Space: Out-of-Control Satellite Threatens Other Spacecraft

[bystander]

Out-of-Control Satellite Threatens Other Nearby Spacecraft
Space.com - 03 May 2010

An adrift Intelsat satellite that stopped communicating with its ground controllers last month remains out of control and has begun moving eastward along the geostationary arc, raising the threat of interference with other satellites in its path, Intelsat and other industry officials said.

In what industry officials called an unprecedented event, Intelsat's Galaxy 15 communications satellite has remained fully "on," with its C-band telecommunications payload still functioning even as it has left its assigned orbital slot of 133 degrees west longitude 36,000 kilometers over the equator.

Galaxy 15 stopped responding to ground controllers on April 5. The satellite's manufacturer, Orbital Sciences Corp. of Virginia, has said an intense solar storm in early April may be to blame. It was launched into space in 2005.
...
On May 3, Intelsat will play what as of Friday appeared to be its last card by blasting Galaxy 15 with a more powerful signal intended not to salvage the satellite, but to force it into a complete shutdown.

That attempt will last about 30 minutes. It will not be repeated, both because a second attempt is viewed as unnecessary — the treatment works or it does not — and because sending out powerful radio frequency signals carries the risk of interfering with other satellites in the area.

Even if the May 3 action succeeds, Galaxy 15 will remain a problem as it continues to wander the geostationary arc. But it is a problem that satellite operators know how to deal with. Industry experts say there are several dozen spacecraft, sometimes called "zombiesats," that for various reasons were not removed from the geostationary highway before failing completely.

Depending on their position at the time of failure, these satellites tend to migrate toward one of two libration points, at 105 degrees west and 75 degrees east. Figures compiled by XL Insurance of New York, an underwriter of space risks, say that more than 160 satellites are gathered at these two points, which Bednarek described as the orbital equivalent of valleys.

[bystander]

Attempt to Shut Down Zombie Satellite Galaxy 15 Fails
Space.com - 05 May 2010

An attempt to shut down the electronics payload of the out-of-control communications satellite Galaxy 15 has failed, leaving the satellite - which ceased responding to ground commands last month - still in its uncontrolled "zombiesat" drift toward orbits occupied by other spacecraft, the satellite's fleet operator Intelsat said Tuesday.

Galaxy 15 is closing in on the geostationary orbital slot occupied by another C-band satellite, the AMC-11 spacecraft operated by SES World Skies, and with its stuck-on communications payload will be in a position to cause potentially severe interference with the SES satellite during a two-week period starting around May 23, according to Intelsat and SES estimates.

The unsuccessful attempt to shut down the so-called "zombiesat" – a satellite industry term for failed satellites in orbit - occurred on Monday.

[bystander]

Galaxy 15 Status Update: Power, Communications, and Control Restored
SpaceRef.com | 28 Dec 2010

On 23 December, the power from the Galaxy 15 battery completely drained during its loss of earth lock and the Baseband Equipment (BBE) command unit reset, as it was designed to do. Shortly thereafter Galaxy 15 began accepting commands and Intelsat engineers began receiving telemetry in our Satellite Operations center. We have placed Galaxy 15 in safe mode, and at this time, we are pleased to report it no longer poses any threat of satellite interference to either neighboring satellites or customer services.

After completing initial diagnostic tests, we will load updated commanding software to the satellite. We expect to relocate the satellite to an Intelsat orbital location where engineers at our Satellite Operations Control Center will initiate extensive in-orbit testing to determine the functionality of every aspect of the spacecraft. We will provide an update through normal sales channels, and MyIntelsat, if and when the satellite recovery mission is successful.

Source and Status Updates: Intelsat