Thanks for the information on all of those things.  Hopefully someday we can see some more FM satellites with this sort of lifespan!

73 John AF5CC

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---- On Mon, 22 Jul 2024 12:06:57 -0500 Paul Stoetzer via AMSAT-BB amsat-bb@amsat.org wrote ---

1. It's a microsat size satellite, so significantly larger than current cubesat form factors.2. It's transmit power is just 250 mW and it transmits only while it receives a signal with a 67 Hz PL tone - there's no constant carrier or any telemetry transmissions. I'm not aware of any other payloads or signals coming from the satellite. Potentially there's not even any onboard computer drawing power.

3. Given its size, it has fairly large solar cells and likely has fairly large battery cells and given its transmit setup, the depth of discharge is likely quite low. NiCd batteries can last a real long time when the depth of discharge is kept quite low.

73,

Paul, N8HM

On Mon, Jul 22, 2024 at 12:05 PM JOHN GEIGER via AMSAT-BB mailto:amsat-bb@amsat.org wrote:

SO-50 will be 22 years old in December and seems to be still be going strong, in sunlight and in eclipse.  No other satellite launched since then has lived near that long.  So what is SO-50s key to long life?  Is it how the satellite was built?  Something in its operation, like lower power on transmit?  Its orbital setup?

Any ideas why it has lived so much longer than the recent crop of AMSATS?

73 John AF5CC

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