|
| trans_band = 28 G/H band (IEEE C band) 16 J band (IEEE Ku band) | trans_frequency = | trans_bandwidth = | trans_capacity = | trans_coverage = | trans_TWTA = | trans_EIRP = | trans_HPBW = }} PAS-22, previously known as AsiaSat 3 and then HGS-1, was a geosynchronous communications satellite which was salvaged from an unusable geosynchronous transfer orbit by means of the Moon's gravity. == Launch == AsiaSat 3 was launched by AsiaSat Ltd of Hong Kong to provide communications and television services in Asia by a Proton booster on 24 December 1997, destined for an orbit slot at 105.5° E. However, a failure of the Blok DM3 fourth stage left it stranded in a highly inclined (51 degrees) and elliptical orbit, although still fully functional. It was declared a total loss by its insurers. The satellite was transferred to Hughes Global Services, Inc., with an agreement to share any profits with the insurers. Edward Belbruno and Rex Ridenoure heard about the problem and proposed a 3-5 month low energy transfer trajectory that would swing past the moon and leave the satellite in geostationary orbit around the earth. Hughes had no ability to track the satellite at such a distance, and considered this trajectory concept unworkable. Instead, Hughes used an Apollo-style free return trajectory that required only a few days to complete, a trajectory designed and subsequently patented〔Salvatore, Jeremiah O., and Ocampo Cesar A. (Assignee: Hughes Electronics Corporation) U.S. Patent 6,116,545, "Free return lunar flyby transfer method for geosynchronous satellites," Filed April 9, 1998.〕〔Salvatore, Jeremiah O. and Ocampo, Cesar A. (Assignee: Hughes Electronics Corporation) U.S. Patent 6,149,103, "Free return lunar flyby transfer method for geosynchronous satellites having multiple perilune stages," filed May 15, 1998.〕 by Hughes Chief Technologist Jerry Salvatore.〔J. Fisher, ("AsiaSat Rescue: The Real Story, Part 1" ), Hughes, July 8, 2013 (accessed 10 December 2014).〕 This maneuver removed only 40 degrees of orbital inclination and left the satellite in a geosynchronous orbit, whereas the Belbruno maneuver would have removed all 51 degrees of inclination and left it in geostationary orbit.〔(【引用サイトリンク】title=Hughes Goes to Moon to Salvage Satellite: First Commercial Lunar Mission. )〕 Although Hughes did not end up using the low-energy transfer trajectory, the insight to use a lunar swingby was key to the spacecraft rescue. According to Ocampo, Hughes had not considered this option until it was contacted by Ridenoure,〔(【引用サイトリンク】title=New Book Reveals How Engineers Saved Hughes Satellite on Christmas Day 1997 )〕 although the Hughes engineers involved in the lunar flyby operations have stated that they were already working on the lunar swingby mission design before being contacted by him.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「PAS-22」の詳細全文を読む スポンサード リンク
|