Russian experience in development of nuclear power systems and nuclear thermal propulsion systems of the first generation as the basis for development of advanced power and propulsion complexes for peaceful exploration of near and deep space

Reactor-based nuclear power systems found a certain niche in space programs in the 20th century. Russian BUK space thermoelectric systems successfully operated in Cosmos series spacecraft. Two Russian TOPAZ space thermionic systems were in 1987 successfully tested during 0.5 year and 1 year in combination with electric thrusters in Cosmos-1818 and Cosmos-1876 spacecraft. The Russian ENISEY space nuclear power system (SNPS) underwent a complete cycle of ground testing, including 6 nuclear power tests for a 1.5-year life. Extensive R&D efforts were undertaken in Russia to build nuclear thermal propulsion (NTP) systems. The work on SNPS and NTP performed in Russia provides a basis for further activities on utilization of nuclear power in space, such as building communication and surveillance systems, Lunar base and Mars missions, exploration of Jupiter Moons. These activities rely on establishment of a technology base in the 21 century and building powerful power and propulsion complexes capable of delivering 2 to 3 times heavier payloads from radiation-safe near-earth orbits to high-power orbits and providing spacecraft equipment with electric power at 50 to 100 and more kW during a long term (up to 10 years). The basic requirement of these activities is to ensure nuclear and radiation safety of space nuclear power and propulsion systems (SNPPS) for the Earth population. The paper summarizes Russian experience in development of the first generation of nuclear power systems with direct (thermoelectric and thermionic) energy conversion. Based on the accumulated experience, research activities are being pursued in Russia to develop components of higher power (50-400 kWe) and longer life (up to 5-7 years aid more) power and propulsion complexes capable of providing thrust for spacecraft transfer from a radiation-safe near-earth orbit to a geostationary orbit and into deep space, and generating power for long-term supply of spacecraft systems. The paper presents main parameters of the ROMASHKA reactor-converter, BUK, TOPAZ and ENISEY SNPS developed in Russia at the first stage of activities, compares NTP parameters achieved in the USSR and in the US. Based on the performed R&D and accumulated experience, the paper presents design parameters of advanced 50 to 400 kWe power and propulsion systems with electric thrusters and thermionic conversion, and of those using NTP for thrust generation and closed gas turbine system for electricity generation for spacecraft power supply. The paper expresses an opinion that international cooperation is required to develop advanced SNPS for peaceful uses in near and deep space.