An illustration of NASA’s Relay 1 satellite, the precursor to Relay 2
NASA
A surprising event occurred when a long-dead satellite, NASA’s Relay 2, suddenly emitted a powerful radio pulse that momentarily became the brightest object in the sky. Scientists speculate that this unexpected flash could have been triggered by a rare micrometeorite impact or an incidental spark.
Initially launched in 1964 as an experimental communication tool, NASA’s Relay 2 satellite ceased operation in 1965, with its electronics failing completely by 1967, leaving it as space debris orbiting Earth indefinitely.
Researchers, led by Clancy James from Curtin University in Australia, were puzzled when they detected a brief but intense burst of radio waves emanating from the satellite’s presumed location almost 60 years later.
Utilizing the Australian Square Kilometre Array Pathfinder (ASKAP), a network of 36 radio telescopes in Western Australia, James and his team were scanning the cosmos for fast radio bursts, enigmatic bursts of energy originating from distant galaxies.
On 13 June of the previous year, they picked up a signal that seemed to originate within our Milky Way galaxy. Excited at the prospect of a new cosmic discovery, the scientists soon realized that the signal was in such proximity to Earth that ASKAP could not focus all its telescopes simultaneously, indicating a source within 20,000 kilometers of our planet. The signal was remarkably short-lived, lasting less than 30 nanoseconds, yet it surpassed all other celestial emissions in brightness during that brief period.
Further investigation pinpointed the signal’s origin to the vicinity of the defunct Relay 2 satellite. Given the satellite’s defunct state, the researchers posit that an external event, such as an electrostatic discharge or a micrometeorite impact generating a cloud of charged plasma, likely triggered the powerful radio pulse.
Karen Aplin from the University of Bristol, UK, noted the challenges in distinguishing between the two scenarios based on the radio signal’s characteristics. However, she suggested that monitoring future electrostatic discharges from satellites could be beneficial. This detection could serve as a novel method for evaluating electrostatic discharges in space, particularly with the increasing presence of space debris and the proliferation of small, cost-effective satellites with limited protection against such discharges.
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