The Hubble Space Telescope...

Jorge R. Frank wrote:
A Hubble Hubble wrote in
:


Jorge R. Frank wrote:

(Explorer8939) wrote in
.com:


Johnson Space Center wants to use 2 Shuttles for a
servicing mission, one for the prime mission, one as a backup in case
the first Shuttle has problems inflight and the crew needs to be
rescued.

Incorrect. JSC is *studying* the option of a rescue shuttle in the
even that GSFC *wants* an HST servicing mission before the shuttle
program has standalone repair capability. JSC does not *want* to use
a rescue shuttle; it would *prefer* to delay the next HST servicing
mission until standalone repair capability is available.

It is my understanding that the HST mission will not fly until there
is a tile repair procedure in place that does not require the orbiter
to be attached to the station. RCC repair is another matter. There
may never be an RCC repair procedure for holes greater than a certain
size, so if that were to happen again,


Keep in mind that once the ET foam-shedding problem is mitigated, this is a
*very* low-probability event.

I wonder at what point NASA, the Return to Flight Task Group, Congress,
and the CAIB (if they do get back together) will feel comfortable enough
with the ET fixes that NASA won't have to fly the starboard boom and a
tile repair kit and whatever RCC repair kit that is decided upon.


station would be the safe haven
for the crew during an ISS mission. Since there is no "safe heaven"
in the HST orbit plane, the NASA powers that be have decided to have
that stand-by shuttle on the pad for a crew rescue.


Almost true, except for your use of "have decided". That is incorrect. The
correct words would be "are studying".

Yes, I used too strong a term. But those who are "studying" the vehicle
on the pad scenario and the fact that the next HST mission is currently
scheduled for when all three orbiters are available (so as to reduce the
impact to station by having a standby orbiter on the pad) leads me to
believe that it's only a matter of time before it becomes official.

On 2003-11-28, MasterShrink wrote:

Besides, that's all it would be to see the HST retrieved...nice. Before
Columbia was lost I expected to walk into the Smithsonian 20 years from now and
see the Hubble resting beside one of the orbiters, but that isn't really
important now and history will note that.

Agreed. And it would probably have been Columbia. But as you say, that
really isn't important now.


Iain

Louis Scheffer wrote in
:


This is not true, except for the very first batch of instruments, all
long since replaced. There are no additional lenses in any of the
insruments designed since the flaw was uncovered.
In all the new instrucments, since they need one or more
mirrors to direct the light within their own optics, they just need to
make one or more of these mirrors not quite flat. This restores
diffraction limited optical performance without adding any new
elements.



But since not flat is harder to make than flat. Is it still as good
as it could have been if they did the job correctly the first time.
You may think so. But I don't. Having worked at NASA and for Uncle some
26 years the one thing I learned is the PR is usually more optimisic
than what reality is.


David A. Scott
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"Jorge R. Frank" wrote in message ...


Johnson Space Center wants to use 2 Shuttles for a
servicing mission, one for the prime mission, one as a backup in case
the first Shuttle has problems inflight and the crew needs to be
rescued.

Incorrect. JSC is *studying* the option of a rescue shuttle in the
even that GSFC *wants* an HST servicing mission before the shuttle
program has standalone repair capability. JSC does not *want* to use
a rescue shuttle; it would *prefer* to delay the next HST servicing
mission until standalone repair capability is available.


Jorge, perhaps the words "are planning" are more accurate to describe
NASA's current activities in regards to the 2 Shuttle Hubble Servicing
Mission. Since, AFAIK, JSC isn't planning any other scenario at this
time (although GSFC is), my original assessment remains correct.
However, I agree that stating that JSC "wants" to perform the 2
Shuttle scenario is incorrect, if given a chance JSC would 'rather'
not fly the Hubble mission at all (in the sense that buildings want to
do anything).

A Hubble Hubble wrote in
:

Jorge R. Frank wrote:

Keep in mind that once the ET foam-shedding problem is mitigated,
this is a *very* low-probability event.

I wonder at what point NASA, the Return to Flight Task Group,
Congress, and the CAIB (if they do get back together) will feel
comfortable enough with the ET fixes that NASA won't have to fly the
starboard boom and a tile repair kit and whatever RCC repair kit that
is decided upon.

Those are probably with us for the life of the program. I *could* see
people getting comfortable with leaving the boom/repair kits at ISS, saving
the performance hit from bringing them up every time, while sucking up the
risk of not docking (or a mishap post-undocking).

station would be the safe haven
for the crew during an ISS mission. Since there is no "safe heaven"
in the HST orbit plane, the NASA powers that be have decided to have
that stand-by shuttle on the pad for a crew rescue.


Almost true, except for your use of "have decided". That is
incorrect. The correct words would be "are studying".

Yes, I used too strong a term. But those who are "studying" the
vehicle on the pad scenario and the fact that the next HST mission is
currently scheduled for when all three orbiters are available (so as
to reduce the impact to station by having a standby orbiter on the
pad) leads me to believe that it's only a matter of time before it
becomes official.

I wouldn't take the FAWG manifest too seriously (if that's the one you're
referring to); the HST flight has moved around quite a bit on that manifest
the last few months. Anything after STS-116 is written in sand.

Tying the HST flight to the periods when three orbiters will be available
takes the burden off ISS, but it's a schedule trap for the shuttle program:
these periods are short, and OMMs are tied to both number-of-flight and
calendar month. So if an HST flight in that short period starts to slip,
there will be tremendous schedule pressure to try to keep it in that
period, to keep the rescue shuttle available. That would be a mistake, IMO.
Better to let the flight slip, forget the rescue shuttle, and just suck up
the miniscule risk that something bad might happen on that flight. NASA
took that risk on the previous HST flights, and nothing *real* has changed
since then - only the *perception* of risk.


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(Explorer8939) wrote in
om:

"Jorge R. Frank" wrote in message
...


Johnson Space Center wants to use 2 Shuttles for a
servicing mission, one for the prime mission, one as a backup in
case the first Shuttle has problems inflight and the crew needs to
be rescued.

Incorrect. JSC is *studying* the option of a rescue shuttle in the
even that GSFC *wants* an HST servicing mission before the shuttle
program has standalone repair capability. JSC does not *want* to
use a rescue shuttle; it would *prefer* to delay the next HST
servicing mission until standalone repair capability is available.


Jorge, perhaps the words "are planning" are more accurate to describe
NASA's current activities in regards to the 2 Shuttle Hubble Servicing
Mission. Since, AFAIK, JSC isn't planning any other scenario at this
time (although GSFC is), my original assessment remains correct.

The current manifest (which "A Hubble Hubble" referred to) shows HST SM-04
on STS-124, with no rescue shuttle on the pad.

However, I agree that stating that JSC "wants" to perform the 2
Shuttle scenario is incorrect, if given a chance JSC would 'rather'
not fly the Hubble mission at all (in the sense that buildings want to
do anything).

I disagree.

--
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Craig Fink wrote:

Hi Brian,

I agree with you 100%, there is still plenty to be learned from the Hubble
if it were to be brought safely back to earth. Maybe not from an
astronomers point of view, but an engineering point of view. Launched in
1990, with a planned end of mission in 2010, that gives it 20 years in the
low earth orbit environment.

Another low earth orbit environment study, was LDEF, had it's stay in orbit
extended by the Challenger disaster. But, Hubble has spent much more time
in space. Plus, from an engineering standpoint, I would think it would be a
great study on orbital debris. It could even be used as a control in future
leo orbital debris studies. A great turn of the millennium orbital debris
data point. Especially if it is allow to continue to 2010, 10 before and 10
years after the year 2000.

The tube or sun-shield essentially blocks half the sky from orbital debris
from impacting the inside of the tube. It's entire attitude history is well
known. I would think that it would be very interesting to see what the
impact distribution inside the tube looks like, as well as impacts to the
mirror and exterior.

It would be hard to come up with a better control data point for future
orbital debris studies.

It just doesn't seem right to have a dummy model of anything in a museum.

Then why not retrieve one of the lunar modules from the Moon and bring
it back for study and then placement in the Smithsonian? Would that be
less important than Hubble?

In article ,
David A. Scott wrote:
Interesting its not worth the RISK OF LIFE to bring it back
but it is worth the RISK OF LIFE to attach a rocket to it to
up burn it up in the atmosphere.

No, the rocket attachment could be done as part of the last servicing
mission (there is at least one more planned), so it would not involve any
added risk.

I wonder if anybody has done
some sort of environmental study about the tradeoffs since the
mission itself and the rocket attached will add more pollution
to the air.

Completely insignificant compared to all the other stuff that goes into
the atmosphere.
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pointing, 10 Sept; first science, early Oct; all well. |

"Scott M. Kozel" wrote in message
...

It just doesn't seem right to have a dummy model of anything in a
museum.

Then why not retrieve one of the lunar modules from the Moon and bring
it back for study and then placement in the Smithsonian? Would that be
less important than Hubble?

Reason 1: Salvage 1 has already done that.

Reason 2: You realize only the descent stage is still there and that's
rather prosaic compared to the ascent stage.

"Greg D. Moore \(Strider\)" wrote:

"Scott M. Kozel" wrote:

It just doesn't seem right to have a dummy model of anything in a museum.

Then why not retrieve one of the lunar modules from the Moon and bring
it back for study and then placement in the Smithsonian? Would that be
less important than Hubble?

Reason 1: Salvage 1 has already done that.

Done what?

Reason 2: You realize only the descent stage is still there and that's
rather prosaic compared to the ascent stage.

My language above was meant to include both. The descent stage would be
retrieved from the surface of the Moon, and the associated ascent stage
would be retrieved from lunar orbit.

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