NASA satellite 'dead' for 57 years sends mysterious signal to Earth

NASA's Relay-2 mission launched on January 21, 1964, two years after Relay-1, and the pair were tasked with mapping the Van Allen radiation belts. The Relay-2 satellite operated until June 1967, when its transmitters stopped responding. That was until last year, on June 13, when the Australian Square Kilometer Array Pathfinder detected a fast radio burst (FRB) that lasted less than 30 nanoseconds.

“It was an incredibly powerful radio burst that completely overpowered everything else in the sky for a very short period of time,” Clancy James, a researcher at Curtin University, told New Scientist . Originally, researchers assumed the signal came from a distant object in the universe. Now, a comprehensive investigation reveals that Relay-2 was the source.

FRBs are powerful but short bursts of energy that come from deep space and can release so much energy that they can outshine an entire galaxy. The signal in question was unusually clean and well-defined.

The explanation for why Relay-2 suddenly emitted this signal is not yet known. Scientists believe that the satellite may have accumulated enough electricity over the years and suddenly produced the discharge. Another hypothesis being considered is that Relay-2 may have been hit by a micrometeorite or other object in orbit that resulted in the release of a small cloud of plasma.