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 ; Mon, 19 Mar 90 01:25:50 -0500 (EST) Message-ID: Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Mon, 19 Mar 90 01:25:25 -0500 (EST) Subject: SPACE Digest V11 #162 SPACE Digest Volume 11 : Issue 162 Today's Topics: Spectra of Venus Atmosphere Re: Coilgun on a 747 - supplies to orbit at $20/lb? Re: Coilgun on a 747 - supplies to orbi Any HST-Schedule out there? Re: What was Challenger really up to? Re: Microgravity Research Drop Shuttle Escapes Use of HST guide-star sensor data for astrometry Challenger Report question Re: Resolving Power of Hubble Space Telescope ---------------------------------------------------------------------- Date: 17 Mar 90 19:11:45 GMT From: stretch.cs.mun.ca!chris2@uunet.uu.net (Chris Paulse) Subject: Spectra of Venus Atmosphere I'm a neophite when it comes to astronomy and astrophysics. Can anyone direct me towards a comprehensive introduction to the planetary atmospheres, particularly that of Venus. To be more specific, I'm looking for any available libraries of measured spectra of clouds on this planet (IR or UV). Any help would be appreciated. Chris Paulse Memorial U ------------------------------ Date: 18 Mar 90 07:56:58 GMT From: deimos.cis.ksu.edu!uafhp!uafcseg!bbs00447@uunet.uu.net (Patrick Spinler) Subject: Re: Coilgun on a 747 - supplies to orbit at $20/lb? I'm not a physicist or engineer (yet!) so some of my concepts may be frayed, but: A mass driver accelerates an armature + payload, then decelerates the armature, correct ? In this case (231ft length limitation) why bother deccelerating and saving the amature ? Simply eject it with the payload, and seperate them in flight. it would give you several more feet to accelerate your payload, and at a guess, the armature is cheap enough to waste, at least for a proof of concept. -- Pat Just a student pspinler%mkvax1.decnet@mkvax1.bitnet engineer in training pspinler@vax1.mankato.msus.edu [134.29.1.1] ------------------------------ Date: 18 Mar 90 17:39:59 GMT From: elroy.jpl.nasa.gov!usc!brutus.cs.uiuc.edu!ux1.cso.uiuc.edu!ux1.cso.uiuc.edu!m.cs.uiuc.edu!suna5!scott@decwrl.dec.com Subject: Re: Coilgun on a 747 - supplies to orbi /* Written 5:12 pm Mar 16, 1990 by steve@nuchat.UUCP in suna5:sci.space */ In article <8444@pt.cs.cmu.edu> vac@sam.cs.cmu.edu (Vincent Cate) writes: >Sounds like a coilgun on a high flying 747 should be a cheap way to ... >What are the hard parts of this type of approach? My guesses would be recoil and muzzle aerodynamics. Some of the momentum of the aircraft gets transfered to the projectile. Your projectile mass is limitted by the need to keep flying. There is a minimum size payload that will be useful, and multi-shot groups will be spread out over a whole lot of orbit. Fuel, for instance, really wants to be launched in large batches for a decent payload/container mass ratio and handling costs. And a 747 really doesn't fly that high. Maybe you could reengine one for operation where the air is rare, but in any case you'd start running out of lift and have to derate your mass calculations. You could get above a lot of atmosphere but you'd still be shooting through a lot, and now you'd have it shearing past your muzzle at 450 kts or whatever. I do know that the energy storage problem has a solution. A group at Texas A&M (if memory serves) has a railgun power supply "the size of a garbage can", using some kind of magnetic/electromechanical principle. The primary generators in the engines or your APUs place one limit on the firing rate, but once you charge the secondary generator you can pull megawatts out of it for the duration of the shot. A 747 is what, 200 ft long? Calculate the accelleration required to reach orbital velocity from, say, 1200 kts (air speed plus rotation, fudged for inclination and wind) in 200 ft. It won't be as kind to your payload as a longer ground based gun would be, but you may make it up in reduced heating for some payloads. Interesting idea, but I think you need a high-altitude, hypersonic aircraft for your first stage. A 747 just isn't enough better than a ground station to justify the cramped quarters, increased operation risk, and weight limits. One advantage it does have over a ground station is the ease with which it can match launch to window. Just fly to where the window is and yank the cord. -- Steve Nuchia South Coast Computing Services (713) 964-2462 "You have no scars on your face, and you cannot handle pressure." - Billy Joel /* End of text from suna5:sci.space */ ------------------------------ Date: 15 Mar 90 23:00:00 GMT From: snorkelwacker!ira.uka.de!smurf!gopnbg!altger!doitcr!nadia!delos!be@think.com (Bernd Ebach) Subject: Any HST-Schedule out there? Is there anybody out there knowing the schedule for the Hubble-Space- Tele-scope-Projects? I think there are about 100 People/Institutions waiting for their 'timeslice'. My special interest is about the 'Search-For-An-Extrasolar-Planetary- System-Projekt'. I heared, HST is meant to take a closer look at 53 Lightyears far 'Beta Pictoris' (where the hell can I find it this in- significant Star, which constellation?). I think responsible for this Project is Robert Brown. (Hi there, Rob, can you read me? Correct me if I'm wrong... ;^>) So, does anybody know how long I'm supposed to wait for the results of this event? Besides, the dates for the other Projects would be also nice to know. In gratitude for every hint... Bernd --- .signature (long) --- - believing in - / \ ...still extraterristrial live... \ / - searching for - | | | ...may it be - C - , - Si - or - WTHE* - based... | | | * (WTHE = What The Hell Ever) --- Disclaimer: Everything said above is my very own insignificant opinion. ------------- ___ Benediction: ...May this Message be seen by every host... --- Bernd Ebach, Blarerstr.1, 7ooo Stuttgart 5o ----------------------------------------------- be@nadia.UUCP ...{uunet;mcvax}!unido!nadia!be --- The End ------------------------------ Date: 18 Mar 90 19:28:07 GMT From: news-server.csri.toronto.edu!utgpu!watserv1!watdragon!watyew!jdnicoll@rutgers.edu (Brian or James) Subject: Re: What was Challenger really up to? Actually, the Challenger explosion was caused by a secret Canadian Death Ray satellite hidden in the SRB prelaunch (Thus the similarty to O-Ring failure). The True purpose of this satellite is, of course, classified, although it either pertains to defending our North West Passage from foreign invasion, or the Final Slution for our Grand Banks fishing difficulties. No counter evidence exists because, of course, They covered everything up perfectly, as They always do. In fact, this thread was *started* as the most recent step in the conspiracy, but Their funding just got cut, so it's ok to talk about it now. Sorry for the inconvinience. On behalf of The Men In Black, JDN PS: Your Vice President was Their doing, too. ------------------------------ Date: 18 Mar 90 20:29:09 GMT From: csusac!cs060241@ucdavis.ucdavis.edu (David Brock) Subject: Re: Microgravity Research Drop JP Aerospace is developing a Microgravity research vehicle. The vehicle is to be dropped from 10,000' and will be soft-landed. All interested parties are encouraged to contact: JP Aerospace, Inc. P.O. Box 2165 Fair Oaks, CA 95628 Free experiment space will be availible during testing drops for academic use. ------------------------------ X400-Trace: US*ATTMAIL*WIDE; arrival Sun, 18 Mar 90 20:10:58 -0500 action Relayed Date: Sun, 18 Mar 90 20:10:58 -0500 P1-Message-Id: US*ATTMAIL*WIDE; 5A031213361D0126-MTABWIDENER Ua-Content-Id: 5A031213361D0126 From: DXANDY%WIDENER.BITNET@vma.cc.cmu.edu Subject: Shuttle Escapes As a fan of single seater autoracing (Formula One, Indy and the like) I have seen plently of incidents involving high speed collisions and fire. The vast majority of these incidents involve no, or little, injury to the driver. Modern racing cars have carbon fibre tub in which the drivers sit. This tub provides a great deal of protection. It seems to me that if the Shuttle cockpit was designed in a similar fashion, it wouldn't matter if the rest of the shuttle had disintegrated, as long as the section containing the astronauts was relatively intact. A small drogue 'chute could prevent the cockpit section from tumbling wildly and slow it sufficiently to enable a survivable impact with the sea. If this approach was used, then you wouldn't need an array of fancy explosive bolts and associated equipment that could go off when you didn't need it. It seems that everyone wants to spend tremendous amounts of cash on massively difficult projects that have a miniscule chance of being useful. Why not try something simple for a change. Andy Greenshields [dxandy@widener.BITNET] ------------------------------ Date: 18 Mar 90 19:15:56 GMT From: mephisto!eedsp!chara!don@rutgers.edu (Donald J. Barry) Subject: Use of HST guide-star sensor data for astrometry Henry Spencer wrote that the guide-star tracking data from the HST was probably to be used for astrometry. It is -- the results will be of finer dimension than Hipparcos. The principal investigator is Otto Franz of Lowell Observatories, who is a collaborator with us in our Speckle Interferometry program. The guide-star lock data will be part of the "engineering science stream" relayed to earth, and will be archived and used to update and refine positions and precessional motion on the guide-stars, and also to search for duplicity among these objects. It's interesting to note that it was a major political battle just to ensure that the "engineering science" was separated from the "image science", so that the guide-star tracking data would not be held back for a year as part of an investigator's privileged datasets. There wasn't antipathy -- only bureaucratic inertia to overcome in making sure this data was separated and archived separately as part of a coherent record. -- Donald J. Barry (404) 651-2932 | don%chara@gatech.edu Center for High Angular Resolution Astronomy | President, Astronomical Georgia State University, Atlanta, GA 30303 | Society of the Atlantic ------------------------------ Date: Sun, 18 Mar 1990 22:17:30 PST From: "Mike Hewett" Subject: Challenger Report question I understand that Feynman wrote an addendum to the report that put stronger blame on the parties involved. I recently checked the Challenger Commission report out of the library and Feynman's addendum was not in it. Does anyone know where I could find it? If you haven't done it yet, I highly recommend reading the report. It has all the pertinent information, great pictures, and absolutely the best writing on a scientific subject that I have ever read (apologies to Stephen J. Gould, who formerly held the top spot on my list). I expected to spend a week wading through semi-coherent writing. In fact, I finished it in one evening and was spellbound the entire way through. Mike Hewett (hewett@sumex-aim.stanford.edu) ------------------------------ Date: 18 Mar 90 19:08:58 GMT From: mephisto!eedsp!chara!don@rutgers.edu (Donald J. Barry) Subject: Re: Resolving Power of Hubble Space Telescope Dan Briggs- Your point is well taken; I suppose we all are proud of our achievements in the field, and sometimes our claims take on a tone of superiority. Dan Fischer -- we are not studying stellar diameters -- I think you are confusing our speckle work with that of John Davis, et al. and the Narrabri Stellar Interferometer of the early 70's. The current speckle interferometry work is that of binary surveying -- we have spent some 150 observing nights on 4-m class instruments over the last ten years, making some 11,000 measures of binary stars. We are determining visual orbits to integrate with spectroscopic orbits to study mass functions, distance scales, and stellar evolution. The data is not processed with true imaging techniques, but rather limited imaging techniques that make use of the knowledge of the source as a collection of points. We have done true imaging, using modifications of "Shift and Add" (Bates, 1978), but have avoided to date Knox-Thomson because our camera is probably too noisy to give us good convergence. Until we have better reproducibility in this realm of processing, though, we won't publish -- we've got enough stellar papers in the works, anyway. (Do you feel as I do that too many people are publishing imaging results with poor reproducibility?) The array interferometer we consider likely to be funded within this year -- if so, we'll have first light through it by the beginning of 1994. The magnitude limits will not be so impressive as those you claim for the VLT and its cousins, but those numbers also assume workable development of adaptive technology which is still in its infancy. We are trying to be conservative until this exciting technology is better known. In any events, the instruments will complement one another -- the VLT array in light grasp, and the CHARA array in resolution. John Davis' proposed array in Sydney will yield yet greater resolution, but at lower (magnitude 8) limit. Although speckle masking permits easier phase identification, and makes reconstruction algorithms much more robust, it's good to remember that Fienup showed that almost every type of source can be reconstructed unambiguously from intensity information alone. I'll wait expectantly to hear the progress of the interferometric capability on ESO's new telescopes. This is an exciting, growing field for all of us. Best of luck with your progress. -- Donald J. Barry (404) 651-2932 | don%chara@gatech.edu Center for High Angular Resolution Astronomy | President, Astronomical Georgia State University, Atlanta, GA 30303 | Society of the Atlantic ------------------------------ End of SPACE Digest V11 #162 *******************