[amsat-bb] New satellies / Shuttle question
G0MRF at aol.com
Sat May 31 01:40:50 PDT 2008
Hi Edward / group.
Most current construction or feasility study is centered on P3E / Eagle /
Intelsat /HEO where launch opportunities are rare and costs are high.
Perhaps we should look at this problem from another viewpoint. Start with
what launch opportunities AMSAT can afford and then retake the technology
initative and investigate what minaturised payloads can we launch for that price?
For example. Imagine a 2 or 3U cubesat type structure, or even one half the
size of AO-51 on last weeks Russian launch to 1500km. With payloads reduced
to transponders and a basic onboard computer and an Electrical Power System,
it would be feasable to put RF comms equipment into a decent orbit on 29MHz
145MHz 435MHz with an RX on 1269.
For bands higher than 13cm doppler is a problem and path loss is quite high.
It may not be possible to provide the necessary DC power for transmitters
in a small structure.
Talking of DC power, the number of cubesats that fail due to power problems
is huge. The answer is to get inventive with deployable solar arrays. With
the engineering excellence AMSAT possesses it should not be impossible to
arrange a structure where the entire outer layer contains extra solar cells that
are deployed after seperation from the launcher. Imagine a 3U cube which in
orbit becomes a 3U box of electronics covered in cells, with an extended outer
3U shell that deploys forming a 6U structure producing nearly double the DC
power. The 6U structure also makes antenna design easier
For a slightly more risky idea.....small satellite propulsion. Again,
perhaps 3U cube, with the last section comprising a small motor. A single burn
unit could provide a really nice elliptical LEO orbit, perhaps 680km to 2000km.
Wouldn't that be interesting. I notice that there is an Austrian university
team who have developed a cubesat sized ion propulsion system asking if
anyone would like to try it. So, while this may initially seem a 'wild idea' it
is based on technology that is very nearly a reality.
In a message dated 30/05/2008 23:22:37 GMT Standard Time, vk3jed at gmail.com
At 12:15 AM 5/31/2008, Edward Cole wrote:
>Once you total the costs it may actually be cheaper to build a new
>satellite and launch it!
>Back the effort for P3E and Eagle/P4.
That too, yes, a new bird would be the easiest approach
indeed. Still, as I said, it was interesting contemplating how such
a recovery might be achieved with today's technology. :)
73 de VK3JED
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