A Comparison of Nuclear and Chemical Propulsion Upper-Stage and Launch Systems for LEO to GEO Orbital Transfers

Comparisons are given between various launch vehicles, transfer vehicles, and propulsion methods to launch satellites into low Earth orbital parking orbits and then into a final geosynchronous orbit. The studies indicate that a Thermionic Space Nuclear Power System (TI-SNPS) can have significant advantages over solar array power systems for both orbital transfer capabilities and mission applications. Also, by utilizing a relatively inexpensive Atlas IIAS launch vehicle, a particular TI-SNPS hybrid design with a specific impulse of 950 sec can place a satellite weighing 3,511 kg into GEO orbit, as compared to only a corresponding 1,104 kg satellite capability when using conventional chemical propulsion techniques.