Death Sentence for the Hubble?

New York Times
February 13, 2005

EDITORIAL
Death Sentence for the Hubble?

Sean O'Keefe, the departing administrator of the National Aeronautics
and Space Administration, has yanked the agency's most important
scientific instrument off life support. His refusal to budget any funds
to service and upgrade the Hubble Space Telescope looks like the
petulant final act of an administrator who made a foolish decision and
then refused to back down in the face of withering criticism from
experts. The only uncertainty is whether the decision to let the Hubble
die prematurely was solely Mr. O'Keefe's or reflects the judgment of
higher-ups in the administration that servicing the Hubble would be a
diversion from the president's long-range program of space exploration.

The Hubble by all accounts has been one of the most productive
instruments in the history of science, largely because periodic
servicing missions by shuttle astronauts have extended its life and
upgraded its instruments. A fifth servicing mission had been planned,
and the new instruments already built, when the Columbia disaster
grounded the three remaining shuttles for repairs. Then, without any
warning, Mr. O'Keefe shocked scientists by announcing that the
servicing mission would be canceled for good because it would be too
risky.

Nothing, it seems, can budge him from that snap judgment. When a
dumbfounded Congress insisted that he seek advice from the National
Academy of Sciences, he reluctantly agreed, but made it clear that
nothing the academy said was apt to change his mind. He urged the
academy instead to focus on ways to extend Hubble's usefulness without
the help of astronauts. As it turned out, a panel of experts assembled
by the academy concluded that there was little chance the robotic
mission favored by Mr. O'Keefe could be mounted in time. The panel
urged instead that astronauts be sent to the rescue. It judged such a
flight only marginally more risky than a flight to the International
Space Station.

Undeterred, Mr. O'Keefe is now blaming the academy for sealing the
Hubble's doom. He still insists that a shuttle flight would be too
risky, mostly because there would be no place to take refuge should
problems arise, and now he complains that a robotic mission would be
impractical as well because the academy dismissed its prospects for
success. So he has wiped the budget clean of all rescue funds except
for a future robotic mission to ensure that Hubble falls out of orbit
safely.

Congress, which declared in a conference report last year that
servicing the Hubble should be one of NASA's highest priorities, needs
to order NASA to keep planning for a rescue mission. Some legislators
may wonder if a servicing mission is worth the effort, given recent
testimony by eminent scientists that they would be reluctant to see
NASA's science programs socked with $1 billion to $2 billion in charges
for the Hubble rescue - a huge sum that would disrupt other
high-priority programs - but would consider $300 million to $400
million acceptable. That bookkeeping issue is a diversion. The
refurbished shuttles will eventually return to flight, and the marginal
cost for sending one to the Hubble would not be prohibitive. Upgrading
the Hubble is probably the most important contribution today's
astronauts could make.

That's ok, the NGST will be many times better.

"MrPepper11" wrote in message
ups.com...
New York Times
February 13, 2005

EDITORIAL
Death Sentence for the Hubble?

Sean O'Keefe, the departing administrator of the National Aeronautics
and Space Administration, has yanked the agency's most important
scientific instrument off life support. His refusal to budget any funds
to service and upgrade the Hubble Space Telescope looks like the
petulant final act of an administrator who made a foolish decision and
then refused to back down in the face of withering criticism from
experts. The only uncertainty is whether the decision to let the Hubble
die prematurely was solely Mr. O'Keefe's or reflects the judgment of
higher-ups in the administration that servicing the Hubble would be a
diversion from the president's long-range program of space exploration.

The Hubble by all accounts has been one of the most productive
instruments in the history of science, largely because periodic
servicing missions by shuttle astronauts have extended its life and
upgraded its instruments. A fifth servicing mission had been planned,
and the new instruments already built, when the Columbia disaster
grounded the three remaining shuttles for repairs. Then, without any
warning, Mr. O'Keefe shocked scientists by announcing that the
servicing mission would be canceled for good because it would be too
risky.

Nothing, it seems, can budge him from that snap judgment. When a
dumbfounded Congress insisted that he seek advice from the National
Academy of Sciences, he reluctantly agreed, but made it clear that
nothing the academy said was apt to change his mind. He urged the
academy instead to focus on ways to extend Hubble's usefulness without
the help of astronauts. As it turned out, a panel of experts assembled
by the academy concluded that there was little chance the robotic
mission favored by Mr. O'Keefe could be mounted in time. The panel
urged instead that astronauts be sent to the rescue. It judged such a
flight only marginally more risky than a flight to the International
Space Station.

Undeterred, Mr. O'Keefe is now blaming the academy for sealing the
Hubble's doom. He still insists that a shuttle flight would be too
risky, mostly because there would be no place to take refuge should
problems arise, and now he complains that a robotic mission would be
impractical as well because the academy dismissed its prospects for
success. So he has wiped the budget clean of all rescue funds except
for a future robotic mission to ensure that Hubble falls out of orbit
safely.

Congress, which declared in a conference report last year that
servicing the Hubble should be one of NASA's highest priorities, needs
to order NASA to keep planning for a rescue mission. Some legislators
may wonder if a servicing mission is worth the effort, given recent
testimony by eminent scientists that they would be reluctant to see
NASA's science programs socked with $1 billion to $2 billion in charges
for the Hubble rescue - a huge sum that would disrupt other
high-priority programs - but would consider $300 million to $400
million acceptable. That bookkeeping issue is a diversion. The
refurbished shuttles will eventually return to flight, and the marginal
cost for sending one to the Hubble would not be prohibitive. Upgrading
the Hubble is probably the most important contribution today's
astronauts could make.

In article ,
Rodney Kelp wrote:
That's ok, the NGST will be many times better.

For some applications, not for all of them. (No UV capability in
particular.)

And that assumes that NGST actually flies.
--
"Think outside the box -- the box isn't our friend." | Henry Spencer
-- George Herbert |

If they don't make the NGST better, higher quality, and more capable what's
the point? Is there no progress any more?

"Henry Spencer" wrote in message
...
In article ,
Rodney Kelp wrote:
That's ok, the NGST will be many times better.

For some applications, not for all of them. (No UV capability in
particular.)

And that assumes that NGST actually flies.
--
"Think outside the box -- the box isn't our friend." | Henry Spencer
-- George Herbert |

Rodney Kelp wrote:
If they don't make the NGST better, higher quality, and more capable what's
the point? Is there no progress any more?

It will almost certainly be better, just not in the same areas
where HST currently operates.

Christopher M. Jones ) wrote:
: Rodney Kelp wrote:
: If they don't make the NGST better, higher quality, and more capable what's
: the point? Is there no progress any more?

: It will almost certainly be better, just not in the same areas
: where HST currently operates.

....which makes a case for keeping HST flying as long as possible.

Eric

In article ,
Rodney Kelp wrote:
That's ok, the NGST will be many times better.
For some applications, not for all of them. (No UV capability...

If they don't make the NGST better, higher quality, and more capable what's
the point? Is there no progress any more?

There was a decision, very early in the design process of NGST/JWST, that
all the interesting/fun astronomy was going to be happening in the IR, and
so there was no need for UV and little need for visible wavelengths.

This does have design implications: the longer wavelengths mean more
relaxed optical requirements, easier to meet with deployable mirrors and
such. (This is also why adaptive-optics systems on Earth-based telescopes
mostly work in the IR at present.) In other words, if you're willing to
build a telescope that's IR-only, you can make it rather bigger with the
same technology... and that means more light-gathering power and better
ability to study very faint, very distant objects.

So, it wasn't a grossly unreasonable tradeoff; it had important virtues.
It may have been the wrong decision but it wasn't stupid.

But there *are* astronomers who do think it was the wrong decision.
--
"Think outside the box -- the box isn't our friend." | Henry Spencer
-- George Herbert |

In article ,
(Henry Spencer) wrote:

There was a decision, very early in the design process of NGST/JWST, that
all the interesting/fun astronomy was going to be happening in the IR, and
so there was no need for UV and little need for visible wavelengths.

This does have design implications: the longer wavelengths mean more
relaxed optical requirements, easier to meet with deployable mirrors and
such. (This is also why adaptive-optics systems on Earth-based telescopes
mostly work in the IR at present.) In other words, if you're willing to
build a telescope that's IR-only, you can make it rather bigger with the
same technology... and that means more light-gathering power and better
ability to study very faint, very distant objects.

So, it wasn't a grossly unreasonable tradeoff; it had important virtues.
It may have been the wrong decision but it wasn't stupid.

But there *are* astronomers who do think it was the wrong decision.

This makes the Hubble Origins Probe more appealing as an alternative to
an HST repair mission: http://www.pha.jhu.edu/hop/

In article ,
(Henry Spencer) writes:
There was a decision, very early in the design process of NGST/JWST, that
all the interesting/fun astronomy was going to be happening in the IR, and
so there was no need for UV and little need for visible wavelengths.

That's probably not the clearest way to say what happened, and in
particular the word "all" is misleading. It would be better to say
that the highest scientific priority for JWST (then NGST) was deemed
to be study of the very distant Universe and in particular the "epoch
of reionization," now thought to have happened at redshifts between 6
and 20. No one expects any one instrument to do all possible
observations, and it is always necessary to set priorities.

Given the chosen scientific goal, one needs to observe in the
infrared, and one needs a very large aperture both to obtain adequate
angular resolution and to have enough collecting area.

This does have design implications: the longer wavelengths mean more
relaxed optical requirements, easier to meet with deployable mirrors and
such. (This is also why adaptive-optics systems on Earth-based telescopes
mostly work in the IR at present.) In other words, if you're willing to
build a telescope that's IR-only, you can make it rather bigger with the
same technology... and that means more light-gathering power and better
ability to study very faint, very distant objects.

Exactly so. Or another way to put it: if you have a budget, which
would you rather have, maximum collecting area or a superb surface
figure? Given the scientific goal for JWST, more collecting area is
obvious.

So, it wasn't a grossly unreasonable tradeoff; it had important virtues.
It may have been the wrong decision but it wasn't stupid.

That's putting it mildly. Given the scientific goal, any other
tradeoff would have been a clear mistake. Of course one can always
argue about what the scientific goal should have been. If one wants
to study the composition of nearby diffuse gas clouds, for example,
ultraviolet is the way to go. On the whole, I think there was and is
wide agreement that studying the reionization epoch is the highest
priority, but this is an opinion or judgment, not something that can
be said to be right or wrong.

For studying the stellar content of galaxies, we can argue a bit, but
rest wavelengths between 0.5 and 3 microns are the right ballpark.
Multiply these numbers by 7 to 21 (1+z for the estimated redshift of
reionization), and you get observed wavelengths of 3.5 to 60 microns.
In fact, the long wavelength cutoff of JWST will be limited by
detector technology to about 28 microns. (And besides, z=20 probably
isn't very realistic anyway even with the original 8-meter mirror,
let alone the currently-planned 6.5-meter.) The short wavelength
limit will be extended below 1 micron because that's relatively cheap
and easy to add, but the image quality will be less than perfect at
these wavelengths.

--
Steve Willner Phone 617-495-7123
Cambridge, MA 02138 USA
(Please email your reply if you want to be sure I see it; include a
valid Reply-To address to receive an acknowledgement. Commercial
email may be sent to your ISP.)

In article ,
Rodney Kelp wrote:
That's ok, the NGST will be many times better.

Not if you do optical or UV work.