In-Space Deployment Options for Large Space Solar Power Satellites

Abstract

This research was performed at the Space Systems Design Lab at the Georgia Institute of Technology, Atlanta, GA, with the charter of identifying economically attractive candidate space transfer vehicle systems for ferrying components of Space Solar Power (SSP) satellites from Low Earth Orbit (LEO) to Geostationary Earth Orbit (GEO). An aggressive price goal of only $400/kg of payload was established in order to control the cost of transportation for the SSP satellite developer.

A multi-step decision process was employed to down-select from a large number of candidate systems to four. The final four concepts were Nuclear Thermal Rocket (NTR), Solar Thermal Rocket (STR), a rotating tether, and Solar Electric Propulsion (SEP). Additional concepts considered were Dual-Mode (Chemical/SEP) and All-Chemical.

Results show that the most economical concept is one which is highly reusable, has a short turn-around time, a long vehicle life, and small propellant requirements. These characteristics result in a low fleet size and therefore lower debt requirements. These characteristics also lower the Initial Mass in Low Earth Orbit (IMLEO) and therefore lower deployment costs. The goal of $400/kg, or 2.5cents/kW-hr, for in-space transportation costs is very aggressive and difficult to achieve.