Developing a Nuclear Fission Fragment Rocket Engine for Interstellar Missions

Thursday - November 16 2023, 02:17 UTC - 1 year ago

The NASA NIAC project is creating a nuclear fission fragment rocket engine which is exponentially more propellent efficient than current rocket engines, allowing for travel times to Mars of 90 days, and enabling interstellar rockets with speeds up to 10% of the speed of light. The mission concept includes deploying an array of telescopes with baseline separations of up to 10,000 kilometres in order to build an image of a habitable exoplanet with enough resolution to see its surface features and signs of habitability.

A nuclear fission fragment rocket engine (FFRE) that is exponentially more propellent efficient than rocket engines currently used to power today’s space vehicles and could eventually achieve very high specific impulse (>100,000 sec) at high power density (>kW/kg). A new NASA NIAC (NASA Innovative Advanced Concepts) project is creating a buildable near term design for a nuclear fission fragment rocket. It would enable manned mission to Mars with 90 day travel times. The fission fragment system would give experience in a technology which could eventually enable interstellar rockets with speeds of 10% of the speed of light.

Current proposed designs for Fission Fragment Rocket Engines are prohibitively massive, have significant thermal constraints, or require implementing complex designs, such as dusty plasma levitation, which limits the near-term viability. Researchers propose to develop a small prototype low-density nuclear reactor core and convert the nuclear energy stored in a fissile material into a high velocity rocket exhaust and electrical power for spacecraft payloads.

The key improvements over previous concepts are: .

1. Embed the fissile fuel particles in an ultra-low density aerogel matrix to achieve a critical mass assembly .

2. Utilize recent breakthroughs in high field, high temperature superconducting magnets to constrain fission fragment trajectories between moderator elements to minimize reactor mass.

The aerogel matrix and high magnetic field (B>20T) allows for fission fragments to escape the core while increasing conductive and radiative heat loss from the individual fuel particles. NIAC work will provide detailed mission analysis of fast transit to SGL for direct imaging and high-resolution spectroscopy of a habitable exoplanet at a distance of up to 100 light years. The FFRE propulsion system could provide delta-V to reach the SGL in less than 15yrs and provide the slowdown and maneuvering capability at SGL. The telescopes would act as a single pixel detector while traversing the Einstein Ring region, building an image of the exoplanet with enough resolution to see its surface features and signs of habitability.