Posted by Scott Johnson on January 17, 2000 at 20:16:13:
In Reply to: Hubble Servicing posted by Puzzled on January 16, 2000 at 15:39:53:
> I'm a bit puzzled about the entire Hubble servicing philosophy. Since
> the on-orbit repair and replacements seem to be rather difficult (with
> huge amounts of pre-flight training), why don't we simply de-orbit the
> Hubble in the cargo bay and reboost it on the next mission.
Of course you still would need pre-flight training for this, so that
cost would only be slightly diminished if at all. Remember you
would have to train on stowing the HST, which I could imagine would
be very difficult and would require lots of training.
> I'm sure
> some would say that that takes two flights where one would do, but it
> seems that we could schedule the pickup missions with on board science
> and/or satellites that could be released near Hubbles orbit.
Remember that every item you put on the Shuttle makes it all the more
heavier. This will limit how high the Shuttle can go (and you
want it to go very high). Also, any additional satellites would
lengthen the mission (as they would need to devote time to releasing
them). There are limits to the fuel (both Shuttle and human) aboard
also. If the method you suggest was followed, the Shuttle would be
devoted only to the retrieving of the HST.
> I do realize that many birds have very specific orbital requirements
> so there would be delicacy in scheduling. Overall, this would allow full
> refurbishment of systems in an environment much easier to do repair
> and replacement of components-on the earth.
> I'm sure NASA has kept all
> the packaging components necessary for the reorbit of the Hubble. I'm
> also sure to retrieve the Hubble in the cargo bay would probably
> require a space walk, but again, this seems much easier than the
> complicated on-orbit repair missions. Can someone enlighten me?
>
>
It's complicated either way. The "bringing down HST to Earth" method
would loss many months of scientific observations (maybe even years
if the Shuttles have lengthy delays) and would probably cost more
(possibly substantially more) than the current on-orbit servicing missions.
Scott