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Geostationary GPS Satellite Galaxy 15 Out of Control
Bruce Perens writes "The Galaxy 15 commercial satellite has not responded to commands since solar flares fried its CPU in April, and it won't turn off. Intelsat controllers moved all commercial payloads to other birds except for WAAS, a system that adds accuracy to GPS for landing aircraft and finding wayward geocaches. Since the satellite runs in 'bent pipe' mode, amplifying wide bands of RF that are beamed up to it, it is likely to interfere with other satellites as it crosses their orbital slots on its way to an earth-sun Lagrange point, the natural final destination of a geostationary satellite without maneuvering power." (More below.)
Bruce continues: "The only payload that is still deliberately active on the satellite is its WAAS repeater. An attempt to overload the satellite and shut it down on May 3 caused a Notice to Airmen regarding the unavailability of WAAS for an hour. Unsaid is what will happen to WAAS, and for how long, when the satellite eventually loses its sun-pointing capability, expected later this year, and stops repeating the GPS correction signal. Other satellites can be moved into Galaxy 15's orbital slot, but it is yet unannounced whether the candidates bear the WAAS payload."
In 1998, Galaxy IV blew out, which controlled commercial communications for a metric assload of services (including my former employer's dealership communications network, FordStar). I (and every other remote admin) got a $50 bounty per dish that we hurriedly re-pointed to a different satellite. Cleaned the whole thing up across the global network (four continents) in less than three weeks.
I'm fairly sure that cable TV, which has more sats on tap and relatively less dishes to re-position (and nobody has to crawl on top of a zillion roofs with a wrench and a compass in hand), could likely recover in very short order - probably hours.
That said, there's always the danger of a chain reaction (after all, there's a LOT of satellites in geosync orbit) - if not at this time, then certainly in the coming future, as the numbers continue to increase.
Quo usque tandem abutere, Nimbus, patientia nostra?
Light doesn't just illuminate something. It has pressure. If you illuminate a satellite from the proper angle with less than the energy required to blow it apart, for long enough, you can change its orbit.
Bruce Perens.
It has something to do with the mass of the Earth. These points line up pretty well with the Rocky Mountains and the Himalayas. These areas are known as gravity wells and all Geo satellites try to drift there. As operational satellites drift, they are command back into their orbital slot by their operators. Some satellite operators will purposely position their satellites at the wells as there is less fuel required to keep them in their orbital. Dead satellites drift towards the closet well, slingshot past them, and then come back. Occasionally they will swing back and forth between the two wells. It takes several months to swing back and forth. The satellites also gain inclination over time (15 years) before they hit a certain orbital point and then their inclination drifts back down to zero, and repeat. The inclination drift is said to be due to the Moon, however, it's tied the the satellites Right Ascension of the Ascending Node (RAAN), something that's independent of the Moon. Regardless, over time these satellites that die on the "Geo-belt" only really cross the operational satellites twice a day because of their inclination. US law requires satellite operators to dispose of their GEO satellites into a graveyard orbit before they die, but you can't really do that when it stops responding. http://en.wikipedia.org/wiki/Graveyard_orbit