| 摘要 |
Systems and methods for launching a satellite into orbit that optimize the mass of the satellite delivered into orbit. A satellite carrying one or more chemical propulsion devices and one or more electric propulsion devices is launched into a transfer orbit using a launch vehicle. In one embodiment, a selected chemical propulsion device is fired to raise the orbit of the satellite from the transfer orbit to an intermediate orbit. One or more electric propulsion device is fired to raise the orbit of the satellite from the intermediate orbit to final geosynchronous orbit and the one or more electric propulsion device is throttled to produce variable thrust levels so as to operate at all optimum specific impulse level to optimize the mass of the satellite delivered into orbit. In another embodiment, the electric propulsion device may deliver the satellite into a near-geosynchronous orbit instead of final geosynchronous orbit. In this case, a selected chemical propulsion device is fired to place the satellite in its final orbit. In yet another embodiment, the launch vehicle may be used to deliver the satellite into the intermediate starting orbit after which the electric propulsion device is used to achieve final orbit. In this case, the transfer orbit raising step is omitted.
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