OT: Save the Hubble Telescope

[John Woodgate]

I read in sci.electronics.design that Tom Del Rosso
ws.ops.worldnet.att.net>) about 'OT: Save the Hubble Telescope', on Wed,
11 Feb 2004:

In John Woodgate typed:

Why more fuel to come back?

Mars has more mass than Moon.

 

[SioL]

Because taking enough fuel to come back requires taking *much* more
fuel to get it there.

Clifford.

Not really. They've found frozen water there. That's what the whole idea of going there
is based on.

Siol

 

[Russell Shaw]

You don't need as much to get there as you do to come back. But,
depending on how long you are prepared to take to get there, you might
need less than for an Earth-Moon-Earth trip. The Earth has a much deeper
gravity well than either Moon or Mars.

Any manned space missions other than satellite maintenance is stupid.

Manned space missions without compact fusion power sources is unviable
and stupid.

A ton of valuable spinnoffs in AI, computer hardware, and robotics is
the main benefit of robotic missions.

All the money saved by dumping the ISS is better put into new fusion
power research programs.

This will never happen with politicians backed by oil money.

 

[Tom Del Rosso]

In John Woodgate typed:

Mars has more mass than Moon.

Ah! I'm stuck in my taking-off-from-Earth mode of thinking.

 

[Zak]

Not really. They've found frozen water there. That's what the whole idea of going there
is based on.

So you build a water powered rocket? Oh, you elelectrolyze it to form
hydrogen and oxygen. Neat. It takes a lot of energy... and a lot of
solar panels... or something nuclear of substantial size - and a lot of
time in any case.


Thomas

 

[SioL]

So you build a water powered rocket? Oh, you elelectrolyze it to form
hydrogen and oxygen. Neat. It takes a lot of energy... and a lot of
solar panels... or something nuclear of substantial size - and a lot of
time in any case.
Thomas

Yep, but that's the idea, I've read about it. They'd be staying there for a while
until they separated enough water into hydrogen and oxygen.

Hey, even the new car-sized mars rovers, scheduled for 2009, are supposed
to have nuclear power. Interestingly, these are supposed to be landed by a crane
from a hovering craft. The bubblewrap is not cutting it anymore.

Anyone got a link for that? I've read about it recently.

SioL

 

[Tom Del Rosso]

In SioL typed:

Hey, even the new car-sized mars rovers, scheduled for 2009, are
supposed
to have nuclear power. Interestingly, these are supposed to be landed
by a crane
from a hovering craft. The bubblewrap is not cutting it anymore.

I don't see why they have to drop the airbags from 20 meters. Why not
slow to a stop and then cut half the retros instead of all of them, or
slow to a stop at just above the ground? Can't the RADAR give the
distance reliably?

 

[SioL]

In SioL typed:

I don't see why they have to drop the airbags from 20 meters. Why not
slow to a stop and then cut half the retros instead of all of them, or
slow to a stop at just above the ground? Can't the RADAR give the
distance reliably?

I don't know, I guess they've figured out its more reliable this way after all
the lost missions in the past.

Siol

 

[Mikkel Breiler]

Why not
use an orbiting staging area, maybe at a Lagrange point, but it could be
in any kind of high orbit.

Because artificial gravity sucks around dinnertime.

Mikkel

 

[Winfield Hill]

Mikkel Breiler wrote...

Because artificial gravity sucks around dinnertime.

The Hubble Space Telescope's relatively low orbit (600km, higher
than the space station, but still subject to atmospheric drag) is
due to the cost of boosting it higher. Even a geostationary orbit
(60x higher at 35786km) is impractical, given the HST's high mass
(11,000kg = 24,500#). A Lagrange point orbit (the moon's distance)
would be much more difficult. (But read about JWST below.)

The HST has gotten a boost most every servicing trip, but the loss
of the Columbia caused the next scheduled trip to be canceled.

http://hubblesite.org/newscenter/newsdesk/future/

"Servicing Mission 4 had a series of jobs to perform. Astronauts
would have boosted Hubble into a higher orbit, a standard task that
helps keep Hubble from spiraling too close to the Earth and re-
entering the atmosphere. They would have replaced a fine guidance
sensor, which helps point the telescope; placed protective "blankets"
on top of torn insulation; and installed [powerful] new instruments:
Wide Field Camera 3 [snip] and Cosmic Origins Spectrograph [snip].

"Astronauts' last visit to Hubble, Servicing Mission 3B, was in 2002.
During that mission, astronauts put Hubble in shape for the future
by installing new solar panels, the powerful Advanced Camera for
Surveys and a new cooling system for NICMOS. They also replaced a
wheel reaction assembly that helps point the telescope and re-boosted
Hubble's orbit."

The Hubble Space Telescope has massive support among both scientists
and the public. Last July the National Academy of Sciences issued a
report recommending saving the HST, and that accomplishing the tasks
(which were scheduled for Service Mission 4) be a high NASA priority,
http://hubblesite.org/newscenter/newsdesk/future/nas_interim.html

The HST was launched in 1990 with a planned 15-year life (i.e. 2005),
later extended to 20 years (2010), and it could perhaps perform much
longer with service.

A replacement, the James Webb Space Telescope, is planned for 2011,
but, well ... http://jwstsite.stsci.edu/ Although the JWST will be
a larger telescope than the HST, it's expected to be half the weight.
Also, there's this on the website: "Mission planners want to place
the JWST in an orbit well beyond Earth's Moon at a place called the
Second Lagrange Point (L2) — a challenging orbit for a NASA space
astronomy mission." Hah! We'll have to wait and see what happens.

 

[Ken Smith]

Because artificial gravity sucks around dinnertime.

As space craft go, the shuttle stinks. It can't reach a high orbit.
This means that if Hubble is to be serviced, it must be in low orbit.
The science community is paying a high price for the bad choices that went
together to make the shuttle program.

Q: Why does the shuttle exist?
A: To go to the space station.
Q: Why does the space station exist?
A: To give the shuttle a place to go.

 

[dd]

A replacement, the James Webb Space Telescope, is planned for 2011,
but, well ... http://jwstsite.stsci.edu/ Although the JWST will be
a larger telescope than the HST, it's expected to be half the weight.
Also, there's this on the website: "Mission planners want to place
the JWST in an orbit well beyond Earth's Moon at a place called the
Second Lagrange Point (L2) — a challenging orbit for a NASA space
astronomy mission." Hah! We'll have to wait and see what happens.

The value of that mass with its value in the low orbit now! should not
be underestimated.
A future telescope is always uncertain .
I note that spinning gyros are a major source of lifetime limit.
Hemispherical vibrating gyros have now been space tested and are hardly
inferior in drift performance they could be retro fitted in any new
update.
Time to upgrade by any means.

 

[Rich Grise]

The value of that mass with its value in the low orbit now! should not be
underestimated.
A future telescope is always uncertain . I note that spinning gyros are a
major source of lifetime limit. Hemispherical vibrating gyros have now
been space tested and are hardly inferior in drift performance they could
be retro fitted in any new update.
Time to upgrade by any means.

Now that some serious money is interested in civilian space travel,
how much do you think it would cost to periodically ship some supplies
and stuff up to Hubble?

It sure sounds like Virgin Galactic intends to go to orbit with a craft
that has some respectable capability - it's gotta be cheaper than a
shuttle flight!

Cheers!
Rich

 

[Winfield Hill]

Rich Grise wrote...

Now that some serious money is interested in civilian space travel,
how much do you think it would cost to periodically ship some supplies
and stuff up to Hubble?

It sure sounds like Virgin Galactic intends to go to orbit with a craft
that has some respectable capability - it's gotta be cheaper than a
shuttle flight!

I'm sorry, but the maximum velocity achieved by a 3-minute weightless
flight is a _small_ fraction of that needed to obtain even a low orbit.

 

[Rich Grise]

Rich Grise wrote...

I'm sorry, but the maximum velocity achieved by a 3-minute weightless
flight is a _small_ fraction of that needed to obtain even a low orbit.

Yeah, I knew that. <blush> Must be my overoptimistic selective memory. ;-)
I remembered they were already selling tickets to a suborbital ride, and
I've let my wishful thinking run away with me. ;-)

And, of course, it's no secret that I have a fantasy of dramatically
slashing military spending, to spend on research and exploration and
that sort of fun stuff.

One time, while one of the Mars missions was hot - I think it was the
first one with the air bags - there was a call-in show on CNN or
something, with people talking about NASA and funding and stuff. I
actually got through! So I asked, on live cable TV, "Is it not true
that the money saved by _not_ buying, say, _one_ nuclear-missile-
carrying submarine, would pay NASA's entire budget, ever?" Or words
to that effect.

And they were almost unanimous, like, well of course.

So I really hope the government gets their priorities straightened out,
one way or the other.

Thanks,
Rich


Thanks!
Rich