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SES Astra: Revizyonlar arasındaki fark

[kontrol edilmemiş revizyon][kontrol edilmemiş revizyon]
The satellites are launched by [[Arianespace]] [[Ariane (rocket)|rockets]] from [[Kourou]], [[French Guiana]] or [[International Launch Services]] [[Proton rocket]]s from [[Baikonur Cosmodrome|Baikonur]], [[Kazakhstan]]. The satellites are launched into an elliptical "temporary transfer orbit" from where they use onboard propulsion to reach their final circular [[geostationary orbit]]s, at nearly 36,000 km altitude. Proton rockets fitted with a fourth stage propulsion unit are capable of launching the satellites several thousand kilometres higher (at the closest point of the elliptical orbit) than Ariane rockets. As a result most satellites launched in this way have to use less fuel to reach their geostationary orbit, increasing their lifetime.
 
===FailuresBaşarısızlıklar===
[[Astra 1K]], the largest commercial communications satellite ever built at the time, was ordered by SES-Astra in 1997. It was launched by Proton rocket on [[November 26]] [[2002]]. The rocket lifted off as planned and reached its [[parking orbit]] at which point the final stage of the rocket was to initiate a second burn to transfer the satellite to its geostationary orbit. This did not occur and the satellite was released into the parking orbit, making it unusable. The only way to recover the satellite would have been the use of a [[Space Shuttle]], however this was rejected. On [[December 10]] [[2002]] SES Astra instructed Alcatel Space (the manufacturer) and the French Space Agency [[CNES]] to deorbit the satellite, it broke up on re-entry over the [[Pacific Ocean]].
 
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