[amsat-bb] Re: AO-07 healthy CW
Tom Clark, K3IO
K3IO at verizon.net
Mon Nov 27 21:07:39 PST 2006
N4HY sent this note:
> There was one series string of Nicads as can easily be discerned from
> this photograph:
> You can notice the series string starts at the upper left and works its
> way right and then down to the lower string and back to the left.
Those are sealed, space-rated NiCd batteries built to NASA's
specification. The package you see is the flight spare for the Radio
Astronomy Explorer (RAE) satellites. They originally cost ~$2000 per
cell. With later satellites, AMSAT found that we could "make our own"
batteries that were better by carefully screening industrial-grade
commercial batteries by following a recipe devised by the late Larry
RAE-A = Explorer 38
launched July 4th, 1968 flew in MEO. This satellite had a a pair of
Vee-beam antennas which provided gravity gradient stabilization. With
each Vee-beam being 750' long, the satellite's 1500' total length made
it the biggest structure put into space. The antenna booms were made of
flat beryllium copper tape that formed itself into a round tube after
RAE-B = Explorer 49 flew June 15th, 1973 into Lunar orbit
also had the same long Vee-beam antenna. The very lumpy lunar gravity
field made for interesting problems with the gravity gradient booms!
FYI -- I note with some pride that I came to Goddard in 1968 as a staff
scientist working on RAE-A and then RAE-B. I migrated from low-frequency
radio astronomy into Pulsar and VLBI work.
FYI#2 -- In addition to the flight spare batteries, Oscar-8's 10M
antennas owed their existence to the RAE project.
73, de Tom K3IO (ex W3IWI)
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