A short but powerful radio signal has left astronomers stunned — not because of its strength, but because of its source. In June 2024, researchers operating the Australian Square Kilometre Array Pathfinder (ASKAP) detected a burst of radio waves lasting just 30 nanoseconds, and what they found was completely unexpected. The origin of this pulse was not some deep-space phenomenon like a Fast Radio Burst (FRB) from a distant galaxy. Instead, its coordinates pointed back to Earth’s orbit — more precisely, to a long-retired piece of NASA hardware launched during the Cold War.
The source has been identified as Relay 2, a NASA experimental communications satellite launched in 1964 and believed to have gone silent permanently by 1967. The satellite, once a technological pioneer in broadcasting television signals across continents, has remained inactive and unresponsive for nearly six decades. Now, it appears to have sent out one final spark — a literal burst of radio energy — that challenges assumptions about the behavior of derelict satellites. The event is described in detail in a peer-reviewed paper published on arXiv, and it has triggered a wave of speculation and analysis among astronomers and aerospace engineers alike.
A Radio Signal Just 30 Nanoseconds Long, but From Orbit—Not Deep Space
On June 13, 2024, astronomers using the Australian Square Kilometre Array Pathfinder (ASKAP) recorded a sharp radio pulse that initially resembled a Fast Radio Burst (FRB). These events are typically sourced from billions of light-years away. But this time, the signal’s characteristics and trajectory pointed not to the cosmos—but to low Earth orbit.
The signal lasted less than 30 nanoseconds, far shorter than most known artificial or natural radio emissions. Triangulation efforts revealed its source was near the orbital track of NASA’s Relay 2 satellite, launched in 1964 and officially decommissioned in 1967. The satellite was designed as an early experimental communications platform, transmitting television signals and data between continents. Yet for over half a century, no emissions had been detected—until now.
Relay 2: A Zombie Satellite or Just Electrostatic Aftershocks?
The abrupt burst has sparked a debate: did Relay 2 somehow awaken, or was this just the echo of space physics at play? Lead author Clancy James, of Curtin University, suggests that the signal may not be intentional. One hypothesis involves electrostatic discharge (ESD)—a buildup of electrical charge on the satellite’s surface that spontaneously discharged. This phenomenon, while previously detected in satellites and even at Arecibo Observatory, had never been recorded on such a short timescale.
An alternative theory points to micrometeoroid impacts. A high-speed grain colliding with the satellite might have generated a plasma cloud, creating a momentary electromagnetic pulse. Events like this are invisible to the naked eye but may influence radio frequency interference and satellite diagnostics.
Wake-Up Calls in Space: The Case of Zombie Satellites
Although this instance may not reflect a true reactivation of the satellite, the story evokes memories of so-called zombie satellites—spacecraft presumed dead that later resume activity. A prominent case is Galaxy 15, which went silent in 2010 and unexpectedly rebooted itself months later. Similarly, AMSAT-OSCAR 7, launched in 1974 and thought lost after a battery failure in 1981, began transmitting again in 2002—21 years later.
Such events challenge assumptions about satellite dormancy. Long-dead spacecraft are still subject to thermal cycling, radiation, and collisions, making them potential sources of radio contamination, posing threats to radio astronomy and communication systems.