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Astronomers detect pulse from satellite that has been dead for decades
PERTH, Australia - Astronomers in Australia believe they have detected a rare radio emission from a satellite that hasn't been heard from in decades.
According to the team operating the Australian Square Kilometre Array Pathfinder, a brief burst of energy from NASA's Relay-2 satellite was detected on June 13, 2024, lasting just 30 nanoseconds — an incredibly short duration.
NASA originally launched the communication satellite from Cape Canaveral, Florida, in January 1964.
Relay-2 was intended to support communications and assist with mapping radiation belts around Earth, but the satellite began losing transponders in 1966 and suffered a full communications failure on June 9, 1967.
So, what caused this sudden signal to reach Earth nearly 60 years later? Scientists have offered a few possibilities.
"We consider an electrostatic discharge (ESD) or plasma discharge following a micrometeoroid impact to be plausible explanations for the burst," researchers wrote in a recently released study.
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The mysterious occurrence is not the first time a defunct satellite has emitted a surprising signal.
In 2012, amateur radio operators picked up a pulse from the United States Air Force's Lincoln Experimental Satellite, known as LES-1.
That satellite became inactive in 1967, but experts believe its mode of failure, combined with its orbit, allowed it to intermittently transmit signals when its solar-powered batteries were properly aligned with the Sun.
Similar events occurred in 2002 and 2010, but occurrences of satellites suddenly showing signs of life are relatively rare.
Satellites that unexpectedly come back to life after being declared inoperative are often dubbed "zombie satellites."
The Natural History Museum in London estimates that around 2,000 active satellites are currently orbiting Earth, along with more than 3,000 defunct ones.
Depending on their design and purpose, satellites typically function for 10 to 15 years but can persist in orbit for much longer.
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Unlike previous incidents that were linked to residual battery activity, Australian researchers believe the Relay-2 signal was likely triggered by a sudden electrostatic charge or a small meteoroid strike, both of which can cause unexpected discharges of energy.
Researchers say the frequency burst could pave the way for detecting other sudden electrical discharges, with monitoring systems that are already readily available on article source: Astronomers detect pulse from satellite that has been dead for decades
