Analysis of Orbit Transfer Vehicles for GPS (Global Positioning System) Block 3 Satellites

摘要

The overall objective of this research was to determine the feasibility and the cost optimum system for using electric OTVs to move Block 3 GPS satellites from LEO to a 10,900 nm orbit. For the EOTV, the propulsion systems considered were present and 1990's technology ion engines using mercury, xenon or argon for a propellant. There were two power sources evaluated, a 100 KW nuclear reactor and solar arrays. A systems cost model which combines payload, power source, trajectory, and earth-to-LEO launch parameters with algorithms characterizing the electric propulsion system was used. The goal was to find the least costly systems which had a triptime equal to or less than 90 days. These systems were than compared with the PAM D-II, CENTAUR-G, and IUS in terms of total deployment costs for 28 GPS satellites launched at a rate of four per year for seven years. The studies found that a reusable EOTV with 12 mercury ion engines powered by gallium arsenide concentrator arrays could perform the mission for 42% of the ocst of the cheapest chemical system. The nuclear powered EOTV, while less costly than the chemical systems, was not as competitive as the solar EOTV. The weight of the nuclear reactor and its heat radiators required the use of 37 engines resulting in higher costs for the system.