DESIGNING CONTINUOUS-THRUST LOW-EARTH-ORBIT TO GEOSYNCHRONOUS-EARTH-ORBIT TRANSFERS

This paper examines a method that can be used to transfer a spacecraft from a circular low Earth orbit (LEG), inclined to the equator, to a circular geosynchronous Earth orbit (GEO) with no inclination. The pri nciple is to minimize the propulsive-mass cost for a continuously thru sting vehicle with the capability for multiple on-off thrusting cycles . The analysis was conducted for a large range of initial acceleration s, and it was found that the method is best used to bridge the gap bet ween very low-thrust transfers and high-thrust, impulsive transfers. T he simulation of a LEO-GEO transfer showed that the results varied fro m 1% over the optimal cost for a high-thrust transfer, to 2.5% over th e optimal cost for an intermediate-thrust transfer, to 0.3% over the c ost of a few-thrust, spiral transfer. This makes this technique a good first estimate algorithm for the entire range of high- to low-thrust transfers.