Believed to have been hit by a solar storm in April, a commercial satellite called Galaxy 15 is drifting out of its original orbit, raising concerns about threats to other satellites. It's been dubbed a "zombie satellite" because the solar storm essentially scrambled its brain by frying the electronics.
Zombie satellites are nothing new, but what makes the case of Galaxy 15 unique is that the Intelsat-owned satellite isn't responding to commands from Earth, yet still is transmitting a signal. That makes it dangerous -- not so much because it risks running into other satellites (while possible, the chances of that are small), but because it can interfere with their signals.
"If Galaxy 15 drifts too close to other satellites, it can steal their signal, thereby interrupting other vendors' services to customers on Earth," explains Ian O'Neill, writing at Discovery News. "That's not too good for business, hence the increasingly desperate attempts to 'kill' the satellite's power."
According to Intelsat officials, engineers earlier this week analyzed various tests that they might be able to perform on the satellite, and selected the one they thought had the best chance of working: "pulsing" the satellite with signals to try to shut it off.
The experiment, however, didn't work.
The next chance for stopping the zombie satellite will be when it reaches an orbital slot of 129 degrees west longitude, which is free of other satellites, some weeks from now. "We do not have an additional specific technical attempt identified at this time, but we will not give up and expect to have other options to pursue at that time," an Intelsat official told AOL News.
As for heading off such mishaps in the future, the leading defense -- "hardening" satellites to protect them from the effects of solar storms -- isn't always a foolproof solution. "Most satellites are radiation hardened, but hardening is a continuum," Yousaf Butt, a physicist in the High-Energy Astrophysics Division at the Harvard-Smithsonian Center for Astrophysics, tells AOL News. "One can always try to make a satellite more radiation-hardened, but it is a commercial trade-off where to draw the line."