Hubble Servicing Flight cancelled...

Or so it seems, anyway.

http://www.spaceflightnow.com/news/n0401/16hubblesm4/

"NASA Administrator Sean O'Keefe told engineers and scientists today
that he has decided to cancel a planned shuttle mission in 2006 to
service and upgrade the Hubble Space Telescope, one of the most
scientifically productive spacecraft ever launched."

(The possible retrieval mission is cancelled, too...)

--
-Andrew Gray

Andrew Gray wrote in
:

Or so it seems, anyway.

http://www.spaceflightnow.com/news/n0401/16hubblesm4/

"NASA Administrator Sean O'Keefe told engineers and scientists today
that he has decided to cancel a planned shuttle mission in 2006 to
service and upgrade the Hubble Space Telescope, one of the most
scientifically productive spacecraft ever launched."

(The possible retrieval mission is cancelled, too...)


Considering that, by law, Nasa is required to provide for the safe disposal
of Hubble, what alternatives are available? The telescope in its present
form has no facility for controlling its re-entry. The plan had been to
retrieve it using the shuttle, or possibly to fit a propulsive module that
would allow controlled re-entry. Without the shuttle neither of these
options are available, i think.

"Marvin" wrote in message
...
Andrew Gray wrote in
:

Or so it seems, anyway.

http://www.spaceflightnow.com/news/n0401/16hubblesm4/

"NASA Administrator Sean O'Keefe told engineers and scientists today
that he has decided to cancel a planned shuttle mission in 2006 to
service and upgrade the Hubble Space Telescope, one of the most
scientifically productive spacecraft ever launched."

(The possible retrieval mission is cancelled, too...)


Considering that, by law, Nasa is required to provide for the safe
disposal
of Hubble, what alternatives are available? The telescope in its present
form has no facility for controlling its re-entry. The plan had been to
retrieve it using the shuttle, or possibly to fit a propulsive module that
would allow controlled re-entry. Without the shuttle neither of these
options are available, i think.


My specialty is fixing people, not satellites, but I still have to ask:

Why not have a rocket-launched repair robot for these situations? It would
undoubtedly be more efficient than a human shuttle crew and would be able to
stay in orbit indefinitely for use whenever a problem turned up. Even
better, you could make one reusable, encasing it in a reentry shell and
returning it to Earth whenever it ran out of fuel or needed to be launched
with spare parts for saay, Hubble.

Doc

In article ,
Marvin wrote:

Considering that, by law,

What law is this? If US law doesn't apply to Guatanamo Bay ... how
could it apply to Earth orbit?

Nasa is required to provide for the safe disposal
of Hubble, what alternatives are available? The telescope in its present
form has no facility for controlling its re-entry. The plan had been to
retrieve it using the shuttle, or possibly to fit a propulsive module that
would allow controlled re-entry. Without the shuttle neither of these
options are available, i think.

According to CNN:
http://www.cnn.com/2004/TECH/space/0....ap/index.html

The Hubble will eventually fall out of orbit and crash to Earth, probably in 2011 or 2012. To make that event safe, Grunsfeld said, NASA will design and build a small robot craft that will be launched and guided to the Hubble.

The robot craft would "grab the Hubble and bring it into the atmosphere in a controlled manner," he said, guiding the school-bus-sized craft to harmlessly splash into a remote part of an ocean

NASA was supposed to have the Shuttle ready to rescue Skylab. Shuttle was
delayed and Skylab killed thousands of australian bushflies and possibly a few snakes.

So, you cancel the Shuttle mission to bring down Hubble, and it isn't very
hard to predict that whatever plans NASA had to rescue Hubble for safe
re-entry will be late and Hubble will again fall somewhere in Australia.

If Hubble is left to its own from now on, how long before its orbit becomes
decayed enough that the telescope will not provide much value to scientists ?
Would this point in time occur before the Shuttle retirement in 2010 ?

Once Hubble's orbit starts to decay sufficiently, does it present a collision
risk with satellites ? or are satellites in orbits below Hubble all able to
use thrusters to avoid collision ?

Frankly, I really do not see why NASA would cancel the plan to rescue Hubble.
It is just as important as completing the station.

In article , Monsieur John Doe
wrote:
NASA was supposed to have the Shuttle ready to rescue Skylab. Shuttle was
delayed and Skylab killed thousands of australian bushflies and possibly
a few snakes.

....and gave a few people some prized souvenirs to display in the trophy
case at home. Lucky people.

So, you cancel the Shuttle mission to bring down Hubble, and it isn't
very hard to predict that whatever plans NASA had to rescue Hubble for
safe re-entry will be late and Hubble will again fall somewhere in
Australia.

Well, not unless Hubble is intentionally deorbited while it still has
sufficient maneuvering propellant for that. They did that with Mir which
worked out ok in the end, but had waited just a little too long to deorbit
while clinging to national pride and a very faint hope of last minute
restored funding for continued use of Mir... to the point where Ground
Control couldn't really make more precise estimations of debris zone due to
having lost some control over maneuvering from waiting too long.

If Hubble is left to its own from now on, how long before its orbit
becomes decayed enough that the telescope will not provide much value to
scientists ? Would this point in time occur before the Shuttle
retirement in 2010 ?

I don't recall details right now, but there was at least one article
presented by interested Hubble-related researchers that floated several
proposals for a Hubble repair / reboost / enhancement mission or two...
they said that unless something happens, they can expect Hubble's orbit to
be reasonably stable (if decaying) until at least about 2011-2012 or so.

Current plans, unless changed, is to deorbit it in 2010... unknown if the
recent proposals will affect the timeline although it seems likely it's a
done deal for deorbiting rather than any future repair/enhancement
missions.

However, I don't know if that takes into effect the upcoming Solar Max
which should be peaking around then... resulting in expansion of atmosphere
(and increased drag, coming down sooner... which is what happened with
Skylab when STS-1 ran late.)

Probably did take that in consideration for HST lifetime without repair or
reboosting, but I just don't personally know that for sure.

Once Hubble's orbit starts to decay sufficiently, does it present a
collision risk with satellites ? or are satellites in orbits below Hubble
all able to use thrusters to avoid collision ?

Satellites generally use maneuvering fuel *extremely* conservatively --
they don't have a comfortable margin for anything other than stretching out
a service life (and hoping nothing requires larger than planned fuel
usage).

It's often so tight that people are more willing to send one on a free
return trajectory around the moon sometimes to fix satellite with Earth
orbit issues rather than waste what precious fuel they have onboard, even
at expense of waiting a while for it to return. (At least one satellite or
maybe two has already done that, for that reason.)

Most likely Hubble would just have to be aimed with some planning -- likely
with tracking data by NORAD -- to hopefully miss significant orbiting
bodies during its final descent to the ground. From what I understand, the
NORAD database of orbiting celestial objects is pretty comprehensive and
well charted and tracked.

If they deorbit while it still has propellant and maneuvering control and
capabilities, they can probably better predict the impact footprint and
keep it as narrow as possible. If they wait too long... well, then you
could have an *huge* potential impact zone like we did with Mir.

Frankly, I really do not see why NASA would cancel the plan to rescue
Hubble. It is just as important as completing the station.

Unfortunately, the bureaucrats in charge of the purse strings don't seem to
share the same passion for science. The ones leading NASA generally
understands; the ones that defines NASA's budget are by definition, career
politicians, and 'for the good of science' doesn't always win when deciding
which projects/proposals/agencies to fund and what stuff to cut. By that, I
mean the White House and Congress has the final say in how NASA is funded;
it is up to NASA's administrator and his/her deputies to stretch every
single allocated dollar. Very difficult situation when there is some
reluctance in Congress to fund the proposed White House plan / vision for
the future of the manned space program.

-Dan

"John Doe" wrote in message
...
If Hubble is left to its own from now on, how long before its orbit
becomes
decayed enough that the telescope will not provide much value to
scientists ?
Would this point in time occur before the Shuttle retirement in 2010 ?


Hubble's scientific usefulness is limited by the lifetime of its onboard
gyroscopes, which fail at the rate of about 1 per year. It has 6
gyroscopes. Two have failed already. If two more fail the Hubble cannot do
science.

Jason

"Jason Rhodes" wrote in message
m...

"John Doe" wrote in message
...
If Hubble is left to its own from now on, how long before its orbit
becomes
decayed enough that the telescope will not provide much value to
scientists ?
Would this point in time occur before the Shuttle retirement in 2010 ?


Hubble's scientific usefulness is limited by the lifetime of its onboard
gyroscopes, which fail at the rate of about 1 per year. It has 6
gyroscopes. Two have failed already. If two more fail the Hubble cannot
do
science.

The important thing here is the Hubble decision has nothing to
do with Shuttle retirement... there would be plenty of money
to do a servicing mission before 2010. The issue is that with
post-Columbia on-orbit inspection requirements, NASA is
reluctant to make any non-ISS missions.

Bruce

Marvin wrote in message
Considering that, by law, Nasa is required to provide for the safe disposal
of Hubble, what alternatives are available? The telescope in its present
form has no facility for controlling its re-entry. The plan had been to
retrieve it using the shuttle, or possibly to fit a propulsive module that
would allow controlled re-entry. Without the shuttle neither of these
options are available, i think.


Look at the positive side. Maybe it will land on the morons making
these decisions.

Hubble is a national treasure which really makes the shuttle program
(and its cost in lives) worth it. I have no doubt that a crew could
be found to make the Hubble upgrades. Go get Story!! If they are so
afraid of having a damaged shuttle in orbit on this mission. Put a
second one on the pad and let Igor support the now defunct ISS for a
few months.

The truth is they saw no contracts for Haliburton so cancelled the
program. Well done Shrub.

JWW45

"Dan Foster" wrote in message
...
In article , Monsieur John Doe
wrote:
NASA was supposed to have the Shuttle ready to rescue Skylab. Shuttle
was
delayed and Skylab killed thousands of australian bushflies and possibly
a few snakes.

...and gave a few people some prized souvenirs to display in the trophy
case at home. Lucky people.

So, you cancel the Shuttle mission to bring down Hubble, and it isn't
very hard to predict that whatever plans NASA had to rescue Hubble for
safe re-entry will be late and Hubble will again fall somewhere in
Australia.

Well, not unless Hubble is intentionally deorbited while it still has
sufficient maneuvering propellant for that.

Hubble does not have a propulsion system.

Ted Molczan