SP-100

SP-100 — Space Nuclear Reactor Program

Program Overview SP-100 was a tri-agency program (DOE/NASA/SDIO) established in 1983 to develop a 100 kilowatt-electric (kWe) space nuclear reactor power system. The program was designed to provide reliable, long-duration electrical power for space-based assets including SDI (Strategic Defense Initiative) components, space-based radar, and deep space missions.

Strategic Relevance SP-100 is the foundational U.S. space nuclear power program. It established the technology base for all subsequent U.S. space reactor efforts, including Kilopower/KRUSTY and the nuclear thermal propulsion programs (Timberwind, DRACO). The program's cancellation in 1994 coincided with the end of SDIO, demonstrating the pattern of defense-driven nuclear space programs being cancelled when their primary military justification disappears.

Key Details

• Tri-agency: DOE, NASA, SDIO (later BMDO)
• 100 kWe reactor design using uranium nitride fuel
• Lithium-cooled fast reactor with thermoelectric conversion
• Cancelled 1994 with SDIO dissolution
• Technology base for Kilopower/KRUSTY (2015-2018)
• Parallel to classified Timberwind NTP program (1987-1992)

Connection to the Three-Track Architecture SP-100 represents the White Track's space nuclear power foundation. Its cancellation and the later revival of space nuclear technology through Kilopower/KRUSTY demonstrates the cyclical pattern of nuclear space programs. The parallel classified Timberwind program (Black Track) shows how the same technology base exists in both tracks simultaneously.