In article om,
says...

Question about debris:

If a stage 3 separates before stage 2 has finished its burn, would it
simply jump ahead of stage2 only to be caught by still accelerating
stage 2 and the collision would then cause damaghe and debris ?

Not necessarily. I believe that SpaceX had something very much like
this happen on one Falcon 1 flight and it resulted in the lower stage
recontacting the upper stage.

Would would such a sepoaration not have enough "oumph" to allow stage 3
to separate from 2 because 2's acceleration is greater than the push
that 3 makes to get ahead of 2 ?

Or would depris point to an Apollo 13 style explosion ?

An impact could certainly result in structural failure and rapid loss of
pressure in one of the tanks.

The "spinning" video at:
http://www.space.com/29241-glitch-ru...rol-video.html

Indicates more of an agena type of spin (from the HBO "From Earth to the
Moon" along pitch axis rather than just a simple spin along yaw.

Assuming this rotation continues, won't that mess up re-entry
predictions ? Or would a rotating vehicle present fairly similar drag
coefficient ?

This is all estimation. You estimate the frontal area based upon the
average area presented over time. So yes, the rapid, consistent,
spinning allows for a better estimation of drag than for a vehicle is
slowly tumbling (rotating in what appears to be a random manner).

Are autopilots capable of recovering from such a extreme situation ? If
"below" the horizon, the autopilot may command a raise in pitch to reach
targhetted horizon, but that firing may accelerate the spin (when one
should detect the spin and fire against it no natter what your current
attitude is).

I doubt the Progress "autopilot" is that capable. In a situation like
this, the Russians would rely on remote control. But, with the
spinning, reliable communications necessary to command Progress might be
impossible. If you can't command it, it's not going to stop spinning.

Depends on other details too. In this case, it appears there is no fuel
left. If this means no fuel for the reaction control system then there
is no chance to fix the spin no matter what. Off the top of my head, I
don't know if the reaction control system shares fuel tanks with the
main propulsion system on a Progress.

Also, would solar panels still be able to feed Progress with enough
power in this constant rotation to stay awake, or is the ship already
asleep due to power starvation ?

Depends on the details, but it's got some battery capacity too. I've
not heard of power starvation problems. That could be a problem, but
that's secondary compared with complete loss of fuel and/or the
inability to command the Progress.


We should all keep in mind that Progress and Soyuz are closely related.
They fly on the same launcher and share many common systems (like the
service module, which is likely where this mission failed). Without a
reliable US manned space "taxi", the Russians had better figure this one
out quickly in order to keep the station manned.

Jeff
--
"the perennial claim that hypersonic airbreathing propulsion would
magically make space launch cheaper is nonsense -- LOX is much cheaper
than advanced airbreathing engines, and so are the tanks to put it in
and the extra thrust to carry it." - Henry Spencer