Astronomers thought a mysterious radio burst came from deep space. It was actually a dead NASA satellite

A fast radio burst (FRB) has turned out to be an emission from a long-dead NASA satellite called Relay 2 .

The now-discounted FRB or "pseudo-FRB" was detected by the Australian Square Kilometer Array Pathfinder ( ASKAP ) in June 2024 as this telescope scanned the sky over the southern hemisphere.

It was remarkable because this burst of radio waves lasted less than 30 nanoseconds, much shorter than most FRBs, and yet it was strong enough to drown out other signals from the sky.

The team is certain that this "pseudo-FRB" signal wasn't an intentional emission.

Relay 2 has been inoperative for 58 years , and even when it was working, its transmission signal was not capable of generating such short-lived radio pulses.

One theory is electrostatic discharge ( ESD ) a build-up of electricity that results in a spark-like flash.

Another is that a micrometeorite had struck the satellite and produced a cloud of charged plasma, right as ASKAP was observing the part of sky it was in.

ESD is a huge problem for satellites, and can cause all kinds of damage.

Radio telescopes could be particularly useful for detecting ESD .

The team's research is published on the paper repository site arXiv.com.