Astronomers are puzzled by a strong burst of radio waves traced back to a NASA satellite that had been inactive since the 1960s
By Alex Wilkins
20 June 2025
An illustration of NASA’s Relay 1 satellite, the precursor to Relay 2
NASA
A satellite that had been dead for decades suddenly blasted out a powerful radio pulse that briefly outshone every other object in the sky. Astronomers think the flash may have been caused by a freak micrometeorite impact or a random spark.
NASA’s Relay 2 satellite was one of the first functioning satellites, launched in 1964 as an experimental communications device. NASA stopped using it the following year, however, and the satellite’s onboard electronics stopped working altogether by 1967, leaving the dead metal hull to orbit Earth indefinitely.
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So Clancy James at Curtin University in Australia and his colleagues were perplexed when, nearly 60 years later, they detected a brief, powerful burst of radio waves coming from the satellite’s apparent location.
James and his team were scanning the sky with the Australian Square Kilometre Array Pathfinder (ASKAP), an array of 36 radio telescopes in Western Australia, for signs of fast radio bursts, mysterious pulses of radiation that come from other galaxies.
On 13 June last year, they saw a signal that seemed to be coming from within 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.