Hubble Question...

With or without any future service the Hubble will some day go offline.
There have been a lot of ideas floating around as to what to do then.
I was wondering if it could be possible to boost it to a LaGrange Point,
rather than de-orbit it? Is an earth-moon point stable? I know the
earth-sun point can be used as the SOHO satellite is there, but it
would require a lot more fuel to reach. Apparently, recovery of the
Hubble for placement in the Smithsonian is not possible, so I wanted
to put an alternative idea out for discussion.
Bruce

"Bruce Kille" wrote in news:xx9Tb.14283$Vg3.1349
@bignews5.bellsouth.net:

With or without any future service the Hubble will some day go offline.
There have been a lot of ideas floating around as to what to do then.
I was wondering if it could be possible to boost it to a LaGrange Point,
rather than de-orbit it? Is an earth-moon point stable?

In theory, the L4/L5 points are stable, but in the Earth/moon system, all
five points are unstable due to the eccentricity of the moon's orbit and
the influence of the sun.

I know the
earth-sun point can be used as the SOHO satellite is there, but it
would require a lot more fuel to reach.

Not *a lot* more - both require a delta-V near escape velocity, or around 3
km/s.

The problem with putting HST outside low Earth orbit is that its pointing
system relies on geomagnetic torquers to desaturate its reaction wheels.
Move HST out of the Earth's magnetic field, and you've got to find some
other way to do that. Also, HST's comm system relies on TDRS, and accessing
TDRS from well outside GEO is questionable at best.

Apparently, recovery of the
Hubble for placement in the Smithsonian is not possible, so I wanted
to put an alternative idea out for discussion.

Recovery of Hubble remains technically possible, but NASA has ground-ruled
it out for safety reasons.

"Jorge R. Frank" wrote in message
...
"Bruce Kille" wrote in news:xx9Tb.14283$Vg3.1349
@bignews5.bellsouth.net:

With or without any future service the Hubble will some day go offline.
There have been a lot of ideas floating around as to what to do then.
I was wondering if it could be possible to boost it to a LaGrange Point,
rather than de-orbit it? Is an earth-moon point stable?

In theory, the L4/L5 points are stable, but in the Earth/moon system, all
five points are unstable due to the eccentricity of the moon's orbit and
the influence of the sun.

I know the
earth-sun point can be used as the SOHO satellite is there, but it
would require a lot more fuel to reach.

Not *a lot* more - both require a delta-V near escape velocity, or around
3
km/s.

The problem with putting HST outside low Earth orbit is that its pointing
system relies on geomagnetic torquers to desaturate its reaction wheels.
Move HST out of the Earth's magnetic field, and you've got to find some
other way to do that. Also, HST's comm system relies on TDRS, and
accessing
TDRS from well outside GEO is questionable at best.

Apparently, recovery of the
Hubble for placement in the Smithsonian is not possible, so I wanted
to put an alternative idea out for discussion.

Recovery of Hubble remains technically possible, but NASA has ground-ruled
it out for safety reasons.

How about attaching it to the ISS?
73 Roger ZR3RC

That's the idea I've been pushing, not only could it be serviced but also
controled from the ISS, have it maybe about a mile from it in same orbit.


--
"In this universe the night was falling,the shadows were lengthening
towards an east that would not know another dawn.
But elsewhere the stars were still young and the light of morning
lingered: and along the path he once had followed, man would one day go
again."

Arthur C. Clarke, The City & The Stars

SIAR
www.starlords.org
Telescope Buyers FAQ
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"Roger Conroy" wrote in message
...

..

How about attaching it to the ISS?
73 Roger ZR3RC




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Do you have any idea of what it would take to make such a significant shift
in orbits?



"Starlord" wrote in message
...
That's the idea I've been pushing, not only could it be serviced but also
controled from the ISS, have it maybe about a mile from it in same orbit.


--
"In this universe the night was falling,the shadows were lengthening
towards an east that would not know another dawn.
But elsewhere the stars were still young and the light of morning
lingered: and along the path he once had followed, man would one day go
again."

Arthur C. Clarke, The City & The Stars

SIAR
www.starlords.org
Telescope Buyers FAQ
http://home.inreach.com/starlord
World of Dahlias Slideshowv1.0 $10.00
for Windows machines. Email:



"Roger Conroy" wrote in message
...

.

How about attaching it to the ISS?
73 Roger ZR3RC




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"Starlord" wrote in message
...
That's the idea I've been pushing, not only could it be serviced but also
controled from the ISS, have it maybe about a mile from it in same orbit.


And what happens the first time you reboost ISS?

And not only that, except on a perfect sphere, with a separation of 1 mile
or so, that will gradually change over time.

"Greg D. Moore (Strider)" wrote:
"Starlord" wrote in message
...
That's the idea I've been pushing, not only could it be serviced but
also
controled from the ISS, have it maybe about a mile from it in same
orbit.


And what happens the first time you reboost ISS?

And not only that, except on a perfect sphere, with a separation of 1 mile
or so, that will gradually change over time.

Even over a "perfect sphere", the differential drag would move ISS and HST
apart rapidly.

Roger
--
Roger Balettie
former Flight Dynamics Officer
Space Shuttle Mission Control
http://www.balettie.com/

Boost it into Geo, it can still crosslink to Tedris, be further out of the
atmosphere and won't need fuel to keep from re-entering ...

"Greg D. Moore (Strider)" wrote in message
...

"Starlord" wrote in message
...
That's the idea I've been pushing, not only could it be serviced but
also
controled from the ISS, have it maybe about a mile from it in same
orbit.


And what happens the first time you reboost ISS?

And not only that, except on a perfect sphere, with a separation of 1 mile
or so, that will gradually change over time.

On Sun, 1 Feb 2004 20:19:44 +0200, "Roger Conroy"
wrote:


Recovery of Hubble remains technically possible, but NASA has ground-ruled
it out for safety reasons.

How about attaching it to the ISS?
73 Roger ZR3RC

We'd have to launch a Shuttle to go get Hubble. Bring it home. And
then launch it again on another Shuttle to the ISS. The fuel costs are
roughly comparable to sending a rocket up to it to change Hubble's
orbital inclination.

Then Hubble would have to contend with a relatively polluted
environment around ISS, which has rocket thrusters and many spacecraft
coming and going. And Hubble would have to be insulated somehow from
the vibration of humans and machines working inside the Station. And
somehow, Hubble would have to find a way to point itself irrespective
of what direction the Station is pointing.

Leaving it in orbit nearby is not practical, either. Hubble has no
propulsion system, so it would quickly drift away from ISS (which
performs semi-frequent orbit adjustment firings to maintain the
desired altitude.)

Brian

Brian Thorn wrote:
Then Hubble would have to contend with a relatively polluted
environment around ISS, which has rocket thrusters and many spacecraft
coming and going. And Hubble would have to be insulated somehow from
the vibration of humans and machines working inside the Station.

Forgetting economic reality for a moment, couldn't you tether a telescope to
the station with a cable that is a few kilometres long ? That would allow the
telescope to benefit from reboosts, while still being far enough away to avoid
the "pollution" near the station and with a tether long enough to attenuate
vibrations.

And at regular intervals, they could pull the telescope to the ISS where
changes could be done by ISS crews doing EVAs from Quest, and then push it
back to its tethered position. From a maintenance point of view, this would
end up costing a lot less since it woudln't require dedicated flights.

I realise at that the ISS altitude, such a telescope wouldn't provide the
ultimate in precision, but wouldn't it still be of useful to many scientists?