A Surprising Discovery: Fast Radio Burst from a 60-Year-Old Satellite

In a remarkable turn of events, astronomers have uncovered a fast radio burst that originated much closer to Earth than previously anticipated. This discovery, made on June 13, 2024, using the Australian Square Kilometer Array Pathfinder (ASKAP) radio telescope, has opened new avenues in our understanding of cosmic signals and the potential for monitoring satellites in orbit.

The ASKAP radio telescope, located in the remote Murchison Radio-astronomy Observatory in Western Australia, was employed to search for elusive fast radio bursts (FRBs)—brief yet powerful flashes of radio waves from deep space. These bursts are known to emit energy equivalent to 30 years’ worth of sunlight in mere milliseconds. However, the burst detected on that fateful day did not exhibit the expected dispersion, suggesting it originated from within our galaxy, a significant deviation from the billions of light-years typically associated with other FRBs.

As researchers delved deeper into the data, they encountered a perplexing challenge: the radio burst appeared to vanish from their recordings. After two months of troubleshooting, it became evident that the issue stemmed from the telescope’s configuration. The ASKAP, consisting of 36 antennas, was initially capturing the signal as if it were a distant object, resulting in a blurry image. By adjusting the configuration to reduce the effective size of the “lens,” researchers finally isolated the burst.

However, the excitement of discovering a new astronomical signal quickly turned to disappointment. The blurriness indicated that the signal was likely a case of radio-frequency interference—human-made signals that can contaminate astronomical data. Yet, the burst’s characteristics were intriguing. Lasting only 30 nanoseconds and consisting of a bright pulse followed by two dimmer after-pulses, it was unlike any other known FRB.

Upon investigating the direction of the signal, researchers estimated its source to be approximately 4,500 kilometers away—pointing directly to Relay 2, a defunct telecommunications satellite launched by the United States in 1964. But could this ancient satellite be responsible for the burst?

The idea of “zombie satellites,” which can unexpectedly reawaken, was considered, but Relay 2 lacked the capability to produce such a brief burst during its operational lifetime. Instead, researchers theorized that the burst could have been caused by an electrostatic discharge. As satellites traverse the electrically charged environment of space, they can accumulate charge, leading to sudden discharges that may generate radio waves. However, typical electrostatic discharges last thousands of times longer than the burst observed.

Another hypothesis involved a micrometeoroid strike, similar to an incident experienced by the James Webb Space Telescope in June 2022. A tiny piece of space debris hitting Relay 2 at high speed could theoretically produce a flash of radio waves, but the chances of this occurring were estimated at only 1%.

Despite the uncertainty surrounding the origin of the burst, the research has illuminated new possibilities for monitoring satellites in orbit. The findings suggest that by adjusting the observational parameters, astronomers can detect similar signals, paving the way for advancements in satellite monitoring as the number of objects in space continues to grow.

Ultimately, while the exact cause of this intriguing radio burst remains elusive, it has sparked renewed interest in the potential for discovering new astronomical signals. As researchers continue their explorations, the cosmos may hold many more surprises waiting to be uncovered.