Hubble (albatross)
Greg Moore
>Did you hear about the Hubble?
>
Yeah... He's sorta famous. Even has a telescope named after him.
Oh... you mean the telescope. ;-)
>One of our astronomers (she has time on the Hubble) learned that the
>army trained one of it's high-resolution imaging satellites on the
>Hubble Scope, and found it flapping it's solar panels like a bird.
>
This has been known for a while. As far as I know (Henry?)
this was first observed when it crossed the terminator and is (was?)
believed to be caused by thermal contraction and expansion.
There was some talk about fixing it in '93 with new panels, but
I'd heard recently that this may not be done due to budget
restraints and the fact that NASA wants to limit EVA time and
make sure the fix the aberration. Right now they have some
comptuer fixes to minimize the problem.
>It's not reboosting, BTW. No-one knows what will become of it.
>
I'm not sure what you mean by reboosting. It has no active
means of changing its orbit. That is another reason for the
'93 mission, for the shuttle to reboost it.
>Anyone heard about this? Is it only a rumor? I doubt it, since the
>lady that I heard it from hasn't much of a sense of humor about this
>kind of thing.
>
Well, it's not a rumor, nor is it news. (well, it may be news to
some people, but nothing that not's known or being covered up.
Though the Army bird angle is the first I've heard.)
>Tommy Mac
<------------------------------------------------------------------------->
Carpe Diem Greg_d...@mts.rpi.edu
Greg_d...@acm.rpi.edu
"All that is gold does not glitter." Strider_of_...@mts.rpi.edu
Tom McWilliams
One of our astronomers (she has time on the Hubble) learned that the
army trained one of it's high-resolution imaging satellites on the
Hubble Scope, and found it flapping it's solar panels like a bird.
It's not reboosting, BTW. No-one knows what will become of it.
Anyone heard about this? Is it only a rumor? I doubt it, since the
lady that I heard it from hasn't much of a sense of humor about this
kind of thing.
Tommy Mac
Tarl Neustaedter
transitioning from shadow to sunlight as it goes around the earth.
This vibration is pretty awful for imaging, but would probably not
be visible to you if you were standing next to it.
Any story about a military satellite watching the hubble's solar panels
"flap like a bird" is either a joke or a hoax.
--
Tarl Neustaedter ta...@vos.stratus.com
Marlboro, Mass. Stratus Computer
Disclaimer: My employer is not responsible for my opinions.
Douglas Creel
>
>One of our astronomers (she has time on the Hubble) learned that the
>army trained one of it's high-resolution imaging satellites on the
>Hubble Scope, and found it flapping it's solar panels like a bird.
>
This sounds doubtful right from the start of your description. Imaging
reconnaisance satellites (assuming the Army is one of the branches of the
armed services that even has one, more likely the Air Force) are in low
Earth orbit. For one satellite moving at 17,000 mph to take a picture (a
motion picture no less!) of another satellite moving at a similar velocity is
totally ridiculous. The military also makes it a policy of not disclosing what
it takes pictures of. Indeed, the HST was having vibration problems with its
solar panels as the s/c passed between night and day on each orbit, but modified
software on board has been able to handle this, although it has severely taxed
the Hubbles computers.
>It's not reboosting, BTW. No-one knows what will become of it.
>
The Hubble will be reboosted by the shuttle, that has ALWAYS been the plan.
>Anyone heard about this? Is it only a rumor? I doubt it, since the
>lady that I heard it from hasn't much of a sense of humor about this
>kind of thing.
>
Recheck your source's source. I've heard far more ridiculous rumors than this
from supposedly "reliable" sources which turned out to be completely false.
Douglas D. Creel
Mars Observer Navigation Team
Jet Propulsion Laboratory
Henry Spencer
> This has been known for a while. As far as I know (Henry?)
>this was first observed when it crossed the terminator and is (was?)
>believed to be caused by thermal contraction and expansion.
Yeah, the clever lightweight-and-reversible support scheme for the solar
arrays appears to have a thermal expansion/contraction problem. Last I
heard, they still weren't sure how that slipped through testing.
--
Lightweight protocols? TCP/IP *is* | Henry Spencer @ U of Toronto Zoology
lightweight already; just look at OSI. | he...@zoo.toronto.edu utzoo!henry
Henry Spencer
>army trained one of it's high-resolution imaging satellites on the
>Hubble Scope, and found it flapping it's solar panels like a bird.
Methinks somebody is mistaken or pulling your leg. For one thing, the
Army doesn't have hi-res imaging satellites -- those belong to the National
Reconnaissance Office and are operated by the Air Force. For another, the
solar-array "flapping" problem has been known for quite a while. For a
third, although you could see it if you watched carefully from nearby, it
would not be particularly noticeable from afar; the motion is large enough
to trouble the astronomers but not big in absolute terms.
>It's not reboosting, BTW. No-one knows what will become of it.
Hubble has never had any on-board reboost capability. In fact it has no
rocket engines at all, partly to avoid any possibility of contaminating
the optics with exhaust.
Daniel Delvalle
Ok, it's true...while not exactly like a bird, the panals are doing a bit
of flapping.
Seems that the Great minds that put this project through testing, did not
go far enough in their investigations.
So now, every time the Hubble's panals go from night to Day light, the Thermal
contractions cause the panals to wobble...and of course, from Day to night.
(From what I've read, the motion just keeps building up with every pass.)
And if this weren't bad enough, seems that whenever they send a command to
rotate the instrument carousel, it's motion also throws the Hubble off a
bit. They recently tried to counteract this effect with a software fix, but
the program they "patched" in, only made things worse and it had to be
removed.
Seems that the occilations are happening in three "wavelenghts?", and when
they tried to dampen one, with the software, it only reinforced the other
two.
"""""
". ."
Kizn. l
(-)
Mike Ungerman
Why have we not seen any more progress reports on Hubble on this newsfeed?
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Daniel Fischer
>Why have we not seen any more progress reports on Hubble on this newsfeed?
future (most of the Status Reports here dealt with problems and disasters),
but a working observatory! There was already a spectacular collection of early
astronomical papers in the Astrophysical Journal in March and another one with
even more striking things is coming soon; also, a major story has just appeared
in last weeks Nature. HST is like IUE now: it's just doing its work.
mil...@rcf.rsmas.miami.edu
Your comment that "the HST is no longer considered a spacecraft with uncertain
future" just doesn't square with reality. The Miami Herald published an article
today (7/31/91), which said in essence that it will be most likely be
necessary to mount an emergency expedition to fix Hubble's failing gyros
sometime during 1992. Two out of six have already failed and a third is
showing signs of failing soon. The gyros are now not expected to hang in there
until the scheduled 1993 flight on which the fix for the optical problem was
supposed to be implemented. The real rub is that the optical fix apparently
will not become available before the gyro-related flight must happen and, since
there are funds to cover only one flight, the optics will not get fixed. I
guess the reasoning is that it is better to have a myopic Hubble than a
tumbling Hubble. A separate but perhaps no less serious issue is that the
"wing-flapping" is probably causing metal fatigue which may compromise the
power system.
In summary, I suspect that the reason we are not seeing updates on Hubble is
that, despite having generated some useful data, it is a continuing
embarassment to the folks in charge.
Let's hear from some people in the know (e.g., NASA, contractors) about details
of the problems mentioned above.
-------------------------------------------------------------------------------
Jerry L. Miller /\ Rosenstiel School of Marine and Atmospheric Science
#\ o O \/ /\ University of Miami
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/ / o O \/ Miami, FL 33149 USA
Phone: (305) 361-4762 INTERNET: mil...@rcf.rsmas.miami.edu
Shireen Gonzaga
>
> In summary, I suspect that the reason we are not seeing updates on Hubble is
> that, despite having generated some useful data, it is a continuing
> embarassment to the folks in charge.
>
> Let's hear from some people in the know (e.g., NASA, contractors) about details
> of the problems mentioned above.
>
by the Space Telescope Science Institute. If you're interested in what
the status of the observatory is, what it has been observing lately,
what it has already done, instrument updates and a whole lot more,
just "ftp stsci.edu" and access it as user anonymous. There is a
README file to tell you how to look for information. It's very useful,
even for us who work here!
--
______________________________________________________________________________
Shireen Gonzaga/Science Planning Branch/Space Telescope Science Institute/
3700 San Martin Dr./Baltimore/MD21218/tel301-338-4412/ARPA shi...@stsci.edu
SPAN SCIVAX::GONZAGA
Robert David Bunge
>
>that, despite having generated some useful data, it is a continuing
>embarassment to the folks in charge.
>
>Let's hear from some people in the know (e.g., NASA, contractors) about details
>of the problems mentioned above.
Daily reports on HST can be read on the STScI Electronic Information Service
(STEIS) at FTP stsci.edu in the stsci/hst_news/ directory. These include
number and types of observations made that day along with discussions and
comments about problems. At times can be interesting to read. Perhaps there
is a way to get these posted to the net, much like Ron (bless his heart)
does Magellan and other spacecraft.
Bob Bunge
bu...@wam.umd.edu