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 (LEO), inclined to the equator, to a circular geosynchronous Earth orbit (GEO) with no inclination. The principle is to minimize the propulsive-mass cost for a continuously thrusting vehicle with the capability for multiple on-off thrusting cycles. The analysis was conducted for a large range of initial accelerations, and it was found that the method is best used to bridge the gap between very low-thrust transfers and high-thrust, impulsive transfers. The simulation of a LEO-GEO transfer showed that the results varied from 1% over the optimal cost for a high-thrust transfer, to 2.5% over the optimal cost for an intermediate-thrust transfer, to 0.3% over the cost of a low-thrust, spiral transfer. This makes this technique a good first estimate algorithm for the entire range of high- to low-thrust transfers.