Time to scrap the Hubble telescope?

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

If so, and since HST shows no sign of slowing down in its
production of outstanding science, why not consider launching a
modernized but essentially similar Hubble-2? Doubtless LockMart
would be glad of the business, and might even have some spare KH-11
hardware around that could be used.

In a word: Money.

Well, yes. But say that money were an explicit constraint: could a
much-like-Hubble Hubble-2 be built and launched in five years for
two to four gigabucks total, we-really-mean-it-do-not-exceed cost?
Say the price of a half to one STS launch per year for those five
years? It doesn't seem too absurd for an agency that is funded at
$15G/yr to scrounge up that kind of money for a kind instrument that
has been proven to produce staggeringly wonderful results and shows
no signs of stopping.

"Greg D. Moore (Strider)" wrote:
All the more reason to dig out the Kodak mirror, grab the old equipment
already removed from Hubble and build a Hubble II. Toss it into a high
orbit, assume once it breaks it breaks and now you've got another world
class sat for a miniscule cost of the original. The bigger problem I think
would be funding the ground operations after launch.

Bad idea. Hubble might be one of a kind and highly valuable now,
but it's design is grossly obsolete, even with updated
instruments. The Nexus side / sub project (which, sadly I think,
got axed) of NGST showed a better and cheaper way to get Hubble
class optics. Hubble was designed and built at a time of great
change in telescope systems, especially optics. The type of
monolithic mirror used on Hubble has been surpassed by perhaps
more than one full generation of optical designs (depending on
how you count). If they were redesigning a spacecraft today to
match Hubble's capabilities it would be lighter and cheaper and
probably much more capable even in the same basic package. It's
almost too bad that ESA hasn't succumbed to the classic "well if
they're doing it, we're doing it!" behavior and designed a
Hubble class next generation space telescope on the cheap (and
it could be done, easily). But I suppose they haven't because
they've already got an in with NGST / JWST and they've still got
a decent stake in Hubble, while it lasts.


Oh, and the mirror is a relatively minor cost of any observatory,
the big costs are in instrumentation and other systems. It's
easy to think "mirror = observatory", but that's not the case
and simply having a free mirror around would not really
substantially decrease the cost of a new space telescope. In
fact, the needs of having to design the telescope around the
"free mirror" would probably cost more than a from scratch
design.

"Alex Terrell" wrote:
My specific interest is more composition and orbit determination for
resourc e usage, rather than space guard. Would the spectral "sorting"
enable any of that?

The aim would also not be to find all NEOs within a region, but to
randomly identify a few that could then be analysed for material
composition and rendezvous profile, a few y

Here's the funny part. Hubble has a lot of decent capability
for multi-spectral imaging and even some basic spectrometers,
but spectroscopy is much more forgiving, generally, to things
like atmospheric disturbance. So it really pays just to have
the biggest light-bucket you can get, and that means, for now,
ground based telescopes. And indeed, spectroscopy is where
the big ground based telescopes excell. That's why things
like the cosmological supernova searches, which nailed down the
accelerating expansion of the universe, or doppler velocity
planet searches are done using big ground based telescopes
(both are spectroscopic studies).

"Allen Thomson" wrote:
Well, yes. But say that money were an explicit constraint: could a
much-like-Hubble Hubble-2 be built and launched in five years for
two to four gigabucks total, we-really-mean-it-do-not-exceed cost?
Say the price of a half to one STS launch per year for those five
years? It doesn't seem too absurd for an agency that is funded at
$15G/yr to scrounge up that kind of money for a kind instrument that
has been proven to produce staggeringly wonderful results and shows
no signs of stopping.

You're far behind the times. NGST won't cost near that
much, even if it overruns its budget by a huge margin.
And really a new Hubble replacement could just about fit
within one of those new fangled New Frontiers mission
budgets (depending on design, of course).

This is one of the classic problems of publically funded
science. There's often a tendency to chase after the
"edge" and eschew the fundamentals or "retreading" what's
been done, even when you can do so at relatively little
cost in comparison.

"Devlin" wrote in message
...
In article , Allen
Thomson wrote:

One thing that I wonder about is the wisdom of viewing NGST (JWST?)
as a replacement for Hubble, rather than as a separate instrument
intended for different, if complementary tasks. IIRC, NGST isn't
meant to operate at wavelengths shorter than 600 nm, which doesn't
even include all of the visible part of the spectrum, let alone the
UV.

If so, and since HST shows no sign of slowing down in its
production of outstanding science, why not consider launching a
modernized but essentially similar Hubble-2? Doubtless LockMart
would be glad of the business, and might even have some spare KH-11
hardware around that could be used.

What's planned for after JWST? It's only planned to last 5-10 years, so
wouldn't its successor need to be on the drawing boards soon?

Some information he
http://www.aura-astronomy.org/hsl/

In article , "Christopher M.
Jones" wrote:

"Greg D. Moore (Strider)" wrote:
All the more reason to dig out the Kodak mirror, grab the old equipment
already removed from Hubble and build a Hubble II. Toss it into a high
orbit, assume once it breaks it breaks and now you've got another world
class sat for a miniscule cost of the original. The bigger problem I think
would be funding the ground operations after launch.

Bad idea. Hubble might be one of a kind and highly valuable now,
but it's design is grossly obsolete, even with updated
instruments. The Nexus side / sub project (which, sadly I think,
got axed) of NGST showed a better and cheaper way to get Hubble
class optics. Hubble was designed and built at a time of great
change in telescope systems, especially optics. The type of
monolithic mirror used on Hubble has been surpassed by perhaps
more than one full generation of optical designs (depending on
how you count). If they were redesigning a spacecraft today to
match Hubble's capabilities it would be lighter and cheaper and
probably much more capable even in the same basic package.

That's all very well and true, but until a new gee-whiz replacement
actually gets built and flown any superiority the replacement might have
over Hubble is pretty much irrelevant. You can't do useful things with a
mission that only exists on paper! If nobody is prepared to fund a Hubble
2 that pretty leaves two options: making do with the hardware you already
have in space, obsolete or not, or doing without Hubble *and* any
replacement.

--
Stephen Souter

http://www.edfac.usyd.edu.au/staff/souters/

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

If so, and since HST shows no sign of slowing down in its
production of outstanding science, why not consider launching a
modernized but essentially similar Hubble-2? Doubtless LockMart
would be glad of the business, and might even have some spare KH-11
hardware around that could be used.

In a word: Money.

Well, yes. But say that money were an explicit constraint: could a
much-like-Hubble Hubble-2 be built and launched in five years for
two to four gigabucks total, we-really-mean-it-do-not-exceed cost?
Say the price of a half to one STS launch per year for those five
years? It doesn't seem too absurd for an agency that is funded at
$15G/yr to scrounge up that kind of money for a kind instrument that
has been proven to produce staggeringly wonderful results and shows
no signs of stopping.

There seems to be a consensus among folks who build these things that
one could build and launch a Hubble-class (2-2.5m) telescope with
acquisition/guiding plus a single science instrument for the
surprisingly small level of 500M (some proposals come in well
below by taking advantage of special opportunities, but NDRs
probably mean I can't be any more specific). For example, the
optical systems are now basically admitted to be reconnaissance-satellite
clones.

This only translates into "doable for NASA" if one can make a case for
a new kind of science (wide field, IR sensitivity, multispectral
capability). This is an agency that has shown little compunction in
the past about shutting down functional satellites past their
primary missions. Actually, given resources in high demand and
new and powerful science capabilities coming along (i.e. JWST vs HST),
it can't help being a tough decision.

Note to Ed Weiler - guess that makes me a Hubble hugger...

Bill Keel