For an entire year, a team of scientists in Western Australia puzzled over a single radio wave that seemed extremely unusual. It was exceptionally fast (just 30 nanoseconds), far stronger than anything they had ever seen before, and even briefly managed to outshine all the other celestial signals.
When the ASKAP telescope system (a network of 36 radio antennas) picked up the signal in June 2024, astronomers were thrilled. “We thought maybe we had discovered a new pulsar (a spinning neutron star that emits electromagnetic radiation) or a phenomenon we didn’t know about,” said Dr. Clancy James of Curtin University to New Scientist. The initial suspicion: A fast radio burst (FRB)—a rare phenomenon that usually comes from distant galaxies and is emitted by extremely dense neutron stars.
But something didn’t add up. The problem: The signal was too strong and many times “brighter” than any other cosmic source. In fact, the more precise the measurements became, the clearer it was that it originated within our own galaxy. Then they narrowed it down even more, and that’s when the real surprise came: the signal’s source was NASA’s dead satellite, Relay 2, which was launched back in 1964.
Relay 2 was part of an experimental NASA program for intercontinental communication and only functioned for a short time. Its predecessor, Relay 1, was the first satellite in history to transmit television from the United States to Europe and Japan, with its eerie debut broadcast being the assassination of President John F. Kennedy. Relay 2 was launched in 1964, operated for about a year, and continued emitting weak signals until 1967, then went completely silent.
So when on June 13, 2024, researchers picked up a brief burst of radio waves from its orbital area, they were stunned. For a moment, the signal appeared to come from a pulsar (a spinning neutron star that emits electromagnetic radiation) or some other astrophysical source, but it was only just revealed to be the “final cough” of an ancient piece of space junk.
Why would a satellite that died decades ago suddenly emit such a strong radio signal?
The first theory is that Relay 2 simply built up static electricity during decades of drifting through plasma in space, until one powerful, brief, and unintended discharge was released. A similar phenomenon was observed from the ground by the Arecibo Observatory, although in longer signals. Researchers explain that modern satellites are built with materials that prevent discharges, but in the 1960s this wasn’t taken into account.
A second possibility is that NASA’s old satellite was hit by a micrometeoroid, a tiny piece of space rock ranging in size from a micron to a few millimeters. Despite its tiny size, a micrometeoroid travels at tremendous speeds—tens of kilometers per second—so even a slight impact could be enough to create a plasma cloud and emit short but powerful radio waves. This might be exactly what happened to the satellite: The plasma cloud released by the hit transmitted the unusual signal toward Earth.
However, the research team emphasizes that such impacts are relatively rare. They estimate that the more likely explanation is indeed a static electricity discharge—a phenomenon where old satellites, built before the risks were understood, absorb electrical charges over the years until a strong spark is suddenly released. Even so, they assure: This is not a comeback of lost technology, but rather a final signal from a decades-old piece of space debris.
The scientists clarify that this is not a case of a “zombie satellite,” a term used to describe satellites that suddenly resume transmission after years of silence. Such examples exist: In 2002 the amateur satellite OSCAR-7 came back to life after 21 years of silence, and in 2010 the communication satellite Galaxy 15 rebooted itself after being abandoned in orbit. But in the case of Relay 2, this was not an awakening but a breakdown—brief, violent, and one-time only.
Meanwhile, the researchers note that although this is a rare event, it may offer valuable insights. Such electrical discharges, which they refer to as ESD (electrostatic discharge), can disrupt equipment, destroy sensitive components, and interfere with the reception of signals from space. Therefore, monitoring such signals may, in the future, serve as a diagnostic tool for detecting dangers in satellites—or at least help differentiate between signals from the universe and signals from orbiting space junk.
Is this a warning sign? Not necessarily. But the next time you hear about a “mysterious signal from space,” keep in mind—it might just be an old electronic remnant from the past, still whispering something, just before it goes silent again forever.