Preliminary Design of a Very-Low-Thrust Geostationary Transfer Orbit to Sun-Synchronous Orbit Small Satellite Transfer

Preliminary Design of a Very-Low-Thrust Geostationary Transfer Orbit to Sun-Synchronous Orbit Small Satellite Transfer

Small satellites have proven their viability for conducting meaningful missions at a fraction of the cost of larger satellites. Correspondingly, the demand for small satellite missions is increasing as is the need for more sophisticated low-cost satellites. To enable these more advanced missions, this paper analyzes the feasibility of using a low-thrust propulsion system to transfer to a mission orbit from a readily available launch opportunity. Speci¯cally, a geosynchronous transfer orbit (GTO) launch to a sun-synchronous orbit (SSO) small satellite trajectory is examined. The transfer from GTO to SSO orbit is designed using a direct optimization method. Due to the very low thrust levels, the transfer time to obtain the operational orbit is long (»360 days) with numerous orbit revolutions (1400). To solve this extremely large optimization problem, a new multiple-orbit thrust parameterization strategy was developed. This new method has proven to be very robust and capable of handling large complex problems. Preliminary trajectory design shows that mission feasibility for a 100 kg small satellite GTO-SSO transfer greatly depends on the propulsion system's speci¯c impulse.