AMSAT-OSCAR 7: the Ham Satellite That Refused to Die
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Summary
When the AMSAT-OSCAR 7 (AO-7) was launched in 1974 it was expected to have a lifespan of five years, however, in 1981 a battery failure meant the satellite was written off as dead.
Then, in 2002 the satellite made a surprise comeback, with a theory being that one of the cells in the satellite’s NiCd battery pack had shorted open, thus allowing the satellite to run off its solar panels intermittently.
The satellite, which is in a geocentric LEO orbit, has continued to operate for the past 50 years due to its clever use of the Earth’s magnetic field and the impact of photons to maintain its spin, alongside its relatively high altitude.
It features two radio transponders and four beacons, with its descent into bankruptcy attributed to an international treaty affecting the 13cm beacon.
