Scientists have received a powerful radio signal from Relay 2, a satellite that stopped working nearly 60 years ago. The strange flash came from the old NASA satellite, which was launched in 1964 and last used in 1965.

Relay 2 was one of two satellites launched as part of NASA’s Relay programme. These satellites were created to test how communication worked in medium Earth orbit. However, after just a short time in use, NASA stopped using Relay 2, and all its systems were believed to have fully shut down by 1967.

So, when scientists recently picked up a strong signal from the satellite, it came as a complete surprise.

On June 13 last year, researchers using the Australian Square Kilometre Array Pathfinder (ASKAP) caught a short but extremely bright radio flash. It lasted for less than 30 nanoseconds—that’s faster than a blink.

The team, led by Clancy James at Curtin University in Australia, was stunned.

"If it's nearby, we can study it through optical telescopes really easily, so we got all excited, thinking maybe we'd discovered a new pulsar or some other object," said Clancy, as quoted by New Scientist.

"This was an incredibly powerful radio pulse that vastly outshone everything else in the sky for a very short amount of time," he added.

After carefully checking the source, scientists found that the signal came from just 20,000 kilometers above Earth, which is within our satellite zone. They compared this location to satellite data and discovered the flash came from Relay 2.

Since the satellite has been inactive for decades, researchers don’t believe the signal came from the satellite’s original systems.

Scientists say the signal might have come from something that happened to the satellite, not from it.

Two possible causes are being considered:

  • A build-up of static electricity that suddenly discharged, like a spark

  • A micrometeorite hits the satellite, causing a quick burst of plasma

"In a world where there is a lot of space debris and there are more small, low-cost satellites with limited protection from electrostatic discharge (ESD), this radio detection may ultimately offer a new technique to evaluate electrostatic discharges in space," said Karen Aplin from the University of Bristol in the UK.

The research has been shared on arXiv and will soon be published in the Astrophysical Journal. It could help scientists better understand how space junk and electrical discharges affect satellites.