NASA spent $79 Million on LCROSS mission!, page 2

Originally posted by Eurisko2012
reply to post by ngchunter

You seem to have a lot of information about satellites.
6,000 kg?

Yes, optical satellite tracking is a hobby of mine.

Why does it have to be so heavy?

For all the reasons I outlined earlier; big transmitters and receivers require bigger power sources, bigger processors, which requires bigger energy storage, which requires bigger thermal control, which also all requires a bigger chassis, etc, etc, etc...

Don't we have the technology to make things smaller and lighter?
Lightweight polyalloys?
Miniaturization?

Smaller microchips are more susceptible to cosmic rays and other random hits of radiation that can damage electronics. The world's fastest processors are probably far more susceptible to radiation than a living organism.

The whole thing also needs to be rugged to be absolutely sure it can withstand the rigors of launching on a rocket, and it needs to be carefully designed to attain a tolerable temperature in space.

Have you seen a HD Cam recently?

Yes, and again, modern electronics are not space hardened or worthy. But the camera is only the beginning of your issue, I don't understand why you keep bringing it up? Are you trying to oversimplify it intentionally? You can't just focus on the camera part of the issue, the camera's worthless if it can't withstand launch or you can't get the video down in realtime!

I think we can bring the costs and weight down if we think about it.
Instead of a dedicated Comm Satellite, how about a small
space station 22,300 miles away that is manned by NASA
personnel?

Bad idea. The van allen belts may not be an issue if you're just passing through, but if you stay there day after day you're going to be in serious trouble. I also don't understand how this would make anything easier with regards to bandwidth limitations of a lunar probe?

We are going to retire the Space Shuttles soon.
Here is an idea. Think with me.
We launch Discovery. In the payload area we put small booster
rockets.

I believe it was after Challenger exploded that they decided to no longer allow any significant amount of fuel to go in a shuttle's payload bay. Things like boosters are strictly verboten.

Rendezvous with the ISS.
Attach/install small boosters rockets. Head out to the
small space station 22,000 miles away and dock.
Leave it there and as an emergency escape vehicle for
the NASA personnel.

I have some doubts about the ability of the orbiter to safely re-enter from that altitude; its heat shield is not as good as Apollo's with regard to temperature tolerance and energy rejection because it's only designed to handle low earth orbit re-entries, not mid-earth orbit. The shuttle is also much weaker structurally than a capsule. Whereas Apollo's capsules could easily survive very high G re-entries, the shuttle is limited to 2.5g's, no more. It definitely could not survive a trans-lunar re-entry at 11km/sec, from 22,000 miles maybe it could (I'd have to sim it), but you're cutting it close to the edge of survivability.