Brazilian Space Applications (United States)

    Guimares, L. N. F.; Camillo, G. P.; Placco, G. M.; Barrios, G., A., Jr.; Do Nascimento, J. A.; Borges, E. M.; De Castro Lobo, P. D.

    For some years the Nuclear Energy Division of the Institute for Advanced Studies is conducting the TERRA (Portuguese abbreviation for advanced fast reactor technology) project. This project aims at research and development of the key issues related with nuclear energy applied to space technology. The purpose of this development is to allow future Brazilian space explorers the access of a good and reliable heat, power and/or propulsion system based on nuclear energy. Efforts are being made in fuel and nuclear core design, designing and building a closed Brayton cycle loop for energy conversion, heat pipe systems research for passive space heat rejection, developing computational programs for thermal loop safety analysis and other technology that may be used to improve efficiency and operation. Currently there is no specific mission that requires these technology development efforts; therefore, there is a certain degree of freedom in the organization and development efforts. This paper will present what has been achieved so far, what is the current development status, where efforts are heading and a proposed time table to meet development objectives.

  5. Large Space Telescopes Using Fresnel Lens for Power Beaming, Astronomy and Sail Missions

    Energy Technology Data Exchange (ETDEWEB)

    Early, J T


    The concept of using Fresnel optics as part of power beaming, astronomy or sail systems has been suggested by several authors. The primary issues for large Fresnel optics are the difficulties in fabricating these structures and deploying them in space and for astronomy missions the extremely narrow frequency range of these optics. In proposals where the telescope is used to transmit narrow frequency laser power, the narrow bandwidth has not been an issue. In applications where the optic is to be used as part of a telescope, only around 10{sup -5} to limited frequency response of a Fresnel optic is addressed by the use of a corrective optic that will broaden the frequency response of the telescope by three or four orders of magnitude. This broadening will dramatically increase the optical power capabilities of the system and will allow some spectroscopy studies over a limited range. Both the fabrication of Fresnel optics as large as five meters and the use of corrector optics for telescopes have been demonstrated at LLNL. For solar and laser sail missions the use of Fresnel amplitude zone plates made of very thin sail material is also discussed.


    Energy Technology Data Exchange (ETDEWEB)

    J. C. Giglio; A. A. Jackson


    The Idaho National Laboratory (INL) is preparing to fuel and test the Advanced Stirling Radioisotope Generator (ASRG), the next generation space power generator. The INL identified the thermal vacuum test chamber used to test past generators as inadequate. A second vacuum chamber was upgraded with a thermal shroud to process the unique needs and to test the full power capability of the new generator. The thermal vacuum test chamber is the first of its kind capable of testing a fueled power system to temperature that accurately simulate space. This paper outlines the new test and set up capabilities at the INL.

  7. High Power and Efficiency Space Traveling-Wave Tube Amplifiers With Reduced Size and Mass for NASA Missions (United States)

    Simons, Rainee N.; Wilson, Jeffrey D.; Force, Dale A.


    Recent advances in high power and efficiency space traveling-wave tube amplifiers (TWTAs) for NASA s space-to-Earth communications are presented in this paper. The RF power and efficiency of a new K-Band amplifier are 40 W and 50 percent and that of a new Ka-Band amplifier are 200 W and 60 percent. An important figure-of-merit, which is defined as the ratio of the RF power output to the mass (W/kg) of a TWT has improved by a factor of ten over the previous generation Ka-Band devices.

  8. The bimodality of the Luzon Strait deep water

    Institute of Scientific and Technical Information of China (English)

    WU Qingsong; ZHAO Jianru; ZHANG Junbiao; SHI Weiyong; LIU Chunqiu


    Combined conductivity-temperature-depth (CTD) casts and Argo profiles, 3 086 historical hydrocasts were used to quantify the water column characteristics in the northern South China Sea (SCS) and its adjacent waters. Based on a two-dimensional“gravest empirical mode”(GEM), a gravitational potential (׋, a verti-cally integrated variable) was used as proxy for the vertical temperature profiles TG(p,׋).׋integrated from 8 MPa to the surface shows a close relationship with the temperature, except in the deep layer greater than 15 MPa, which was caused by the bimodal deep water in the region. The GEM temperature profiles successfully revealed the bimodality of the Luzon Strait deep water, that disparate hydrophic vertical profiles can pro-duce distinct specific volume anomaly (į) in the SCS and the western Philippine Sea (WPS), but failed in the Luzon Strait, where different temperature profiles may produce a sameį. A significant temperature diver-gence between the SCS water and the WPS water confirmed that the bimodal structure is strong. The deep-water bifurcation starts at about 15 MPa, and gets stronger with increasing depth . As the only deep channel connecting the bimodal-structure waters, water column characteristics in the Luzon Strait is in between, but much closer to the SCS water because of its better connectivity with the SCS. A bimodal temperature structure below 15 MPa reveals that there was a persistent baroclinic pressure gradient driving flow through the Luzon Strait. A volume flux predicted through the Bashi Channel with the hydraulic theory yields a value of 5.62×106 m3/s using all available profiles upstream and downstream of the overflow region, and 4.03×106 and 2.70×106 m3/s by exclusively using the profiles collected during spring and summer, respectively. No volume flux was calculated during autumn and winter because profiles are only available for the upstream of the Bashi Channel during the corresponding period.

  9. A Hypothesis for the Color Bimodality of Jupiter Trojans (United States)

    Wong, Ian; Brown, Michael E.


    One of the most enigmatic and hitherto unexplained properties of Jupiter Trojans is their bimodal color distribution. This bimodality is indicative of two sub-populations within the Trojans, which have distinct size distributions. In this paper, we present a simple, plausible hypothesis for the origin and evolution of the two Trojan color sub-populations. In the framework of dynamical instability models of early solar system evolution, which suggest a common primordial progenitor population for both Trojans and Kuiper Belt objects, we use observational constraints to assert that the color bimodalities evident in both minor body populations developed within the primordial population prior to the onset of instability. We show that, beginning with an initial composition of rock and ices, location-dependent volatile loss through sublimation in this primordial population could have led to sharp changes in the surface composition with heliocentric distance. We propose that the depletion or retention of H2S ice on the surface of these objects was the key factor in creating an initial color bimodality. Objects that retained H2S on their surfaces developed characteristically redder colors upon irradiation than those that did not. After the bodies from the primordial population were scattered and emplaced into their current positions, they preserved this primordial color bimodality to the present day. We explore predictions of the volatile loss model—in particular, the effect of collisions within the Trojan population on the size distributions of the two sub-populations—and propose further experimental and observational tests of our hypothesis.

  10. Advanced development and using of space nuclear power systems as a part of transport power supply modules for general purpose spacecraft (United States)

    Menshikov, Valery A.; Kuzin, Anatoly I.; Pavlov, Konstantin A.; Zatserkovny, Sergey P.; Kalmykov, Alexandr V.; Sorokin, Alexandr N.; Bulavatsky, Andrey Y.; Vasilkovsky, Vladimir V.; Zrodnikov, Anatoly V.; Trukhanov, Yuri L.; Nikolaev, Yuri V.; Bezzubtsev, Valery S.; Lutov, Evgeny I.; Pavshoock, Vladimir A.; Akimov, Vladimir N.; Arkhangelsky, Nicolay I.; Gladyshev, Sergey N.


    Nuclear transport power systems (NTPS) can provide solving such important science, commerce and defense tasks in space as radar surveillance, information affording, global ecological monitoring, defense of Earth from dangerous space objects, manufacturing in space, investigations of asteroids, comets and solar systems' planets (Kuzin et al. 1993a, 1993b). The creation of NTPS for real space systems, however, must be based on proved NTPS effectiveness in comparison with other power and propulsion systems such as, nonnuclear electric-rocket systems and so on. When the NTPS effectiveness is proved, the operation safety of such systems must be suited to the UN requirements for all stages of the life cycle in view of possible failures. A nuclear transport power module provides both a large amount of thermal and electrical power and a long acting time (about 6-7 years after completing the delivery task). For this reason such module is featured with the high power supplying-mass delivery effectiveness and the considerable increasing of the total effectiveness of a spacecraft with the module. In the report, the such NTPS three types, namely the system on the base of thermionic reactor-converter with electric rocket propulsion system (ERPS), the dual mode thermionic nuclear power system with pumping of working fluid through the active reactor zone, and the system on the base of the nuclear thermal rocket engine technology is compared with the transport power modules on the base of solar power system from the point of view of providing the highest degree of the effectiveness.

  11. Advanced development and using of space nuclear power systems as a part of transport power supply modules for general purpose spacecraft

    Energy Technology Data Exchange (ETDEWEB)

    Menshikov, V.A.; Kuzin, A.I.; Pavlov, K.A.; Zatserkovny, S.P. [Russian Federation Ministry of Defense Central, Scientific-Research Institute of Space Force, Moscow, K-160 (Russian Federation); Kalmykov, A.V.; Sorokin, A.N.; Bulavatsky, A.Y. [Russian Federation Ministry of Defense, Main Department of Space Force, Moscow, K-160 (Russian Federation); Vasilkovsky, V.V. [Russian Federation Ministry of Atomic Power, 26, Staromonetny St., Moscow, 101000 (Russia); Zrodnikov, A.V. [Russian Federation State Research Center, ``Institute of Physics and Power Engineering``, 1, Bondarenko Sq., Obninsk, Kaluga Region, 249020 (Russian Federation); Trukhanov, Y.L. [``Red Star`` State Enterprise, 1A, Electrolitny St., Moscow, 115230 (Russia); Nikolaev, Y.V. [Scientific Industrial Association ``Lutch``, 24, Zhelesnodorozhnaya St., Podolsk, Moscow Region, 142100 (Russia); Bezzubtsev, V.S. [Research and Development Institute of Power Engineering, Moscow, 101000 (Russia); Lutov, E.I. [Central Design Bureau for Machine Building, St. Petersburg, 195027 (Russia); Pavshoock, V.A. [Russian Research Center ``Kurchatov Institute``, 1, Kurchatov Sq., Moscow, 123182 (Russia); Akimov, V.N.; Arkhangelsky, N.I. [Scientific-Research Institute of Thermal Processes, 8/10, Onezhskaya St., Moscow, 125438 (Russia); Gladyshev, S.N. [State Rocket Center ``Design Bureau of Academician V.P. Makeev``, 1, Turgoyarskoe St., Miass, Tchelyabinsk Region, 456300 (Russia)


    Nuclear transport power systems (NTPS) can provide solving such important science, commerce and defense tasks in space as radar surveillance, information affording, global ecological monitoring, defense of Earth from dangerous space objects, manufacturing in space, investigations of asteroids, comets and solar systems{close_quote} planets (Kuzin {ital et} {ital al}. 1993a, 1993b). The creation of NTPS for real space systems, however, must be based on proved NTPS effectiveness in comparison with other power and propulsion systems such as, nonnuclear electric-rocket systems and so on. When the NTPS effectiveness is proved, the operation safety of such systems must be suited to the UN requirements for all stages of the life cycle in view of possible failures. A nuclear transport power module provides both a large amount of thermal and electrical power and a long acting time (about 6{endash}7 years after completing the delivery task). For this reason such module is featured with the high power supplying-mass delivery effectiveness and the considerable increasing of the total effectiveness of a spacecraft with the module. In the report, the such NTPS three types, namely the system on the base of thermionic reactor-converter with electric rocket propulsion system (ERPS), the dual mode thermionic nuclear power system with pumping of working fluid through the active reactor zone, and the system on the base of the nuclear thermal rocket engine technology is compared with the transport power modules on the base of solar power system from the point of view of providing the highest degree of the effectiveness. {copyright} {ital 1996 American Institute of Physics.}

  12. Performance Testing of a Liquid Metal Pump for In-Space Power Systems (United States)

    Polzin, Kurt


    Fission surface power (FSP) systems could be used to provide power on the surface of the moon, Mars, or other planets and moons of our solar system. Fission power systems could provide excellent performance at any location, including those near the poles or other permanently shaded regions, and offer the capability to provide on demand power at any time, even at large distances from the sun. Fission-based systems also offer the potential for outposts, crew and science instruments to operate in a power-rich environment. NASA has been exploring technologies with the goal of reducing the cost and technical risk of employing FSP systems. A reference 40 kWe option has been devised that is cost-competitive with alternatives while providing more power for less mass anywhere on the lunar surface. The reference FSP system is also readily extensible for use on Mars, where it would be capable of operating through global dust storms and providing year-round power at any Martian latitude. Detailed development of the FSP concept and the reference mission are documented in various other reports. The development discussed in this paper prepares the way for testing of the Technology Demonstration Unit (TDU), which is a 10 kWe end-to-end test of FSP technologies intended to raise the entire FSP system to technology readiness level (TRL) 6. The Early Flight Fission Test Facility (EFF-TF) was established by NASA s Marshall Space Flight Center (MSFC) to provide a capability for performing hardware-directed activities to support multiple in-space nuclear reactor concepts by using a nonnuclear test methodology. This includes fabrication and testing at both the module/component level and at near prototypic reactor components and configurations allowing for realistic thermal-hydraulic evaluations of systems. The liquid-metal pump associated with the FSP system must be compatible with the liquid NaK coolant and have adequate performance to enable a viable flight system. Idaho National

  13. The Promise and the Challenge of Space Solar Power in the 21st Century: Picking up the Gauntlet (United States)

    Mankins, John C.


    The history of human civilization is a history of great infrastructure. Chief among these developments have been advances in power, transport, and communications. Without dramatic and steady advances in these critical systems during the past two hundred years-- especially in the available sources of power--the world would be a drastically poorer and harsher home for humanity. At the same time, through the global use of existing energy technologies humanity is rapidly consuming irreplaceable fossil resources as well as changing the environment and the climate for the world itself. Both must raise concerns about the long-term sustainability of the infrastructures that have enabled our world. The importance of abundant and affordable energy in space exploration and development is equally clear. Current missions of exploration and scientific discovery are narrowly constrained by a lack of energy. Future, even more ambitious missions will never be realized without new, reliable and less expensive sources of energy. Even more, the potential emergence of new space industries such as space tourism, manufacturing in space, solar power satellites (SPS) and others, will depend on advances in space power systems just as much as they will on progress in space transportation. Recent studies and technological advances suggest that large-scale space solar power (SSP) systems may enable progress in both arenas during the next several decades. Of course, there are tremendous engineering and technological barriers that must be surmounted to someday make large SSP systems possible. Diverse areas of technology must be advanced. Some of these include space transportation, solar power generation, wireless power transmission, robotics, structural concepts and materials, and others. Nevertheless, there are potential benefits in the offing that seem to many to make challenging even these daunting technical barriers worthwhile--and perhaps essential. Unfortunately, the political and

  14. Space nuclear power systems; Proceedings of the 8th Symposium, Albuquerque, NM, Jan. 6-10, 1991. Pts. 1-3 (United States)

    El-Genk, Mohamed S. (Editor); Hoover, Mark D. (Editor)


    The present conference discusses NASA mission planning for space nuclear power, lunar mission design based on nuclear thermal rockets, inertial-electrostatic confinement fusion for space power, nuclear risk analysis of the Ulysses mission, the role of the interface in refractory metal alloy composites, an advanced thermionic reactor systems design code, and space high power nuclear-pumped lasers. Also discussed are exploration mission enhancements with power-beaming, power requirement estimates for a nuclear-powered manned Mars rover, SP-100 reactor design, safety, and testing, materials compatibility issues for fabric composite radiators, application of the enabler to nuclear electric propulsion, orbit-transfer with TOPAZ-type power sources, the thermoelectric properties of alloys, ruthenium silicide as a promising thermoelectric material, and innovative space-saving device for high-temperature piping systems. The second volume of this conference discusses engine concepts for nuclear electric propulsion, nuclear technologies for human exploration of the solar system, dynamic energy conversion, direct nuclear propulsion, thermionic conversion technology, reactor and power system control, thermal management, thermionic research, effects of radiation on electronics, heat-pipe technology, radioisotope power systems, and nuclear fuels for power reactors. The third volume discusses space power electronics, space nuclear fuels for propulsion reactors, power systems concepts, space power electronics systems, the use of artificial intelligence in space, flight qualifications and testing, microgravity two-phase flow, reactor manufacturing and processing, and space and environmental effects.

  15. High-Power, High-Efficiency Ka-Band Space Traveling-Wave Tube (United States)

    Krawczyk, Richard; Wilson, Jeffrey; Simons, Rainee; Williams, Wallace; Bhasin, Kul; Robbins, Neal; Dibb, Daniel; Menninger, William; Zhai, Xiaoling; Benton, Robert; Burdette, James


    The L-3 Communications Model 999H traveling-wave tube (TWT) has been demonstrated to generate an output power of 144 W at 60-percent overall efficiency in continuous-wave operation over the frequency band from 31.8 to 32.3 GHz. The best TWT heretofore commercially available for operation in the affected frequency band is characterized by an output power of only 35 W and an efficiency of 50 percent. Moreover, whereas prior TWTs are limited to single output power levels, it has been shown that the output power of the Model 999H can be varied from 54 to 144 W. A TWT is a vacuum electronic device used to amplify microwave signals. TWTs are typically used in free-space communication systems because they are capable of operating at power and efficiency levels significantly higher than those of solid-state devices. In a TWT, an electron beam is generated by an electron gun consisting of a cathode, focusing electrodes, and an anode. The electrons pass through a hole in the anode and are focused into a cylindrical beam by a stack of periodic permanent magnets and travel along the axis of an electrically conductive helix, along which propagates an electromagnetic wave that has been launched by an input signal that is to be amplified. The beam travels within the helix at a velocity close to the phase velocity of the electromagnetic wave. The electromagnetic field decelerates some of the electrons and accelerates others, causing the beam to become formed into electron bunches, which further interact with the electromagnetic wave in such a manner as to surrender kinetic energy to the wave, thereby amplifying the wave. The net result is to amplify the input signal by a factor of about 100,000. After the electrons have passed along the helix, they impinge on electrodes in a collector. The collector decelerates the electrons in such a manner as to recover most of the remaining kinetic energy and thereby significantly increase the power efficiency of the TWT.

  16. Characterising rock fracture aperture-spacing relationships using power-law relationships: some considerations (United States)

    Brook, Martin; Hebblewhite, Bruce; Mitra, Rudrajit


    The size-scaling of rock fractures is a well-studied problem in geology, especially for permeability quantification. The intensity of fractures may control the economic exploitation of fractured reservoirs because fracture intensity describes the abundance of fractures potentially available for fluid flow. Moreover, in geotechnical engineering, fractures are important for parameterisation of stress models and excavation design. As fracture data is often collected from widely-spaced boreholes where core recovery is often incomplete, accurate interpretation and representation of fracture aperture-frequency relationships from sparse datasets is important. Fracture intensity is the number of fractures encountered per unit length along a sample scanline oriented perpendicular to the fractures in a set. Cumulative frequency of fractures (F) is commonly related to fracture aperture (A) in the form of a power-law (F = aA-b), with variations in the size of the a coefficient between sites interpreted to equate to fracture frequency for a given aperture (A). However, a common flaw in this approach is that even a small change in b can have a large effect on the response of the fracture frequency (F) parameter. We compare fracture data from the Late Permian Rangal Coal Measures from Australia's Bowen Basin, with fracture data from Jurassic carbonates from the Sierra Madre Oriental, northeastern Mexico. Both power-law coefficient a and exponent b control the fracture aperture-frequency relationship in conjunction with each other; that is, power-laws with relatively low a coefficients have relatively high b exponents and vice versa. Hence, any comparison of different power-laws must take both a and b into consideration. The corollary is that different sedimentary beds in the Sierra Madre carbonates do not show ˜8× the fracture frequency for a given fracture aperture, as based solely on the comparison of coefficient a. Rather, power-law "sensitivity factors" developed from both

  17. Tolerance and Nature of Residual Refraction in Symmetric Power Space as Principal Lens Powers and Meridians Change


    Herven Abelman; Shirley Abelman


    Unacceptable principal powers in well-centred lenses may require a toric over-refraction which differs in nature from the one where correct powers have misplaced meridians. This paper calculates residual (over) refractions and their natures. The magnitude of the power of the over-refraction serves as a general, reliable, real scalar criterion for acceptance or tolerance of lenses whose surface relative curvatures change or whose meridians are rotated and cause powers to differ. Principal powe...

  18. Classification of power quality combined disturbances based on phase space reconstruction and support vector machines

    Institute of Scientific and Technical Information of China (English)


    Power Quality (PQ) combined disturbances become common along with ubiquity of voltage flickers and harmonics. This paper presents a novel approach to classify the different patterns of PQ combined disturbances. The classification system consists of two parts, namely the feature extraction and the automatic recognition. In the feature extraction stage, Phase Space Reconstruction (PSR), a time series analysis tool, is utilized to construct disturbance signal trajectories. For these trajectories, several indices are proposed to form the feature vectors. Support Vector Machines (SVMs) are then implemented to recognize the different patterns and to evaluate the efficiencies. The types of disturbances discussed include a combination of short-term disturbances (voltage sags, swells) and long-term disturbances (flickers, harmonics), as well as their homologous single ones. The feasibilities of the proposed approach are verified by simulation with thousands of PQ events. Comparison studies based on Wavelet Transform (WT) and Artificial Neural Network (ANN) are also reported to show its advantages.

  19. Survey of electronics capability for SP-100 space reactor power system applications (United States)

    Manvi, Ram; Fujita, Tosh


    Because of reports indicating improvements in the radiation tolerance of some electronic parts, a survey was recently performed by SP-100 project personnel to determine the advisability of revising SP-100 SRPS (space reactor power systems) allowable neutron and gamma dose rates in order to reduce the size and mass of the radiation shield and thereby achieve system mass reductions. The survey results indicate that recent developments to increase the radiation tolerance of a limited set of electronics parts do not justify increasing the allowable SP-100 dose rates for electronic components. Specifically, the recent improvements on a limited set of parts do not justify increasing the current SP-100 allowable specifications of 5 x 10 exp 5 rads gamma dose and 1 x 10 exp 13 neutrons/sq cm fluence. However, if the improvements of 108 rads for gammas and 10 exp 15 neutrons/sq cm can be extended to a wide range of parts, significant mass savings would result.

  20. Design of a Mechanical NaK Pump for Fission Space Power (United States)

    Mireles, Omar R.; Bradley, David E.; Godfroy, Thomas


    Alkali liquid metal cooled fission reactor concepts are under development for spaceflight power requirements. One such concept utilizes a sodium-potassium eutectic (NaK) as the primary loop working fluid, which has specific pumping requirements. Traditionally, electromagnetic linear induction pumps have been used to provide the required flow and pressure head conditions for NaK systems but they can be limited in performance, efficiency, and number of available vendors. The objective of the project was to develop a mechanical NaK centrifugal pump that takes advantages of technology advances not available in previous liquid metal mechanical pump designs. This paper details the design, build, and performance test of a mechanical NaK pump developed at NASA Marshall Space Flight Center. The pump was designed to meet reactor cooling requirements using commercially available components modified for high temperature NaK service.

  1. Mast material test program (MAMATEP). [for Solar Array Assembly of Space Station Photovoltaic Power Module (United States)

    Ciancone, Michael L.; Rutledge, Sharon K.


    The MAMATEP program, which is aimed at verifying the need for and evaluating the performance of various protection techniques for the solar array assembly mast of the Space Station photovoltaic power module, is discussed. Coated and uncoated mast material samples have been environmentally tested and evaluated, before and after testing, in terms of mass and bending modulus. The protective coatings include CV-1144 silicone, a Ni/Al/InSn eutectic, and an open-weave Al braid. Long-term plasma asher results from unprotected samples indicate that, even though fiberglass-epoxy samples degrade, a protection technique may not be necessary to ensure structural integrity. A protection technique, however, may be desirable to limit or contain the amount of debris generated by the degradation of the fiberglass-epoxy.

  2. The application of high temperature superconductors to space electrical power distribution components (United States)

    Aron, Paul R.; Myers, Ira T.


    Some important space based electrical power distribution systems and components are examined to determine what might be achieved with the introduction of high temperature superconductors (HTS). Components that are compared in a before-and-after fashion include transformers, transmission lines, and capacitors. It is concluded that HTS has its greatest effect on the weight associated with transmission lines, where the weight penalty could be reduced by as much as 130 kg/kW/km of cable. Transformers, because 28 percent of their mass is in the conductor, are reduced in weight by the same factor. Capacitors are helped the least with only negligible savings possible. Finally, because HTS can relax the requirement to use alternating current in order to reduce conductor mass, it will be possible to generate significant savings by eliminating most transformers and capacitors.

  3. Space charge dosimeters for extremely low power measurements of radiation in shipping containers (United States)

    Britton, Jr.; Charles L.; Buckner, Mark A.; Hanson, Gregory R.; Bryan, William L.


    Methods and apparatus are described for space charge dosimeters for extremely low power measurements of radiation in shipping containers. A method includes in situ polling a suite of passive integrating ionizing radiation sensors including reading-out dosimetric data from a first passive integrating ionizing radiation sensor and a second passive integrating ionizing radiation sensor, where the first passive integrating ionizing radiation sensor and the second passive integrating ionizing radiation sensor remain situated where the dosimetric data was integrated while reading-out. Another method includes arranging a plurality of ionizing radiation sensors in a spatially dispersed array; determining a relative position of each of the plurality of ionizing radiation sensors to define a volume of interest; collecting ionizing radiation data from at least a subset of the plurality of ionizing radiation sensors; and triggering an alarm condition when a dose level of an ionizing radiation source is calculated to exceed a threshold.

  4. Thin-film Organic-based Solar Cells for Space Power (United States)

    Bailey, Sheila G.; Harris, Jerry D.; Hepp, Aloysius F.; Anglin, Emily J.; Raffaelle, Ryne P.; Clark, Harry R., Jr.; Gardner, Susan T. P.; Sun, Sam S.


    Recent advances in dye-sensitized and organic polymer solar cells have lead NASA to investigate the potential of these devices for space power generation. Dye-sensitized solar cells were exposed to simulated low-earth orbit conditions and their performance evaluated. All cells were characterized under simulated air mass zero (AM0) illumination. Complete cells were exposed to pressures less than 1 x 10(exp -7) torr for over a month, with no sign of sealant failure or electrolyte leakage. Cells from Solaronix SA were rapid thermal cycled under simulated low-earth orbit conditions. The cells were cycled 100 times from -80 C to 80 C, which is equivalent to 6 days in orbit. The best cell had a 4.6 percent loss in efficiency as a result of the thermal cycling. In a separate project, novel -Bridge-Donor-Bridge- Acceptor- (-BDBA-) type conjugated block copolymer systems have been synthesized and characterized by photoluminescence (PL). In comparison to pristine donor or acceptor, the PL emissions of final -B-D-B-A- block copolymer films were quenched over 99 percent. Effective and efficient photo induced electron transfer and charge separation occurs due to the interfaces of micro phase separated donor and acceptor blocks. The system is very promising for a variety high efficiency light harvesting applications. Under an SBIR contract, fullerene-doped polymer-based photovoltaic devices were fabricated and characterized. The best devices showed overall power efficiencies of approx. 0.14 percent under white light. Devices fabricated from 2 percent solids content solutions in chlorobenzene gave the best results. Presently, device lifetimes are too short to be practical for space applications.

  5. Investigation of heat exchangers for energy conversion systems of megawatt-class space power plants (United States)

    Ilmov, D. N.; Mamontov, Yu. N.; Skorohodov, A. S.; Smolyarov, V. A.; Filatov, N. I.


    The specifics of operation (high temperatures in excess of 1000 K and large pressure drops of several megapascals between "hot" and "cold" coolant paths) of heat exchangers in the closed circuit of a gasturbine power converter operating in accordance with the Brayton cycle with internal heat recovery are analyzed in the context of construction of space propulsion systems. The design of a heat-exchange matrix made from doubly convex stamped plates with a specific surface relief is proposed. This design offers the opportunity to construct heat exchangers with the required parameters (strength, rigidity, weight, and dimensions) for the given operating conditions. The diagram of the working area of a test bench is presented, and the experimental techniques are outlined. The results of experimental studies of heat exchange and flow regimes in the models of heat exchangers with matrices containing 50 and 300 plates for two pairs of coolants (gas-gas and gas-liquid) are detailed. A criterion equation for the Nusselt number in the range of Reynolds numbers from 200 to 20 000 is proposed. The coefficients of hydraulic resistance for each coolant path are determined as functions of the Reynolds number. It is noted that the pressure in the water path in the "gas-liquid" series of experiments remained almost constant. This suggests that no well-developed processes of vaporization occurred within this heat-exchange matrix design even when the temperature drop between gas and water was as large as tens or hundreds of degrees. The obtained results allow one to design flight heat exchangers for various space power plants.

  6. Research on design feasibility of high-power light-weight dc-to-dc converters for space power applications (United States)

    Wilson, T. G.


    Utilizing knowledge gained from past experience with experimental current-or-voltage step-up dc-to-dc converter power stages operating at output powers up to and in excess of 2 kW, a new experimental current-or-voltage step-up power stage using paralleled bipolar junction transistors (BJTs) as the controlled power switch, was constructed during the current reporting period. The major motivation behind the construction of this new experimental power stage was to improve the circuit layout so as to reduce the effects of stray circuit parasitic inductances resulting from excess circuit lead lengths and circuit loops, and to take advantage of the layout improvements which could be made when some recently-available power components, particularly power diodes and polypropylene filter capacitors, were incorporated into the design.

  7. Thermal management of space-based, high-power solid-state RF amplifiers. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Rose, M.F.; Chow, L.C.; Johnson, J.H.


    The advanced weapons concepts envisioned by the SDIO employed a wide array of highly energetic devices, which due to inefficiencies, generate large quantities of waste heat. Power and thermal management are integrally related. In the vacuum of space, disposing of waste energy is a major problem which can contribute as much as 50% to the overall spacecraft mass and volume. The problem becomes more acute as the temperature at which the energy must be rejected is lowered. In an earlier study, thermal management issues associated with megawatt class RF microwave tubes were explored to determine if there were simple, approximately mass neutral schemes which might be adapted to dispose of the waste energy generated within a tube collector operating in space. The assumptions for that study were: (1) Tubes were in the megawatt class-70% efficient for single simple collector and 90% efficient for depressed collectors, (2) On-board, super critical hydrogen was available at a pressure of 35 bars and a temperature of 35 K. (3) The largest single event run time was 500 seconds. (4) The device would be dormant for long periods of time, be required to become active in tens of seconds followed by long periods of dormancy. (5) The only allowable effluent is hydrogen. (6) System impact must be minimal.

  8. CFD Ventilation Study for the Human Powered Centrifuge at the International Space Station (United States)

    Son, Chang H.


    The Human Powered Centrifuge (HPC) is a hyper gravity facility that will be installed on board the International Space Station (ISS) to enable crew exercises under the artificial gravity conditions. The HPC equipment includes a bicycle for long-term exercises of a crewmember that provides power for rotation of HPC at a speed of 30 rpm. The crewmember exercising vigorously on the centrifuge generates the amount of carbon dioxide of several times higher than a crewmember in ordinary conditions. The goal of the study is to analyze the airflow and carbon dioxide distribution within Pressurized Multipurpose Module (PMM) cabin. The 3D computational model included PMM cabin. The full unsteady formulation was used for airflow and CO2 transport modeling with the so-called sliding mesh concept is considered in the rotating reference frame while the rest of the cabin volume is considered in the stationary reference frame. The localized effects of carbon dioxide dispersion are examined. Strong influence of the rotating HPC equipment on the CO2 distribution is detected and discussed.

  9. A Low-Power High-Speed Smart Sensor Design for Space Exploration Missions (United States)

    Fang, Wai-Chi


    A low-power high-speed smart sensor system based on a large format active pixel sensor (APS) integrated with a programmable neural processor for space exploration missions is presented. The concept of building an advanced smart sensing system is demonstrated by a system-level microchip design that is composed with an APS sensor, a programmable neural processor, and an embedded microprocessor in a SOI CMOS technology. This ultra-fast smart sensor system-on-a-chip design mimics what is inherent in biological vision systems. Moreover, it is programmable and capable of performing ultra-fast machine vision processing in all levels such as image acquisition, image fusion, image analysis, scene interpretation, and control functions. The system provides about one tera-operation-per-second computing power which is a two order-of-magnitude increase over that of state-of-the-art microcomputers. Its high performance is due to massively parallel computing structures, high data throughput rates, fast learning capabilities, and advanced VLSI system-on-a-chip implementation.

  10. Design of multihundred-watt dynamic isotope power system for robotic space missions (United States)

    Bents, D. J.; Geng, S. M.; Schreiber, J. G.; Withrow, C. A.; Schmitz, P. C.; McComas, T. J.

    The design of a multihundred-watt dynamic isotope power system (DIPS) based on the US Department of Energy (DOE) general-purpose heat source (GPHS) and small (multihundred-watt) free-piston Stirling engine (FPSE) is described as a potential lower cost alternative to radioisotope thermoelectric generators (RTGs). The design is targeted at the power needs of future unmanned deep space and planetary surface exploration missions. Since the competitive potential of FPSE as an isotope convertor was first identified, work has focused on the feasibility of directly integrating GPHS with the Stirling heater head. Thermal modeling of various radiatively coupled heat source/heater head geometries has been performed using data furnished by the developers of FPSE and GPHS. The analysis indicates that, for the 1050 K heater head configurations considered, GPHS fuel clad temperatures remain safe operating limits under all conditions including shutdown of one engine on a twin engine unit. Based on these results, preliminary characterizations of multihundred-watt units have been established. They indicate that, per electrical watt, the GPHS/small Stirling DIPS will be roughly equivalent to MOD RTG in size and mass but will require about a third the amount of isotope fuel.

  11. Space Station Module Power Management and Distribution System (SSM/PMAD) (United States)

    Miller, William; Britt, Daniel; Elges, Michael; Myers, Chris


    This report provides an overview of the Space Station Module Power Management and Distribution (SSM/PMAD) testbed system and describes recent enhancements to that system. Four tasks made up the original contract: (1) common module power management and distribution system automation plan definition; (2) definition of hardware and software elements of automation; (3) design, implementation and delivery of the hardware and software making up the SSM/PMAD system; and (4) definition and development of the host breadboard computer environment. Additions and/or enhancements to the SSM/PMAD test bed that have occurred since July 1990 are reported. These include: (1) rehosting the MAESTRO scheduler; (2) reorganization of the automation software internals; (3) a more robust communications package; (4) the activity editor to the MAESTRO scheduler; (5) rehosting the LPLMS to execute under KNOMAD; implementation of intermediate levels of autonomy; (6) completion of the KNOMAD knowledge management facility; (7) significant improvement of the user interface; (8) soft and incipient fault handling design; (9) intermediate levels of autonomy, and (10) switch maintenance.

  12. A direct current rectification scheme for microwave space power conversion using traveling wave electron acceleration (United States)

    Manning, Robert M.


    The formation of the Vision-21 conference held three years ago allowed the present author to reflect and speculate on the problem of converting electromagnetic energy to a direct current by essentially reversing the process used in traveling wave tubes that converts energy in the form of a direct current to electromagnetic energy. The idea was to use the electric field of the electromagnetic wave to produce electrons through the field emission process and accelerate these electrons by the same field to produce an electric current across a large potential difference. The acceleration process was that of cyclotron auto-resonance. Since that time, this rather speculative ideas has been developed into a method that shows great promise and for which a patent is pending and a prototype design will be demonstrated in a potential laser power beaming application. From the point of view of the author, a forum such as Vision-21 is becoming an essential component in the rather conservative climate in which our initiatives for space exploration are presently formed. Exchanges such as Vision-21 not only allows us to deviate from the 'by-the-book' approach and rediscover the ability and power in imagination, but provides for the discussion of ideas hitherto considered 'crazy' so that they may be given the change to transcend from the level of eccentricity to applicability.

  13. Computational Fluid Dynamics Ventilation Study for the Human Powered Centrifuge at the International Space Station (United States)

    Son, Chang H.


    The Human Powered Centrifuge (HPC) is a facility that is planned to be installed on board the International Space Station (ISS) to enable crew exercises under the artificial gravity conditions. The HPC equipment includes a "bicycle" for long-term exercises of a crewmember that provides power for rotation of HPC at a speed of 30 rpm. The crewmember exercising vigorously on the centrifuge generates the amount of carbon dioxide of about two times higher than a crewmember in ordinary conditions. The goal of the study is to analyze the airflow and carbon dioxide distribution within Pressurized Multipurpose Module (PMM) cabin when HPC is operating. A full unsteady formulation is used for airflow and CO2 transport CFD-based modeling with the so-called sliding mesh concept when the HPC equipment with the adjacent Bay 4 cabin volume is considered in the rotating reference frame while the rest of the cabin volume is considered in the stationary reference frame. The rotating part of the computational domain includes also a human body model. Localized effects of carbon dioxide dispersion are examined. Strong influence of the rotating HPC equipment on the CO2 distribution detected is discussed.

  14. Bimodal regime in young massive clusters leading to subsequent stellar generations

    CERN Document Server

    Wünsch, Richard; Tenorio-Tagle, Guillermo; Muñoz-Tuñón, Casiana; Ehlerová, Soňa


    Massive stars in young massive clusters insert tremendous amounts of mass and energy into their surroundings in the form of stellar winds and supernova ejecta. Mutual shock-shock collisions lead to formation of hot gas, filling the volume of the cluster. The pressure of this gas then drives a powerful cluster wind. However, it has been shown that if the cluster is massive and dense enough, it can evolve in the so--called bimodal regime, in which the hot gas inside the cluster becomes thermally unstable and forms dense clumps which are trapped inside the cluster by its gravity. We will review works on the bimodal regime and discuss the implications for the formation of subsequent stellar generations. The mass accumulates inside the cluster and as soon as a high enough column density is reached, the interior of the clumps becomes self-shielded against the ionising radiation of stars and the clumps collapse and form new stars. The second stellar generation will be enriched by products of stellar evolution from t...

  15. The origin of the galaxy color bimodality (United States)

    Aragón-Calvo, M. A.; Neyrinck, Mark C.; Silk, Joseph


    The star formation history of galaxies is a complex process usually considered to be stochastic in nature, for which we can only give average descriptions such as the color-density relation. In this work we follow star-forming gas particles in a hydrodynamical N-body simulation back in time in order to study their initial spatial configuration. By keeping record of the time when a gas particle started forming stars we can produce Lagrangian gas-star isochrone surfaces delineating the surfaces of accreting gas that begin producing stars at different times. These surfaces form a complex a network of filaments in Eulerian space from which galaxies accrete cold gas. Lagrangian accretion surfaces are closely packed inside dense regions, intersecting each other, and as a result galaxies inside proto-clusters stop accreting gas early, naturally explaining the color dependence on density. The process described here has a purely gravitational / geometrical origin, arguably operating at a more fundamental level than complex processes such as AGN and supernovae, and providing a conceptual origin for the color-density relation.

  16. Fluoride-assisted synthesis of bimodal microporous SSZ-13 zeolite. (United States)

    Zhu, Xiaochun; Kosinov, Nikolay; Hofmann, Jan P; Mezari, Brahim; Qian, Qingyun; Rohling, Roderigh; Weckhuysen, Bert M; Ruiz-Martínez, Javier; Hensen, Emiel J M


    The presence of small amount of fluoride in alkaline hydrothermal synthesis of SSZ-13 zeolite yields bimodal microporous particles with substantially improved performance in the methanol-to-olefins (MTO) reaction. Hydrocarbon uptake measurements and fluorescence microspectroscopy of spent catalysts demonstrate enhanced diffusion through micropores at the grain boundaries of nanocrystals running through the zeolite particles. Fluoride-assisted SSZ-13 synthesis is a cheap and scalable approach to optimize the performance of MTO zeolite catalysts.

  17. Mobile Education: Towards Affective Bi-modal Interaction for Adaptivity

    Directory of Open Access Journals (Sweden)

    Efthymios Alepis


    Full Text Available One important field where mobile technology can make significant contributions is education. However one criticism in mobile education is that students receive impersonal teaching. Affective computing may give a solution to this problem. In this paper we describe an affective bi-modal educational system for mobile devices. In our research we describe a novel approach of combining information from two modalities namely the keyboard and the microphone through a multi-criteria decision making theory.

  18. Bimodal effects of cinnamaldehyde and camphor on mouse TRPA1. (United States)

    Alpizar, Yeranddy A; Gees, Maarten; Sanchez, Alicia; Apetrei, Aurelia; Voets, Thomas; Nilius, Bernd; Talavera, Karel


    TRPA1 is a nonselective cation channel activated by a wide variety of noxious chemicals. Intriguingly, several TRPA1 modulators induce a bimodal effect, activating the channel at micromolar concentrations and inhibiting it at higher concentrations. Here we report the bimodal action of cinnamaldehyde (CA) and camphor, which are thus far reported as agonist and antagonist of TRPA1, respectively. Whole-cell patch-clamp experiments in TRPA1-expressing CHO cells revealed that, as previously reported, extracellular application of 100 μM CA strongly stimulates TRPA1 currents. However, subsequent application of 3 mM CA induced fast and reversible current inhibition. Application of 3 mM CA in basal conditions induced a rather small current increase, followed by current inhibition and a dramatic rebound of current amplitude upon washout. These observations are reminiscent of the effects of TRPA1 modulators having bimodal effects, e.g., menthol and nicotine. In line with previous reports, extracellular application of 1 mM camphor induced a decrease of basal TRPA1 currents. However, the current amplitude showed a significant overshoot upon washout. On the other hand, application of 100 μM camphor induced a 3-fold increase of the basal current amplitude measured at -75 mV. The bimodal effects of CA and camphor on TRPA1 were also observed in microfluorimetric measurements of intracellular Ca(2+) in intact TRPA1-expressing CHO cells and in primary cultures of mouse dorsal root ganglion neurons. These findings are essential for the understanding of the complex sensory properties of these compounds, as well as their utility when used to study the pathophysiological relevance of TRPA1.

  19. Probabilistic Physics-Based Risk Tools Used to Analyze the International Space Station Electrical Power System Output (United States)

    Patel, Bhogila M.; Hoge, Peter A.; Nagpal, Vinod K.; Hojnicki, Jeffrey S.; Rusick, Jeffrey J.


    This paper describes the methods employed to apply probabilistic modeling techniques to the International Space Station (ISS) power system. These techniques were used to quantify the probabilistic variation in the power output, also called the response variable, due to variations (uncertainties) associated with knowledge of the influencing factors called the random variables. These uncertainties can be due to unknown environmental conditions, variation in the performance of electrical power system components or sensor tolerances. Uncertainties in these variables, cause corresponding variations in the power output, but the magnitude of that effect varies with the ISS operating conditions, e.g. whether or not the solar panels are actively tracking the sun. Therefore, it is important to quantify the influence of these uncertainties on the power output for optimizing the power available for experiments.

  20. Working group report on advanced high-voltage high-power and energy-storage space systems (United States)

    Cohen, H. A.; Cooke, D. L.; Evans, R. W.; Hastings, D.; Jongeward, G.; Laframboise, J. G.; Mahaffey, D.; Mcintyre, B.; Pfizer, K. A.; Purvis, C.


    Space systems in the future will probably include high-voltage, high-power energy-storage and -production systems. Two such technologies are high-voltage ac and dc systems and high-power electrodynamic tethers. The working group identified several plasma interaction phenomena that will occur in the operation of these power systems. The working group felt that building an understanding of these critical interaction issues meant that several gaps in our knowledge had to be filled, and that certain aspects of dc power systems have become fairly well understood. Examples of these current collection are in quiescent plasmas and snap over effects. However, high-voltage dc and almost all ac phenomena are, at best, inadequately understood. In addition, there is major uncertainty in the knowledge of coupling between plasmas and large scale current flows in space plasmas. These gaps in the knowledge are addressed.

  1. Overview of NASA Lewis Research Center free-piston Stirling engine technology activities applicable to space power systems (United States)

    Slaby, Jack G.


    A brief overview is presented of the development and technological activities of the free-piston Stirling engine. The engine started as a small scale fractional horsepower engine which demonstrated basic engine operating principles and the advantages of being hermetically sealed, highly efficient, and simple. It eventually developed into the free piston Stirling engine driven heat pump, and then into the SP-100 Space Reactor Power Program from which came the Space Power Demonstrator Engine (SPDE). The SPDE successfully operated for over 300 hr and delivered 20 kW of PV power to an alternator plunger. The SPDE demonstrated that a dynamic power conversion system can, with proper design, be balanced; and the engine performed well with externally pumped hydrostatic gas bearings.

  2. Compatibility of Space Nuclear Power Plant Materials in an Inert He/Xe Working Gas Containing Reactive Impurities

    Energy Technology Data Exchange (ETDEWEB)

    MM Hall


    A major materials selection and qualification issue identified in the Space Materials Plan is the potential for creating materials compatibility problems by combining dissimilar reactor core, Brayton Unit and other power conversion plant materials in a recirculating, inert He/Xe gas loop containing reactive impurity gases. Reported here are results of equilibrium thermochemical analyses that address the compatibility of space nuclear power plant (SNPP) materials in high temperature impure He gas environments. These studies provide early information regarding the constraints that exist for SNPP materials selection and provide guidance for establishing test objectives and environments for SNPP materials qualification testing.

  3. Nonlinear response speedup in bimodal visual-olfactory object identification

    Directory of Open Access Journals (Sweden)

    Richard eHöchenberger


    Full Text Available Multisensory processes are vital in the perception of our environment. In the evaluation of foodstuff, redundant sensory inputs not only assist the identification of edible and nutritious substances, but also help avoiding the ingestion of possibly hazardous substances. While it is known that the non-chemical senses interact already at early processing levels, it remains unclear whether the visual and olfactory senses exhibit comparable interaction effects. To address this question, we tested whether the perception of congruent bimodal visual-olfactory objects is facilitated compared to unimodal stimulation. We measured response times (RT and accuracy during speeded object identification. The onset of the visual and olfactory constituents in bimodal trials was physically aligned in the first and perceptually aligned in the second experiment. We tested whether the data favored coactivation or parallel processing consistent with race models. A redundant-signals effect was observed for perceptually aligned redundant stimuli only, i.e. bimodal stimuli were identified faster than either of the unimodal components. Analysis of the RT distributions and accuracy data revealed that these observations could be explained by a race model. More specifically, visual and olfactory channels appeared to be operating in a parallel, positively dependent manner. While these results suggest the absence of early sensory interactions, future studies are needed to substantiate this interpretation.

  4. Does bimodal stimulus presentation increase ERP components usable in BCIs? (United States)

    Thurlings, Marieke E.; Brouwer, Anne-Marie; Van Erp, Jan B. F.; Blankertz, Benjamin; Werkhoven, Peter J.


    Event-related potential (ERP)-based brain-computer interfaces (BCIs) employ differences in brain responses to attended and ignored stimuli. Typically, visual stimuli are used. Tactile stimuli have recently been suggested as a gaze-independent alternative. Bimodal stimuli could evoke additional brain activity due to multisensory integration which may be of use in BCIs. We investigated the effect of visual-tactile stimulus presentation on the chain of ERP components, BCI performance (classification accuracies and bitrates) and participants’ task performance (counting of targets). Ten participants were instructed to navigate a visual display by attending (spatially) to targets in sequences of either visual, tactile or visual-tactile stimuli. We observe that attending to visual-tactile (compared to either visual or tactile) stimuli results in an enhanced early ERP component (N1). This bimodal N1 may enhance BCI performance, as suggested by a nonsignificant positive trend in offline classification accuracies. A late ERP component (P300) is reduced when attending to visual-tactile compared to visual stimuli, which is consistent with the nonsignificant negative trend of participants’ task performance. We discuss these findings in the light of affected spatial attention at high-level compared to low-level stimulus processing. Furthermore, we evaluate bimodal BCIs from a practical perspective and for future applications.

  5. High Efficiency Quantum Dot III-V Multijunction Solar Cell for Space Power Project (United States)

    National Aeronautics and Space Administration — We are proposing to utilize quantum dots to develop a super high-efficiency multijunction III-V solar cell for space. In metamorphic triple junction space solar...

  6. Reacting to nuclear power systems in space: American public protests over outer planetary probes since the 1980s (United States)

    Launius, Roger D.


    The United States has pioneered the use of nuclear power systems for outer planetary space probes since the 1970s. These systems have enabled the Viking landings to reach the surface of Mars and both Pioneers 10 and 11 and Voyagers 1 and 2 to travel to the limits of the solar system. Although the American public has long been concerned about safety of these systems, in the 1980s a reaction to nuclear accidents - especially the Soviet Cosmos 954 spacecraft destruction and the Three Mile Island nuclear power plant accidents - heightened awareness about the hazards of nuclear power and every spacecraft launch since that time has been contested by opponents of nuclear energy. This has led to a debate over the appropriateness of the use of nuclear power systems for spacecraft. It has also refocused attention on the need for strict systems of control and rigorous checks and balances to assure safety. This essay describes the history of space radioisotope power systems, the struggles to ensure safe operations, and the political confrontation over whether or not to allow the launch the Galileo and Cassini space probes to the outer planets. Effectively, these efforts have led to the successful flights of 12 deep space planetary probes, two-thirds of them operated since the accidents of Cosmos 954, Three Mile Island, and Chernobyl.

  7. Current Status of Study on Hydrogen Production with Space Solar Power Systems (SSPS) (United States)

    Mori, M.; Kagawa, H.; Nagayama, H.; Saito, Y.


    Japan Aerospace Exploration Agency (JAXA) has been conducting studies on Space Solar Power Systems (SSPS) using microwave and laser beams for years since FY1998 organizing a special committee and working groups. The microwave based SSPS are huge solar power systems that generate GW power by solar cells. The electric power is transmitted via microwave from the SSPS to the ground. In the laser based SSPS, a solar condenser equipped with lenses or mirrors and laser-generator would be put into orbit. A laser beam would be sent to Earth-based hydrogen generating device. We are proposing a roadmap that consists of a stepwise approach to achieve commercial SSPS in 20-30 years. The first step is 50kW class Technology Demonstration Satellite to demonstrate microwave power transmission. The second step is to demonstrate robotic assembly of 10MW class large scale flexible structure in space on ISS co-orbit. The third step is to build a prototype SSPS in GEO. The final step is to build commercial SSPS in GEO. We continue the study of SSPS concepts and architectures, technology flight demonstration and major technology development. System design of tens of kW class Technology Demonstration Satellite and conceptual study of 10MW class demonstration system on ISS co-orbit are also conducted. Several key technologies which are needed to be developed in appropriate R&D roadmap, such as high-voltage solar cell array, fiber type of direct solar pumping solid-state laser, high efficiency magnetron, thermal control technology and control technology of large scale flexible structure etc. are also investigated. In the study of concept design of commercial SSPS mentioned above, we have studied some configurations of both microwave based SSPS and laser based SSPS. In case of microwave based SSPS, the solar energy must be converted to electricity and then converted to a microwave beam. The on-ground rectifying antenna will collect the microwave beam and convert it to electricity to connect

  8. Application of U10Mo Fuel for Space Fission Power Applications - White Paper

    Energy Technology Data Exchange (ETDEWEB)

    James Werner


    A novel reactor design has been proposed for space applications to provide hundreds of watts to one or two kilowatts of electrical power. The reactor concept proposed uses the alloy U10Mo (uranium with 10 weight percent molybdenum) as the fuel. This fuel was selected for its high uranium density, high thermal conductivity, and excellent neutronic characteristics for this application. The core is surrounded by a BeO reflector. Heat is carried from the reactor by liquid metal heat pipes. A shadow shield of LiH tungsten is also utilized to reduce the neutron and gamma radiation dose to the rest of the spacecraft. This design represents a best effort at minimizing the complexity of the fission system and reducing the mass of the system. The compact nature of the block UMo core and BeO radial reflector allows the reactor diameter to be as small as practical while still meeting the neutronic and thermal power demands. This directly results in a reduced shield mass since the reactor diameter dictates the footprint of the radiation shield. The use of heat pipes offers a straightforward primary heat transport approach using proven liquid-metal heat pipe technology. Further, the elimination of a liquid core coolant system heat transport components, both at the reactor side and radiator side, contributes to reducing the total part-count and lowering system mass. The proposed reactor is using a fuel that is being developed by DOE, but there are significant differences in the fuels enrichment, operating conditions and the physical shape of the fuel itself. This paper attempts to highlight some of the basic consideration and needs that would be expected to be met in developing this fuel and qualifying it for use.

  9. A new type of accelerator power supply based on voltage-type space vector PWM rectification technology

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Fengjun, E-mail: [Institute of Modern Physics, CAS, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Gao, Daqing; Shi, Chunfeng; Huang, Yuzhen [Institute of Modern Physics, CAS, Lanzhou 730000 (China); Cui, Yuan [Institute of Modern Physics, CAS, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Yan, Hongbin [Institute of Modern Physics, CAS, Lanzhou 730000 (China); Zhang, Huajian [Institute of Modern Physics, CAS, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Wang, Bin [University of Chinese Academy of Sciences, Beijing 100049 (China); Li, Xiaohui [Institute of Modern Physics, CAS, Lanzhou 730000 (China)


    To solve the problems such as low input power factor, a large number of AC current harmonics and instable DC bus voltage due to the diode or thyristor rectifier used in an accelerator power supply, particularly in the Heavy Ion Research Facility in Lanzhou-Cooler Storage Ring (HIRFL-CSR), we designed and built up a new type of accelerator power supply prototype base on voltage-type space vector PWM (SVPWM) rectification technology. All the control strategies are developed in TMS320C28346, which is a digital signal processor from TI. The experimental results indicate that an accelerator power supply with a SVPWM rectifier can solve the problems above well, and the output performance such as stability, tracking error and ripple current meet the requirements of the design. The achievement of prototype confirms that applying voltage-type SVPWM rectification technology in an accelerator power supply is feasible; and it provides a good reference for design and build of this new type of power supply. - Highlights: • Applying SVPWM rectification technology in an accelerator power supply improves its grid-side performance. • New Topology and its control strategies make an accelerator power supply have bidirectional power flow ability. • Hardware and software of controller provide a good reference for design of this new type of power supply.

  10. Unimodular bimode gravity and the coherent scalar-graviton field as galaxy dark matter

    CERN Document Server

    Pirogov, Yu F


    The explicit violation of general relativity is adopted as an origin of dark matter and dark energy of the gravitational nature. The violation of the local scale invariance alone, with the residual unimodular invariance/relativity, is considered as a paradigm. Besides the four-volume preserving deformation mode -- the transverse-tensor graviton -- the metric comprises a compression mode -- the scalar graviton, or the {\\em systolon}. The unimodular invariant metric theory of the bimode gravity is worked out. Due to a non-dynamical scalar density -- the dark {\\em modulus} -- the theory is general covariant. To substantially reduce the primordial ambiguity of the effective Lagrangian a dynamical global symmetry -- the {\\em compression} one -- is superimposed at the classical level, with the subsequent spontaneous breaking of the symmetry displayed. The static spherically symmetric field configuration in the empty, but possibly for the origin, space is studied. A three-parameter solution describing a new static s...

  11. A Burst Mode, Ultrahigh Temperature UF4 Vapor Core Reactor Rankine Cycle Space Power System Concept (United States)

    Dugan, E. T.; Kahook, S. D.; Diaz, N. J.


    Static and dynamic neutronic analyses have been performed on an innovative burst mode (100's of MW output for a few thousand seconds) Ulvahigh Temperature Vapor Core Reactor (UTVR) space nuclear power system. The NVTR employs multiple, neutronically-coupled fissioning cores and operates on a direct, closed Rankine cycle using a disk Magnetohydrodynamic (MHD) generater for energy conversion. The UTVR includes two types of fissioning core regions: (1) the central Ultrahigh Temperature Vapor Core (UTVC) which contains a vapor mixture of highly enriched UF4 fuel and a metal fluoride working fluid and (2) the UF4 boiler column cores located in the BeO moderator/reflector region. The gaseous nature of the fuel the fact that the fuel is circulating, the multiple coupled fissioning cores, and the use of a two phase fissioning fuel lead to unique static and dynamic neutronic characteristics. Static neutronic analysis was conducted using two-dimensional S sub n, transport theory calculations and three-dimensional Monte Carlo transport theory calculations. Circulating-fuel, coupled-core point reactor kinetics equations were used for analyzing the dynamic behavior of the UTVR. In addition to including reactivity feedback phenomena associated with the individual fissioning cores, the effects of core-to-core neutronic and mass flow coupling between the UTVC and the surrounding boiler cores were also included in the dynamic model The dynamic analysis of the UTVR reveals the existence of some very effectlve inherent reactivity feedback effects that are capable of quickly stabilizing this system, within a few seconds, even when large positive reactivity insertions are imposed. If the UTVC vapor fuel density feedback is suppressed, the UTVR is still inherently stable because of the boiler core liquid-fuel volume feedback; in contrast, suppression of the vapor fuel density feedback in 'conventional" gas core cavity reactors causes them to become inherently unstable. Due to the

  12. Bellows-Type Accumulators for Liquid Metal Loops of Space Reactor Power Systems (United States)

    Tournier, Jean-Michel; El-Genk, Mohamed S.


    In many space nuclear power systems, the primary and/or secondary loops use liquid metal working fluids, and require accumulators to accommodate the change in the liquid metal volume and maintain sufficient subcooling to avoid boiling. This paper developed redundant and light-weight bellows-type accumulators with and without a mechanical spring, and compared the operating condition and mass of the accumulators for different types of liquid metal working fluids and operating temperatures: potassium, NaK-78, sodium and lithium loops of a total capacity of 50 liters and nominal operating temperatures of 840 K, 860 K, 950 K and 1340 K, respectively. The effects of using a mechanical spring and different structural materials on the design, operation and mass of the accumulators are also investigated. The structure materials considered include SS-316, Hastelloy-X, C-103 and Mo-14Re. The accumulator without a mechanical spring weighs 23 kg and 40 kg for a coolant subcooling of 50 K and 100 K, respectively, following a loss of the fill gas. The addition of a mechanical spring comes with a mass penalty, in favor of higher redundancy and maintaining a higher liquid metal subcooling.

  13. Zebrafish brain mapping--standardized spaces, length scales, and the power of N and n. (United States)

    Hunter, Paul R; Hendry, Aenea C; Lowe, Andrew S


    Mapping anatomical and functional parameters of the zebrafish brain is moving apace. Research communities undertaking such studies are becoming ever larger and more diverse. The unique features, tools, and technologies associated with zebrafish are propelling them as the 21st century model organism for brain mapping. Uniquely positioned as a vertebrate model system, the zebrafish enables imaging of anatomy and function at different length scales from intraneuronal compartments to sparsely distributed whole brain patterns. With a variety of diverse and established statistical modeling and analytic methods available from the wider brain mapping communities, the richness of zebrafish neuroimaging data is being realized. The statistical power of population observations (N) within and across many samples (n) projected onto a standardized space will provide vast databases for data-driven biological approaches. This article reviews key brain mapping initiatives at different levels of scale that highlight the potential of zebrafish brain mapping. By way of introduction to the next wave of brain mappers, an accessible introduction to the key concepts and caveats associated with neuroimaging are outlined and discussed.

  14. Integrated Orbit, Attitude, and Structural Control Systems Design for Space Solar Power Satellites (United States)

    Wie, Bong; Roithmayr, Carlos M.


    The major objective of this study is to develop an integrated orbit, attitude, and structural control systems architecture for very large Space Solar Power Satellites (SSPS) in geosynchronous orbit. This study focuses on the 1.2-GW Abacus SSPS concept characterized by a 3.2 x 3.2 km solar-array platform, a 500-m diameter microwave beam transmitting antenna, and a 500 x 700 m earth-tracking reflector. For this baseline Abacus SSPS configuration, we derive and analyze a complete set of mathematical models, including external disturbances such as solar radiation pressure, microwave radiation, gravity-gradient torque, and other orbit perturbation effects. The proposed control systems architecture utilizes a minimum of 500 1-N electric thrusters to counter, simultaneously, the cyclic pitch gravity-gradient torque, the secular roll torque caused by an offset of the center-of-mass and center-of-pressure, the cyclic roll/yaw microwave radiation torque, and the solar radiation pressure force whose average value is about 60 N.

  15. Measurement of Redshift Space Power Spectrum for BOSS galaxies and the Growth Rate at redshift 0.57

    CERN Document Server

    Li, Zhigang; Zhang, Pengjie; Cheng, Dalong


    We present a measurement of two-dimensional (2D) redshift-space power spectrum for the Baryon Oscillation Spectroscopic Survey (BOSS) Data Release 11 CMASS galaxies in the North Galactic Cap (NGC) based on the method developed by Jing & Borner (2001). In this method, we first measure the 2D redshift-space correlation function for the CMASS galaxies, and obtain the 2D power spectrum based on Fourier Transform of the correlation function. The method is tested with an N-body mock galaxy catalog, which demonstrates that the method can yield an accurate and unbiased measurement of the redshift-space power spectrum given the input 2D correlation function is correct. Compared with previous measurements in literature that are usually based on direct Fourier Transform in redshift space, our method has the advantages that the window function and shot-noise are fully corrected. In fact, our 2D power spectrum, by its construction, can accurately reproduce the 2D correlation function, and in the meanwhile can reproduc...

  16. Space, power and the body - the civil and uncivil as represented in the Voortrekker Monument and the Native Township Model

    NARCIS (Netherlands)

    Steenkamp, A.C.


    The relationship between space and power in pre-democratic South Africa was deliberately inclusive of some and excluded the other through its nature, location, ordering and limits. The thesis has as its focus this process as it pertains to two projects of the mid-20th century South African urban env

  17. 46 CFR 182.460 - Ventilation of spaces containing machinery powered by, or fuel tanks for, gasoline. (United States)


    ... accordance with ABYC H-2 (incorporated by reference; see 46 CFR 175.600) or 33 CFR 183, subpart K... 46 Shipping 7 2010-10-01 2010-10-01 false Ventilation of spaces containing machinery powered by... SECURITY (CONTINUED) SMALL PASSENGER VESSELS (UNDER 100 GROSS TONS) MACHINERY INSTALLATION...

  18. Test and evaluation of load converter topologies used in the Space Station Freedom power management and distribution dc test bed (United States)

    Lebron, Ramon C.; Oliver, Angela C.; Bodi, Robert F.


    Power components hardware in support of the Space Station freedom dc Electric Power System were tested. One type of breadboard hardware tested is the dc Load Converter Unit, which constitutes the power interface between the electric power system and the actual load. These units are dc to dc converters that provide the final system regulation before power is delivered to the load. Three load converters were tested: a series resonant converter, a series inductor switch-mode converter, and a switching full-bridge forward converter. The topology, operation principles, and test results are described, in general. A comparative analysis of the three units is given with respect to efficiency, regulation, short circuit behavior (protection), and transient characteristics.

  19. Fusion of Built in Test (BIT) Technologies with Embeddable Fault Tolerant Techniques for Power System and Drives in Space Exploration Project (United States)

    National Aeronautics and Space Administration — Impact Technologies has proposed development of an effective prognostic and fault accommodation system for critical DC power systems including PV systems. Overall...

  20. Game Changing Usage of High-Voltage Power Transmission Systems as Extremely Large Antennas for Space Physical and Geophysical Remote Imaging Project (United States)

    National Aeronautics and Space Administration — Geomagnetic storms drive geomagnetically induced currents (GIC) in high-voltage power transmission systems worldwide. GIC distribution in the transmission system is...