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Mysterious "Dead" Satellite Sends Powerful Signal to Earth After Decades
Scientists received a mysterious radio pulse that came from a satellite that had been dead for decades. The signal was so powerful that for a moment it outshone all other objects in the sky, New Scientist reported.
The radio pulse was blasted from a defunct satellite, Relay 2, which was a NASA experimental communications satellite launched in 1964.
It was part of the Relay programme, which consisted of two satellites, Relay 1 and Relay 2, designed to test communications in medium Earth orbit. Both satellites were funded by NASA.
The US-based space agency stopped using it in 1965, and the technical and electronic devices stopped working altogether by 1967.
Last year on June 13, scientists using the Australian Square Kilometre Array Pathfinder (ASKAP) detected a small but powerful flash that lasted less than 30 nanoseconds.
Clancy James at Curtin University in Australia and his colleagues were shocked as the signal came from our galaxy.
"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," says 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," Clancy added.
Scientists studied the source and found that the signal came from within 20,000km of Earth. After comparing it with the locations of known satellites, they found that the pulse came from the Relay 2 satellite.
As the satellite has been dead for nearly six decades, scientists believe that the signal must have come from an external factor, such as an electrostatic discharge or a micrometeorite.
Either it was a spark-like flash that originated from a build-up of electricity, or it was a plasma discharge following a micrometeoroid impact.
"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," Karen Aplin at the University of Bristol, UK, said as quoted.
The research, whose preprint is available on arXiv, has been accepted for publication in The Astrophysical Journal.
