Assessment of an SP-100 bi-modal propulsion and power system

The attractiveness of using the SP‐100 space nuclear power system for both electric power production and direct thermal propulsion is discussed. A conceptual modification to the SP‐100 generic flight system that uses its hot, primary coolant to directly heat hydrogen propellant is presented. An analytical model of the system and its orbital‐mechanical behavior is presented and used to assess the benefits of a number of orbital transfer missions. Both a 500 kW and a 2.4 MW system are assessed. Preliminary results indicate that for LEO‐to‐GEO transfers, the SP‐100 bi‐modal system offers a 100 % increase in payload over conventional chemical‐only propulsion systems with transfer times on the order of days.