Pat Greenhouse / Boston Globe via Getty Images
There are more than 2,000 active satellites orbiting the Earth. At the end of their useful life, many of them will simply burn up on re-entry into the atmosphere. But some will continue to run as “zombie” satellites – neither alive nor quite dead.
“Most zombie satellites are satellites that are no longer under human control, or that have failed to some extent,” says Scott Tilley.
Tilley, an amateur radio operator living in Canada, has a passion to track them down.
In 2018, he found a signal from a NASA probe called IMAGE that the space agency had lost track of in 2005. With Tilley’s help, NASA was able to reestablish contact.
But he’s been hunting down zombies even older than IMAGE.
“The oldest I have seen is Transit 5B-5. And it was launched in 1965, “he says, referring to a US Navy nuclear-powered navigation satellite that still circles the Earth in a polar orbit, long forgotten by all except from a few amateurs interested in hearing it. “to sing” as it passes over.
Recently, Tilley became interested in a communications satellite he believed to be still alive – or at least among the living dead. LES-5, built by the Massachusetts Institute of Technology’s Lincoln Laboratory, was launched in 1967.
Tilley was inspired by another amateur who in 2016 had found LES-1, an earlier satellite built by the same laboratory. What intrigued him about LES-5 was that if it still worked, it could be the oldest working satellite still in geostationary orbit.
While browsing the internet he found an article describing the radio frequency that LES-5, an experimental UHF military communications satellite, should work on – if he was still alive. So he decided to take a look.
“It required building an antenna, erecting a new structure to support it. Preamps, filters, stuff that takes time to put together and assemble,” he says.
“When you have a family and a busy business, you don’t really have a lot of time for it,” he says.
But then came the COVID-19 pandemic.
Well here is what appears to be a new ZOMBIE SAT!
LES-5 [2866, 1967-066E] in a GEO cemetery orbit.
Confirmation will take place at ~ 0445 UTC tonight when the satellite is expected to pass through the eclipse.
If so, this is certainly the oldest transmitting GEOsat I know of. pic.twitter.com/QFSRb5bT1I
– Scott Tilley (@ coastal8049) March 25, 2020
British Columbia, where Tilley lives, was in lockdown. Like many of us, Tilley suddenly had some free time. He used it to search for LES-5, and on March 24, it hit the amateur radio equivalent of paid dirt.
He has since taken additional measures.
“The reason this one is quite intriguing is that its telemetry beacon is still working,” says Tilley.
In other words, says Tilley, even though the satellite was supposed to shut down in 1972, it’s still working. As long as the solar panels are in the sun, the satellite radio will continue to operate. Tilley thinks it might even be possible to send commands to the satellite.
The MIT lab that built the LES-5 is still doing a lot of work on classified projects for the military. NPR contacted their press office to ask if anyone could say more about LES-5 and if they could really still receive orders.
But after repeated requests, the Lincoln Laboratory ultimately responded with a “no comment.”
It seems even a 50-year-old zombie satellite may still have secrets.