ISS till 2028?

"Pat Flannery" wrote in message
one...
On 3/13/2010 11:55 AM, Brian Thorn wrote:

Post-2020, replace the solar panels with solar dynamics for more
power/less drag/reduced need for batteries?


They looked into the reflector/heat engine ones at the beginning of the
ISS program (in fact clean back when they were working on Space Station
Freedom), but decided the solar cell arrays were a better choice.

They were a "better choice" only because they were cheaper to develop. In
the long run, solar arrays require batteries that need periodic replacement
and the solar cells themselves degrade over time.

Solar dynamic power planned on using thermal storage of power, so no
replacement of batteries would be required. Presumably, this would have
been a big "win" in terms of lower maintenance.

One problem I can see for the reflector type is degradation of the
reflecting surface due to atomic oxygen, UV exposure, and radiation.
The mirrored thermal blankets on Hubble deteriorated badly between the
launch and the first maintenance visit, and a lot of the test materials on
the exterior of the the Long Duration Exposure Facility had completely
vanished by the time it was finally recovered after the grounding due to
the loss of Challenger.

I work with a guy who worked on the optical concentrator design for Freedom.
The reflector degrading over time due to atomic oxygen, ultraviolet
radiation, and micrometeorite impacts was a definite concern.

Jeff
--
"Take heart amid the deepening gloom
that your dog is finally getting enough cheese" - Deteriorata - National
Lampoon