From: Doug Jones (random@qnet.com)
Date: Sat Jul 24 1999 - 11:24:33 MDT
Mariner 10 tilted its solar panels to null our sunlight torque and
reduce propellant consumption, ca 1973.
As for spacecraft lasting more than decades, radiation exposure in
space degrades solar cells by inducing crystal dislocations. The
dopants diffuse to the flaws, and the efficiency drops several
percent per year. I don't think there is a floor to this process,
but if you can periodically anneal the cells by heating to around
250 C, the radiation damage is greatly reduced.
Trouble is, this would require some moving parts to scan a
magnifying glass over the panels to do the annealing. As far as I
knoe, it's never been done.
It's difficult to do this for the control electronics, though they
don't degrade as quickly as the solar arrays.
Technotranscendence wrote:
>
<raf@tiki-lounge.com>
> >Satellites with solar sails and gyrodynes could have very very long
> >lifespans. Things should be built to last thousands of years.
>
> If my memory's correct, NASA already did have at least one
> satellite with panels on it that used light pressure to maneuver.
> This was in Earth orbit.
> Anybody else recall this?
-- Doug Jones, Freelance Rocket Plumber
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