Advanced Power Sources for Space Missions (1989) / Chapter Skim
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2. Space Power Requirements and Selection Criteria
2. Space Power Requirements and Selection Criteria
Pages 9-23
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From page 9... ...
SD! Power Requirements for Housekeeping, Alert, and Burst Modes New U.S.
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From page 10... ...
Accordingly, unless considerable effort is made to develop SDI systems that minimize the alert-mode requirement, there may be so many kilowatt-hours of energy storage neededespecially if nonnuclear power subsystems are used- that the prime power subsystem would become a major factor in sizing the orbital platform. ~ Burst mode.
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Table 2-1 outlines salient features of these three SDI power modes. Power requirements need to be considered for the major potential SDI weapons and sensor systems that the SDI program is pursuing.
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Even for the 1990-1995 period, initial estimates of prime power requirements for electrically energized DEW systems tests at the White Sands Missile Range indicate that extremely high power levels having fast time-ramping capabilities must be provided during the tests. Only highly efficient prime power or power conversion technologies could qualify for space-based versions of such applications.
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From page 13... ...
These considerations impose certain constraints on candidate space power system, such as the size of solar arrays and the temperature of radiators needed to reject heat to space. Power requirements for non-SDI military missions can probably be satisfied with solar dynamic or small nuclear reactor power systems.
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From page 14... ...
of possible NASA needs for nuclear power sources lists approximately 20 possible missions with power requirements ranging from tens to hundreds of kilowatts. For Phase 1 of the Space Station's development, 75 kWe of average power*
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Commonality of Requirements Among Citric and Military Missions While the most demanding space-based power requirements are those of SDI, some projected civil or NASA applications under discussion could capitalize on the SDI investment. For example, to operate an outpost on the lunar surface, a power plant suitable for the SDI housekeeping mode may suit the utility needs.
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From page 16... ...
Bimodal operation providing both continuous and burst power capabilities may effectively address the combined mission requirements. The multimegawatt technology task of the SDIO Power Program should address these needs by providing for development of an integrated power technology base that considers both nuclear and nonnuclear multimegawatt power sources and combinations of those .
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From page 17... ...
Several critical issue areas in satisfying SDI space power requirements are discussed below without attempting to rank them by their relative importance; Al of them may be vital. Critical Issue Areas Figure 2-1 (based on the SPAS studies)
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OPEN CYCLE NUCLEAR (intermediate fixed mass plus relatively modest mass of consumable hydrogen) ~ ~— OPEN CYCLE CHEMICAL (low fixed mass plus relatively large mass of consumables such as hydrogen and oxygen)
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From page 19... ...
The SPAS studies addressed indiviclual space power system on tions. However, the spacecraft power supply needed to satisfy requirements for the three SDI power modes (housekeeping, alert, and burst modes)
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From page 20... ...
The optimum module size will depend on conversion efficiency, thermal management, power flow, and voltage levels, and may be in the same power range already experienced in the very-high-power radar and fusion fields; namely, between 1 and 10 MWe. Keeping components and subsystems small and modular also enables local control of faults and minimizes development time.
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the interim approach of formulating a list of general guidelines for survivability. Values are listed in that publication for maneuvering, hardness against x rays, and so on, and are probably satisfactory as interim survivability guidelines except for platforms in Tow earth orbit.
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From page 22... ...
, requirements for the alert mode are inadequately (refined, yet they appear to be a major design dete~iinant. llor that mode, the unprecedented high power levels, durations, and unusual t~me-profiles as well as the associated voltages and currents that are envisioned avid usually make extrapolation from previous experience quite risky and nnreliable.
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From page 23... ...
Pending such analysis, candidate power systems should be screened for their potential to satisfy Veteran SDIO survivabUity requirements, reserv~ng judgment as to when or whether t_ose requirements should constrain technology development. Convey the screening results to the advocates of those candidate power systems, to stimulate their finding ways to enhance survivability as they develop the technology.
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