Zombie Satellites: How Abandoned Spacecraft Come Back to Life from Beyond the Grave

Long-dead satellites that were abandoned in orbit are sometimes detected transmitting signals again, sometimes decades after falling silent. This video explains why this happens, using real cases to show how battery chemistry and unexpected engineering quirks can revive spacecraft years or even decades after they were written off.

■ Zombie Satellites That Returned on Their Own
- LES-1: a 1965 MIT Lincoln Laboratory test satellite that fell silent in 1967 and was re-detected by radio amateurs in 2012
- Nickel-cadmium battery chemistry: how cadmium growth creates a short, and how it can later break open and restore power to the spacecraft
- AMSAT-OSCAR 7: a 1974 amateur radio satellite that went silent in 1981 and resumed transmitting telemetry in 2002
- IMAGE: a NASA magnetosphere imaging satellite lost in 2005, briefly contacted again in 2018 after a deep eclipse forced a reset
■ A Satellite Revived Deliberately
- BSat-1: a CubeSat from Technical University of Berlin that stopped returning valid data
- Reconstructing a missing engineering model from salvaged parts to test commands
- Uploading software corrections in 4-byte packets during short passes, and a dormant camera unexpectedly producing images

This is suited to viewers interested in space history, amateur radio, satellite engineering, and how real hardware fails and recovers. Watching it gives you a concrete understanding of why "dead" spacecraft can keep working and what it takes to bring one back. Consider looking up the referenced amateur radio satellite organizations and mission archives to explore the topic further.