Nuclear fission reactors for piloted deep space vehicles

Stephen Schmitt

November 26, 2012

Nuclear fission reactors can provide the large quantities of energy needed to propel piloted interplanetary and possibly interstellar spacecraft. Chemical energy will very likely prove to be impractical for piloted space travel much beyond the moon. Some form of solar energy could be developed to reach Mars. However, it is likely that more ambitious goals would take hold once Mars is reached. Solar energy technology probably could not be improved upon for piloted space travel further from the sun than Mars, so an investment in this technology probably would be lost.

Development of nuclear fission reactor technology for space travel applications is a good investment since it would eventually enable development of piloted vehicles that can reach virtually any point in the solar system and return to the earth. Also, continued improvement to this technology should eventually make it possible to at least send robotic exploration vehicles to nearby stars. Using nuclear energy in space is not new; during the cold war the USSR put nuclear reactors in LEO to power its radar ocean reconnaissance satellites and we put an experimental reactor, SNAP-10A in orbit (it is still there). Many deep space probes that NASA has launched use radio isotope generators to convert the heat from decaying radioactive materials into electricity. NASA’s “Icy Moons of Jupiter” project would have demonstrated nuclear fission reactors for space propulsion; it was started a few years ago but terminated due to insufficient funding.

Nuclear fission reactor technology used on earth is mature. With sufficient investment in research and development, practical and safe fission reactors for space propulsion and electrical power could become available in the not-too-distant future.