mahar@weitek.UUCP (Mike Mahar) (02/24/88)
Keywords: Are there critical launch windows when a sattalite is to be placed into Clarke orbit? I seem to recall mention of them but never understood why. The relative positions of the launch site and the final parking orbit don't change. Do they?
karn@thumper.bellcore.com (Phil R. Karn) (02/24/88)
The only real restriction on the time you can launch a geostationary satellite has to do with sun-angle restrictions on the spacecraft. You generally want the sun to be perpendicular to the solar arrays during the coast and maneuver phases, and you don't want the satellite tencounter long eclipses during this time. Phil
henry@utzoo.uucp (Henry Spencer) (02/25/88)
> Are there critical launch windows when a sattalite is to be placed into > Clarke orbit? I seem to recall mention of them but never understood > why. The relative positions of the launch site and the final parking > orbit don't change. Do they? No, but the relative position of the Sun does. Most modern solar-powered satellites don't unfold their solar panels fully until they are finished with major maneuvering, because the panel structure is not built for high accelerations. This means that the maneuvering configuration has only limited power available and may not be able to pivot its solar panels the way the operational configuration can. As a result, the maneuvering phase has to maintain favorable sun angles. This can mean quite narrow launch windows. -- Those who do not understand Unix are | Henry Spencer @ U of Toronto Zoology condemned to reinvent it, poorly. | {allegra,ihnp4,decvax,utai}!utzoo!henry