The Use of Ion Thrusters for Orbit Raising.
ROYAL AIRCRAFT ESTABLISHMENT FARNBOROUGH (ENGLAND)
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Earlier analytical results for changing the orbital altitude of a spacecraft, using a tangentially thrusting electric propulsion system, have been employed to confirm that the mass of propellant required to attain a geostationary orbit is only a very small fraction of the initial mass of the satellite. However, such an orbit transfer technique requires a relatively long period of time compared with chemical propulsion, typically 100 to 300 days, and, for spacecraft masses of 1000 kg or more, multi-kW solar arrays are necessary. Unfortunately, the long transfer time also leads to a significant degradation of the power produced by these solar arrays, owing to the impact on them of energetic particles while traversing the earths radiation belts. Nevertheless, it is concluded that this technique for manoeuvring a satellite into synchronous orbit can offer attractive economic benefits for two broad classes of spacecraft. These are relatively small satellites, of 1000 kg or less, for which a dedicated ion thruster system can be advocated, and much larger devices, for which a reusable solar electric tug vehicle having its own solar arrays would be appropriate. In the former case, a payload ratio of about 0.7 could be achieved, with a transfer time of 150 days, and two or three spacecraft could be launched on a single Ariane vehicle. Author
- Electric and Ion Propulsion
- Unmanned Spacecraft