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Satnews Daily
May 14th, 2010

Galaxy 15 'Zombiesat' Gone Wrong — Will 'Lost' Be Lost?

Galaxy 15 Launch
There has been much exchange of information regarding the report of the communications satellite Galaxy 15 which on April 5, has not responded to ground controls, hence the moniker from some of "zombiesat". After sending between 150,000 and 200,000 commands to the satellite to bring it back into service, Intelsat was forced to scrap its satellite-recovery efforts and to resort, on Monday, to a limited-duration effort to force the satellite to shut down its transponders. This was to be accomplished by sending a stronger series of signals designed to cause Galaxy 15's power system to malfunction and force a shutdown of the satellite's payload.

Washington-headquartered Intelsat foresaw this as a final attempt to shutdown Galaxy 15, which was unsuccessful. Now the satellite is approaching AMC-11. "There is no active testing of the payload," the company said in its Tuesday statement. In fact, this sat has taken up space in the same orbit as another C-band satellite, the AMC-11 spacecraft operated by SES World Skies, which sends cable programming to households across the U.S. (Some have speculated this may cause interference around May 23, which is the when the finale of ABC’s ‘Lost’ is scheduled to air.)

Sending radio signals strong enough to force a satellite to shut down put other spacecraft in the target area in jepardy, which is why Intelsat had only a short window of time to "pulse" Galaxy 15 with signals intended to trigger a failure of its power system. That period lasted about 30 minutes on Monday.

"Intelsat fully coordinated with neighboring operators the timing and the effects of this testing to neighboring spacecraft. It is our current understanding that no SES AMC-11 customers were affected by the disabling attempt," Intelsat said.

SES officials believe they have the resources, including teleport facilities to reroute traffic, required to minimize the problem during this two-week period, but admit that there are no guarantees that there won't be interference to media customers using AMC-11.

From that point on it is forecast that around June 7, the Galaxy 15 will leave the AMC-11 orbital slot, and Intelsat is looking for another opportunity to work the renegade sat at there will be no C-band satellite at the next orbital station of 129 degrees west.

Intelsat has been taking information and advice from other satellite operators and manufacturers that have experience with in-orbit problems.

The timeline looks to Galaxy losing Earth orientation in late July or early August. When this occurs its solar arrays will lose their lock on the sun, subsequently the satellite's batteries will drain, and the satellite will, of its own accord, shut down.