Throughout the month of November, AMSAT will celebrate the 50th anniversary of amateur satellite AMSAT OSCAR 7 (AO-7), a SmallSat launched on November 15, 1974.
AO-7 is still working and has been nicknamed the “sleeping beauty” of satellites because it came back to life after years of “sleeping.”
Designed by radio amateurs, the final assembly occurred in a basement laboratory not far from the Goddard Space Flight Center in Maryland. AO-7 lived a very healthy lifetime of 6.5 years but in late 1980, AO-7’s NiCad battery began to show serious signs of increased series resistance. This was a sure sign to AMSAT command stations that the end was in sight for AO-7.
The cells had been originally matched for capacity by NASA and they all failed within a matter of weeks of one another. AO-7 stayed asleep for 21 years, but then one day in June 2002, the satellite woke up again. This was only possible if something caused an open circuit in the battery. On June 21, 2002, a very active user of AO-7, Pat Gowain, G3IOR, from the UK, made a telephone call to Perry Klein, W3PK, the first AMSAT president and designer of the VHF/HF transponder.
Gowain was wondering if a new low-Earth-orbit (LEO) spacecraft had been launched. He was hearing Morse Code telemetry again on AO-7’s old beacon frequency. He played Perry a tape recording and it turned out to be AO-7 telemetry!
AMSAT will honor this historic achievement with a series of short articles highlighting the life of AO-7.
You can visit a special page on the AMSAT website where you will find a collection of AO-7 articles and links at: https://www.amsat.org/amsat-ao-7-a-fifty-year-anniversary/.