Power Beaming to Space Using a Nuclear Reactor-Pumped Laser

IEEE Aerospace and Electronic Systems Magazine, 1992

BEAM-POWER SYSTEM Thisstudy,basedon two levelsof technology, applies In a beam-powersystem,as shown in Figure 1,the the power beamingconcept to four plannedsatellite power system and user are separated by >_.105km. constellations.The analysisshowsthatwithcurrently The central power system is coupled with a available technology, power beaming can provide transmitterto transmit power to each remote user; masssavingsto constellations in orbitsrangingfrom each remote user is equipped with a receiver to low earth orbit to geosynchronous orbit. Two receive power from the central power system. constellations, spacesurveillance and trackingsystem Selecting the transmitter and receiver involves and space based radar, can be supported with optimizing four parameters: 1) the transmission current technology. The other two constellations, distance,2) the transmissionfrequency,3) the power space-basedlaser array and boost surveillanceand leveltransmitted,and 4) thethermalrejectioncapacity tracking system,will require power and transmission of the components.The powertransmissiondistance systemimprovementsbeforetheir breakevenspecific is the key parameter for determining the operating mass is achieved. A doubling of SP-100 conversion frequency because the ratio of power received to efficiency from 10 to 20% would meet or exceed powertransmittedis a functionof the transmitterand breakevenfor these constellations, receiveraperturearea,thetransmissiondistance, and the operatingfrequency. INTRODUCTION Radio frequencies (a microwave system) and The power system is a major component of a opticalfrequencies(a lasersystem)are viable options spacesystem'ssize, mass,technicalcomplexity,and forwirelessenergytransmission in space. Microwave hence,cost. In current design,the energysource is technologyis availabletoday at 2.45 GHz.2'3 Solidan integral part of the mission satellite. Potentially state laser technology (a 0.833 micron laser significantbenefitscould be realizedby replacingthe transmitter and photovoltaic receiver) is being satellite's power system with a receiverand trans-developedand would be availableearly in the next mittingthe power via an energy beam from a distant century. 4 Both technologies are viable in the power satellite. 1 This concept parallelsthe terrestrial projectedtime frames beingconsideredfor transition central generatingstationwith its transmissiongrid. to power beaming. Therefore, system selection In this paper, the system components requiredfor becomes a tradeoff among the specific mission or power beaming implementation are outlined and energy application,the transmissiondistances, and appliedto severalproposedsatelliteconstellations to the end-use energy needs. demonstratethe feasibility of implementing power beaming. (a) Operated for the U.S. Department of Energy by Battelle Memorial Institute under Contract DE-ACO6-76RLO1830.

6th International Energy Conversion Engineering Conference (IECEC), 2008

As NASA's Space Exploration policy takes shape, one of the key issues that will affect all aspects of the exploration architecture is the ability to provide electric power to various surface locations on the moon, Mars, other planets or asteroids. This power should be available through daylight times as well as at night. The moon is an especially difficult case in this regard. While nuclear reactors and radioisotope power sources may be one choice for continuous power, it is the purpose of this paper to explore the advantages of power beaming by lasers and/or microwaves to provide power to a wide range of locations on the surface of the moon, Mars and Venus.

AIP Conference Proceedings, 1992

This report was prepared as an account of work sponsored by an agency of the United States Government. Ncither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, rccommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors e x p r d herein do not necessarily state or reflect those of the United States Government or any agency thereof.

Nasa Sti Recon Technical Report N, 1993

Earth-based laser sites beaming laser power to space assets have shown benefits over competing power system concepts for specific missions. Missions analyzed in this report that show benefits of laser beam power are low-Earth-orbit (LEO) to geosynchronous-Earth-orbit (GEO) transfer, LEO to low-lunar-orbit (LLO) cargo missions, and lunar-base power. Both laser-and solar-powered orbit transfer vehicles (OTV's) make a "tug" concept viable, which substantially reduces cumulative initial mass to LEO in comparison to chemical propulsion concepts. In addition, electric propulsion OTV's powered by a laser beam have shorter trip times to and from GEO than do competing OTV's powered solely by the Sun. A round-trip savings of 3 months was calculated for the use of a laser OTV tug instead of a solar OTV tug. Lunar cargo missions utilizing laser electric propulsion from Earth-orbit to LLO show substantial mass saving to LEO over chemical propulsion systems. Lunar-base power system options were compared on a landed-mass basis. Photovoltaics with regenerative fuel cells, reactor-based systems, and laser-based systems were sized to meet a generic lunar-base power profile. A laser-based system begins to show landed-mass benefits over reactor-based systems when proposed production facilities on the Moon require power levels greater than-300 kWe. The performance of conventional solar cells, when iJlu111i11Jtt~d by laser light, shows a potential efficiency improvement of a factor of 2. The greatest challenge to achieving this improvement is increasing the cell's low response to pulsed free-electron laser illumination at very high intensity levels. Benefit/cost ratios of laser power systems for an OTV, both to GEO and LLO, and for a lunar base were calculated to be greater than 1. Here benefit was defined as the transportation cost savings, and cost was defined as the cost of installing and operating four Earth laser sites.

2018 International Energy Conversion Engineering Conference

A key element of space nuclear power systems is the energy conversion subsystem that converts the nuclear heat into electrical power. Nuclear systems provide a favorable option for missions that require long-duration power in hostile space environments where sunlight for solar power is absent or limited. There are two primary nuclear power technology options. Radioisotope Power System (RPS) utilize the natural decay heat from Pu238 to generate electric power levels up to about one kilowatt. Fission Power System (FPS) rely on a sustained fission reaction of U235 and offer the potential to supply electric power from kilowatts to megawatts. Example missions for nuclear power include Mars science rovers (e.g. Curiosity, Mars 2020), lunar and Mars surface landers, crewed surface outposts, deep space planetary orbiters, Ocean World science landers, and robotic space probes that utilize nuclear electric propulsion (NEP). This paper examines the energy conversion technology options that can be used with RPS and FPS, and provides an assessment of their relative performance. Nuclear systems provide a favorable option for missions that require long-duration power in hostile space environments where sunlight for solar power is absent or limited. Example missions include Mars science rovers (e.g. Curiosity, Mars 2020), lunar and Mars surface landers, crewed surface outposts, deep space planetary orbiters, Ocean World science landers, and robotic space probes that utilize nuclear electric propulsion (NEP). There are two primary nuclear power technology options: Radioisotope Power Systems (RPS) and Fission Power Systems (FPS). RPS utilize the natural decay heat from Pu238 to generate electric power levels up to about one kilowatt. The NASA Science Mission Directorate (SMD) RPS Program works in partnership with the Department of Energy (DOE) to produce the Pu238 heat sources, supply RPS and related services to flight missions, and develop new power conversion technologies. RPS have been a staple in NASA missions since the 1969 Nimbus III mission with a portfolio that includes Apollo, Pioneer, Viking, Voyager, Cassini, Pluto New Horizons, and most recently, Mars Curiosity. The current class of RPS utilize General Purpose Heat Source (GPHS) modules that supply approximately 250 Watts-thermal at Beginning-of-Life (BOL). Each GPHS module includes four fuel pellets that contain about 0.6 kg of plutonium-oxide. This fuel form has been in production since the late 1980s when the first GPHS Radioisotope Thermoelectric Generator (RTG) was flown on the Galileo mission. The largest RPS mission ever flown was Cassini (1997) which used three GPHS RTGs to supply nearly 900 Watts at launch using a total of 54 GPHS. The current version is the Multi-Mission RTG (MMRTG) designed to produce about 110 Watts at launch using eight GPHS modules. The MMRTG was first used on Mars Curiosity (Figure ) and is slated for use on the upcoming Mars 2020 rover. FPS rely on a sustained fission reaction of U235 and offer the potential to supply electric power from kilowatts to megawatts. The U.S. has flown only one FPS, in 1965. The 500 Watt SNAP 10A (Figure ) operated for 43 days before a spacecraft malfunction (unrelated to the FPS) caused a premature ending to the mission. NASA and DOE have attempted to develop FPS multiple times since the SNAP 10A, including SP-100 in the late 1980s and Prometheus in the early 2000s. In general, NASA's efforts to develop a space-qualified FPS fell short due to technical complexity, high development costs, and aggressive performance claims. These past attempts were typically accompanied by the need to develop new reactor fuel, structural materials and balance-of-plant components for a system that was bound by mission needs to produce high power at low mass with long operational life. This is a risky combination that undoubtedly contributed to the poor record of success in past programs.