b'Analysis of MarsResearchers enable faster and safer exploration of the outer solar system by Perseverance Multi- proving the feasibility of nuclear propulsion and electricity generation.mission RadioisotopicT here are two primary needs for nuclear power in space: propulsion and electrical power. This project included five integrated studies for using a Thermoelectric Generatorreactor for nuclear thermal propulsion for short burns (about 30 minutes) Neutron/Gammaat high power (~500 MWth) and lower power use (about 700 kWe) for about 400 days between the burns. For nuclear thermal propulsion, hydrogen flows first Spectrum for use onthrough the structural cooling channels where the temperature increases from Dragonfly and Nuclear20 K to about 800 K followed by flow through the reactor fuel itself, where the temperature increases from 800 K to about 2800 K. During the low power electrical Thermal Propulsiongenerating phase, the structural cooling channels carry a helium and xenon mixture Materials Modeling in a closed Brayton cycle to produce about 200 kWe.Specific research tasks during the project included:Describing the Bimodal Epithermal Astro-nuclear Reactor conceptCompleting a thermal structural analysis of flow tube and fuel used in the nuclear thermal propulsion reactorDetermining the hydrogen diffusion in the flow tube of nuclear thermal PROJECT NUMBER:propulsion system22P1073-001 Calculating materials thermophysical properties of uranium zirconium carbide TOTAL APPROVED AMOUNT:(U.Zr.C) using density functional theory analyses$275,000 over 1 year Studying the tungsten-184 enrichment to avoid the high neutron absorption of tungsten-186PRINCIPAL INVESTIGATOR: Stephen Johnson The Monte Carlo burnup analysis of the bimodal reactoralternating propulsive and electrical burnsindicates that reactor could power five missions from Earth CO-INVESTIGATORS: to Mars and return, where the hydrogen propellant would be replenished on each Stephen Herring, Center forreturn to low Earth orbit. Upon the completion of the five missions, the controlSpace Nuclear Research drums would be removed and replaced by control rods in the same locations. The Brad Kirkwood, Consultant modified reactor would be emplaced in the lunar or Martian regolith and would COLLABORATOR: produce 700 kWe for about 25 years. Each mission includes:NASA Marshall Space Flight Center 30-minute trans-Mars injection 197-day Earth to Mars transfer23-minute Mars orbit insertion555-day Mars parking orbit20-minute trans-Earth injection198-day Mars to Earth transfer15-minute Earth orbit insertion610-day Earth parking orbit50'