Long-Dead NASA Satellite Emits Powerful Radio Pulse, Baffling Astronomers

What's Happening?

NASA's Relay 2 satellite, launched in 1964 and silent since 1967, emitted a powerful radio pulse that briefly outshone all cosmic sources above Earth. The pulse was detected by the Australian Square Kilometre Array Pathfinder (ASKAP) during a routine search for fast radio burst signals. The pulse's dispersion measure indicated it was local, not interstellar, and matched a single hop through the ionosphere. The source was identified as Relay 2, which carries no active transmitters, suggesting the pulse was triggered externally, possibly by an electrostatic discharge or a micrometeoroid impact.

Why It's Important?

This unexpected radio pulse highlights the potential for derelict satellites to produce significant radio emissions, which could interfere with astronomical observations. Understanding these emissions is crucial for improving the accuracy of transient surveys and preventing misclassification of local signals as cosmic events. The detection also offers insights into electrostatic discharges in space, which can affect active spacecraft and pose risks to astronauts. This event underscores the need for monitoring space debris and developing techniques to evaluate electrostatic discharges, which could enhance spacecraft safety and operational protocols.

What's Next?

Astronomers are developing software triggers to capture more detailed data from similar events. Efforts are underway at other observatories to monitor dead satellites during meteor showers, potentially offering passive monitoring of electrostatic discharges. This could lead to real-time warnings for spacecraft operators, helping prevent cumulative damage. Policy changes may be needed to establish radio-quiet zones, reducing interference with astrophysical data. The Relay 2 incident serves as a reminder of the challenges posed by space debris and the importance of maintaining clear communication channels in orbit.