Station-keeping fuel used to raise communications satellite to geosynchronous position
Boeing Satellite Systems (BSS) and International Launch Services (ILS) are trying to determine which of them is responsible for the Space Communications (SCC) Superbird-6 ending up in too low an orbit after launch on 15 April by a Lockheed Martin Atlas IIAS.
The Boeing 601-class communication satellite finally reached its position in geosynchronous orbit with a reduced load of station-keeping fuel after some of the propellant reserve was used to raise its orbit.
It is believed that, after the booster's upper stage placed the satellite into its initial geostationary transfer orbit, a flight program that failed to take into account gravity dropped the geosynchronous transfer orbit perigee to 100km (60 miles) - almost ending the mission with a premature re-entry.
Boeing and SCC were awaiting the scheduled 25 May deployment of the satellite's solar panels to determine whether heating resulting from the low orbit had caused damage to the arrays.
ILS says the satellite was delivered "right on the mark" of orbital data supplied by BSS, with a perigee of 167.1km compared with the mission requirement of 167km, an apogee of 122,343km (requirement 86,882-123,622km) and inclination of 26.25° (requirement 28.1° or less).
BSS says the satellite "had to use up fuel to get to the right orbit, but still has a 12-year operational life". Superbird-6 was handed over to SCC on the ground, the Japanese satellite operator having contracted separately with ILS for the launch.
ILS has added the Atlas V launch of SES Americom's AMC 16 to its manifest for late this year. The Lockheed Martin A2100-series spacecraft was scheduled for a 2005 flight on an ILS Proton, and will be the fifth SES Americom satellite to be launched by ILS this year, after AMC 10 in February and AMC 11 in May, both by Atlas, and AMC 15 and Worldsat 2, previously AMC 12, both now manifested on Protons.TIM FURNISS / LONDON
Source: Flight International
