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Author Topic: Could there be such a thing as a "dead SAT"?  (Read 1958 times)
WO7R
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Posts: 948




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« on: December 16, 2014, 10:31:41 AM »

I don't know beans about amateur satellites, but I've often wondered if we could have some sort of "dead" satellite and simply bounce signals off of it.

The thinking is rather simple:  If we can do EME on an object that is rather far away and not metallic, couldn't we do the same thing on an object rather closer to hand, and made of some kind of metal mesh?

Imagine, say, a ball-shaped satellite that had "the right diameter" and thickness of mesh to reflect signals in the VHF range.

Such a thing might create some problems in non-ham bands, but to an extent, the ISS kinda sorta is already functioning in an analogous role.  As would any larger satellite, I suppose?

The moon is, after all, very far a way and not a metallic object.  What if we had a metallic object in (say) a Molniya orbit and we reflected highly directional "high enough power" signals off of that?

Nowadays, we'd probably have to have such an object be able to deorbit, but that might be accomplished simply by having its perigee low enough to nick the atmosphere, ensuring its eventual decay on a failsafe basis, never mind whatever kind of telemetry-and-control that would be required to be there for a deorbiting?

Getting the mesh to expand from some small core would be a bit of clever engineering, but as far as telemetry and all the rest, it would be pretty simple.  Maybe a cubesat plus?

Or, are these things so rare and expensive to get up there that it isn't worth the trouble?  Thing is, without active telemetry and band shifting, one could argue that it would count the same as EME for awards, which is one motivation and potential simplification another.  If it worked, after all, all that is necessary is for it to be in orbit and then that's that.  The potential for a fairly long lifetime seems to me a plus.

I suppose this is just too easy an idea to actually be worth it?
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KU6J
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Posts: 22




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« Reply #1 on: December 16, 2014, 12:15:44 PM »

This is technically feasible and has been done before (but not by amateurs):

http://www.nasa.gov/centers/langley/about/project-echo_prt.htm

http://en.wikipedia.org/wiki/Project_Echo

ETA: I don't know whether we amateurs would be able to make effective use of it, however:

http://history.nasa.gov/SP-4217/ch5.htm

Quote
Pierce and Kompfner believed that the required [42] ground equipment for the experiment would be two sixty-foot steerable antennas connected to high-power modulators and amplifiers, low-noise receivers, band compressors, servo-tracking apparatus, and computer facilities.
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« Last Edit: December 16, 2014, 12:23:15 PM by KU6J » Logged

73,

Eric KU6J

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