Return-path: X-Andrew-Authenticated-as: 7997;andrew.cmu.edu;Ted Anderson Received: from beak.andrew.cmu.edu via trymail for +dist+/afs/andrew.cmu.edu/usr11/tm2b/space/space.dl@andrew.cmu.edu (->+dist+/afs/andrew.cmu.edu/usr11/tm2b/space/space.dl) (->ota+space.digests) ID ; Wed, 4 Jul 1990 01:42:09 -0400 (EDT) Message-ID: Precedence: junk Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Wed, 4 Jul 1990 01:41:37 -0400 (EDT) Subject: SPACE Digest V12 #11 SPACE Digest Volume 12 : Issue 11 Today's Topics: Re: How to fix the HST Re: Reflections on Hubble and NASA Looking for a list of star names Nasa's budget Re: Aim For The Moon - model rocket contest realities of testing HST Hubble 2nd Generation Instruments Re: How to fix the HST Help with GMS images Inaccurate quotes (was: Re: More on NASA 91 Appropriation Vote) Re: What Spherical Aberration is Re: A report on Giotto's earth swingby Re: Reflections on Hubble and NASA Administrivia: Submissions to the SPACE Digest/sci.space should be mailed to space+@andrew.cmu.edu. Other mail, esp. [un]subscription notices, should be sent to space-request+@andrew.cmu.edu, or, if urgent, to tm2b+@andrew.cmu.edu ---------------------------------------------------------------------- Date: 3 Jul 90 08:22:18 GMT From: zaphod.mps.ohio-state.edu!samsung!munnari.oz.au!sirius.ucs.adelaide.edu.au!cs.ua.oz.au!francis@tut.cis.ohio-state.edu (Francis Vaughan) Subject: Re: How to fix the HST In article <1990Jul2.142932.7328@cbnewsh.att.com>, lmg@cbnewsh.att.com (lawrence.m.geary) writes: |>In article <1086@sirius.ucs.adelaide.edu.au> francis@chook.ua.oz.au (Francis Vaughan) writes: |>> |>>Build a robotic installation machine. The machine is latched to |> |>Minor problem: No one one earth knows how to do this yet, and it's unlikely |>that anyone will have one ready by 1993. I didn't mean some sort of AI, super amazing, all singing all dancing thing. Just a simple mechanical device that performs one and only one carefully designed and rehersed action. Move the corrector down the tube, swing under the baffle and then pull back into place. |>The idea of putting individual correctors on each instrument is better |>because the separate correctors can be optimized for the axial or off axis |>position of each instrument. A single, big corrector would probably ease |>problems with some of the instruments while making things worse for others |>off the optical axis. I'm not entierly convinced. I don't know enough about optics to really know. Other problems would be choice of material. It would need to be transparent to all of the wavelengths in use in all of the instrumentation. That rules out most glasses. Makes it difficult to make a multi-element design with different refractive indexes too. |>Two other problems with individual correctors, though. A) They'll have |>to replace ALL the instruments. I haven't heard that they are actually |>considering that, only the WFPC. B) You've got to put the new instruments |>back into their slots *just right* or they will be out of alignment. Exactly why I liked the idea of a single corrector. It is also (I think) a relativle simple fix from a technology point of view. No new technology would be needed, it should be a straight-forward design job. Also it may be possible to do something about the oscillations in the solar panels at the same time. Probably not cure but make it easier for the guidance system to cope. Francis Vaughan ------------------------------ Date: 3 Jul 90 08:16:06 GMT From: mcsun!ukc!axion!axion.bt.co.uk!apengell@uunet.uu.net (alan pengelly) Subject: Re: Reflections on Hubble and NASA Okay a mistake has been made, but it is worth remembering that HST is a novel concept, completely different to anything that has been done before. That good PR pictures will not be available for a while is a short term inconvenience. I believe when the programme is finished it will be viewed as a success. Keep at it NASA. ------------------------------ Date: 3 Jul 90 18:14:38 GMT From: agate!shelby!neon!news@ucbvax.Berkeley.EDU (Peter Commons) Subject: Looking for a list of star names I'm looking for a database of a couple hundred star names (e.g. Sirius, Altair, Deneb, ...) for use as part of a Macintosh application. If anybody has something of this sort online (in any form) it would be greatly appreciated. Please respond by email. -- |~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~| | Peter Commons "Zut, alors! I have meesed one!!!" | | commons@cs.stanford.edu | | Computer Science Department, Stanford University | ------------------------------ Date: 3 Jul 90 19:38:59 GMT From: thorin!grover!beckerd@mcnc.org (David Becker) Subject: Nasa's budget In article <9007030320.AA11960@NMSU.Edu> bwebber@NMSU.EDU writes: > >News flash: shuttle fleet grounded due to design error on h2 pump system >News flash: Hubble useless (almost) due to lack of testing on ground > >[Congress] will seize this as a chance to lay waste to the entire >U.S. space effort for the rest of the decade. Hmmm, looks like anti-space may become a popular political position. From the evening the news, the masses, and their representitives, hear 'Shuttle grounded' and 'Hubble useless'. How would NASA fare if Congress dropped NASA's Big Space items (ie. shuttle and Freedom)? Or cut flights to 1 or 2 a year (that is if the hardware doesn't force that anyway). Such trimming may not be as far fetched as it sounds since the shuttle is no longer relied on by DoD for snoop sats, the deficit is lingering and space is no longer a guaranteed American-Pride vote getter. Congress critters will be aware from now on that space can humiliate them just as well. Could cutting the Shuttle and cancelling Freedom actually help space explotation? Perhaps forcing NASA to make do with a much smaller allowance will stimulate the cost-effective launchers that all us netters are dying for. Or would the red tape survive as hardware is cut? David Becker Gotta love a machine that hangs on beckerd@cs.unc.edu your every word. ------------------------------ Date: 4 Jul 90 04:00:17 GMT From: bacchus.pa.dec.com!shlump.nac.dec.com!alien.enet.dec.com!mccarthy@decwrl.dec.com Subject: Re: Aim For The Moon - model rocket contest >In article <7154@scorn.sco.COM>, johnd@sco.COM (John DuBois) writes... >>In article <9677@pt.cs.cmu.edu> vac@sam.cs.cmu.edu (Vincent Cate) writes: >>+PS Has anyone calculated what a space shuttle solid rocket booster is on >>+ the "model" rocket scale? Seems like it will be something like 100 "Z"s >>+ but I don't have the data for the SRBs. >> >> I worked it out once; as I recall they're close to ZZ's. >> >> John DuBois The following calculations are based on lift off thrust, since that's the data I've got. Actual milage may vary, but bear in mind that a factor of two is only one letter off. 11,800,000 Newtons thrust x 132 Second burn ------------- 1,557,600,000 Newton-seconds total impulse / 1,280 Newton-seconds (size of J engine for reference) ------------- 1,216,875 Times J engine Log(2) 20.xx (20-21 steps beyond J engine) Puts the SRB at the low end of EE, if the scale goes: A B C ... Y Z AA BB CC ... -Brian ------------------------------ Date: 3 Jul 90 16:00:07 GMT From: mnetor!utzoo!henry@uunet.uu.net (Henry Spencer) Subject: realities of testing HST In article <9bCg02lm01JF01@JUTS.ccc.amdahl.com> ked01@ccc.amdahl.com (Kim DeVaughn) writes: >I usually agree with most everything you say Henry, but I have to differ on >this issue. When developing anything as sophisticated and unique as the >HST, one *must* count on good ol' Murphy lurking around *every* corner. And >plan accordingly... "Now, let me get this straight, Dr. HSTfella. You propose to spend seventy- five million dollars of the *taxpayers' money* on testing this telescope against the possibility of what you call `gross errors'. You've told us that such errors would occur only as a result of a major error or serious negligence by your contractors. Can you please tell us why you awarded a contract for several hundred million dollars to a contractor that you now feel you cannot trust?" Of course it's a good thing to be paranoid. The trouble is, it says in the book that this sort of thing can't happen, and when it says that in the book, people tend to be a wee bit unhappy about spending large amounts of money checking for the possibility. Too many people in this group are burning NASA in effigy for making a mistake they could easily have made themselves, had they been working under the same constraints. Hindsight is always 20-20. -- "Either NFS must be scrapped or NFS | Henry Spencer at U of Toronto Zoology must be changed." -John K. Ousterhout | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: 3 Jul 90 18:31:02 GMT From: frooz!cfa.HARVARD.EDU@husc6.harvard.edu (Steve Willner, OIR) Subject: Hubble 2nd Generation Instruments In article <396@cfa.HARVARD.EDU>, I was wrong about the acronyms for the second generation instruments. There are three instruments: WF/PC2: imager to replace Wide Field/Planetary Camera. NICMOS: infrared imager and spectrometer, cutoff wavelength 2.5 micron. (replacing some instrument not yet decided, but not WF/PC) STIS : spectrometer to replace (probably) Faint Object Spectrograph. (My understanding is that STIS duplicates most functions of High Resolution Spectrograph too, but I may be wrong. STIS can fit in any instrument bay except the one occupied by WF/PC.) WF/PC2 can compensate for the spherical aberration with a trivial change. NICMOS can compensate, but the changes look more complicated. STIS will probably have to add new optical components. Thanks to Bill Jefferys for setting me straight. ------------------------------------------------------------------------- Steve Willner Phone 617-495-7123 Bitnet: willner@cfa Cambridge, MA 02138 USA Internet: willner@cfa.harvard.edu ------------------------------ Date: 4 Jul 90 02:57:05 GMT From: network.ucsd.edu!celit!dave@ucsd.edu (Dave Smith) Subject: Re: How to fix the HST The Hubble mishap is not so much a really stupid mistake as a flaw in the whole procedure for building and deploying space-based devices. There are always problems that will slip through testing. No testing procedure will ever find all flaws and the procedures we use here on Earth reflect that. Deployment of a complicated device has to be an iterative process where you find and fix flaws. The whole Hubble problem would be a non-issue if we had a real presence in space and could just grind a new mirror and send an astronaut over to pop it in ("just" - I know the mirrors took forever to grind and they're not designed to be replaced on orbit). We've probably wasted more money over the years on ridiculous amounts of ground testing, devices which have been launched only to have some fatal flaw and the duplication of effort put into each device (does each device really need it's own orbital insertion computers, engines, etc?) then we would have to build a real space program. The reason the space program doesn't work well is because the approach it tries to take, of constructing perfect devices that work flawlessly the first time and therefore will not need fixing, does not fit with the way that humans work. That this approach has worked at all is a real testament to the engineers who put these things together. -- David L. Smith FPS Computing, San Diego ucsd!celerity!dave or dave@fps.com ***QUOTE CENSORED BY ORDER OF REV. MOM*** ------------------------------ Date: 3 Jul 90 02:45:21 GMT From: ccncsu!typhoon.atmos.colostate.edu!thorson@boulder.colorado.edu (Bill Thorson) Subject: Help with GMS images I am using some GMS satelite images and am having trouble decoding the time values. They encode the time as a floating point value for both image time and the epoch time for the orbital elements. The problem is that for an image in 1986 and about the 178th day the time fields have a value such as 46605.98125432. I don't know how to interpret this value. Someone suggested that it is probably daynumber.partoftheday. They also suggested that it may be the number of day in something like 'astrological' time. Can anyone give me an idea as the what this time field is and pointers to algorithms/procedures to decode them? #!/bin/sh #-----------------------------------------------------------------------# echo Bill Thorson thorson@typhoon.atmos.colostate.edu echo Dept of Atmospheric Science (303) 491-8339 echo Colorado State University echo Ft. Collins, CO 80523 Cray||Sun||Amiga -- I can't decide? #-----------------------------------------------------------------------# ------------------------------ Date: 3 Jul 90 09:26:56 GMT From: agate!agate!web@ucbvax.Berkeley.EDU (William Baxter) Subject: Inaccurate quotes (was: Re: More on NASA 91 Appropriation Vote) In article <5428@itivax.iti.org> aws@vax3.iti.org (Allen W. Sherzer) writes: >web@garnet.berkeley.edu (William Baxter) writes: >>[Andrew Cutler agrees with me that SEI a waste of money based on the >>90 day report] > Why did he >tell me in a phone conversation (roughly): "At least they are doing it >[SEI] right this time and taking a few years to study it and not just >jump in".? I asked Andy about this. He says he never made any such statement to you or to anyone else. In fact, he said that he has not discussed SEI with you at all. You really should quote people accurately. If you can't remember who said what, then check with them first. Misrepresenting Andy's position in order to support your argument ultimately undermines your own credibility. Tim Kyger, whose name is commonly associated with your own in this forum, also thinks that SEI is a waste of money. He calls it the "Staff Expansion Initiative." -- William Baxter ARPA: web@{garnet,brahms,math}.Berkeley.EDU UUCP: {sun,dual,decwrl,decvax,hplabs,...}!ucbvax!garnet!web ------------------------------ Date: 3 Jul 90 16:53:05 GMT From: mnetor!utzoo!henry@uunet.uu.net (Henry Spencer) Subject: Re: What Spherical Aberration is In article Mike.McManus@FtCollins.NCR.com (Mike McManus) writes: >So am I missing something? Assuming that (1) and (2) are known, what's the >problem with post-processing of images? The problem is that messed-up optics may just rearrange information, or they may actually lose information. For example, if the optics somehow were to focus all incoming light onto a single pixel in your camera, no amount of post-processing could ever recover a useful image from that one bright dot. In practice it's not that bad, but there are usually limits on how much of the mess can be post-processed out, especially when you don't know what the image is supposed to look like and you're working at the limits of the hardware. -- "Either NFS must be scrapped or NFS | Henry Spencer at U of Toronto Zoology must be changed." -John K. Ousterhout | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: 3 Jul 90 18:37:16 GMT From: ksr!clj@uunet.uu.net (Chris Jones) Subject: Re: A report on Giotto's earth swingby In article <1087@mpirbn.mpifr-bonn.mpg.de>, p515dfi@mpirbn (Daniel Fischer) writes: >It was an absolute first in space history: a spacecraft returning to earth from >the depths of the solar system, to receive a gravity assist for a new job. On >2 July 1990 at 10:01:18 Universal Time, precisely five years after its launch, >the European Giotto spacecraft approached earth to 22730 km over Australia, >raced past earth in a wide hyperbola with a speed of 6.3 kilometers per second, >and changed its orbit from one inside earth's to one outside - to meet comet >Grigg-Skjellerup on 10 Juli 1992 at 15:30 Universal Time +/- a few minutes. I suppose it comes down to nitpicking as to what is meant by "the depths of the solar system", but the International Cometary Explorer (ICE, nee IUE or something), which made a pass at comet G-Z (I'm not even going to try to remember how to spell it) came from its stationkeeping position near one of the Earth/Sun Lagrangian points (L1 I believe: the one between us) and made 5 flybys of the earth and/or moon to get its boost on its way to the comet. Good article though. Go Giotto! (And wouldn't it be interesting to see closeup what kind of shape that comet-beaten probe is in?) ------------------------------ Date: 3 Jul 90 22:21:53 GMT From: umich!sharkey!wyn386!wybbs!ken@CS.YALE.EDU (Ken ) Subject: Re: Reflections on Hubble and NASA In article <1990Jul3.081606.15178@axion.bt.co.uk> apengell@axion.bt.co.uk (alan pengelly) writes: > > Okay a mistake has been made, but it is worth remembering >that HST is a novel concept, completely different to anything >that has been done before. That good PR pictures will not >be available for a while is a short term inconvenience. I believe >when the programme is finished it will be viewed as a success. > Keep at it NASA. I wouldn't be too sure about that "it's never been done before statement." I seem to recall an article in Av Week or Defense News that said that there were some restrictions placed on the dissemenation of the technical details about Hubble. It seems the transport case for the Hubble bore a very strong resemblence to a certain classified military program. Assuming the appropriate safeguards were made, consider the capability of a Hubble pointed the other way around... Ken -- Ken Jongsma ken@wybbs.mi.org Smiths Industries ken%wybbs@sharkey.umich.edu Grand Rapids, Michigan ..sharkey.cc.umich.edu!wybbs!ken ------------------------------ End of SPACE Digest V12 #11 *******************