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 ; Tue, 19 Jun 1990 01:45:18 -0400 (EDT) Message-ID: Precedence: junk Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Tue, 19 Jun 1990 01:44:42 -0400 (EDT) Subject: SPACE Digest V11 #539 SPACE Digest Volume 11 : Issue 539 Today's Topics: Re: Weather Satellite Photos Re: US/Soviet Planetary Activity (was Re: Manned mission to Venus) Challenger accident (Was: Re: 10 psi overpressure) Re: Model rocket contest Re: Aim For The Moon - model rocket contest CRRES mission briefing and spacecraft showing at KSC on June 22 (Forwarded) Re: 10 psi overpressure Re: Commercial Experiment Transporter planned (Forwarded) 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: 18 Jun 90 19:51:01 GMT From: swrinde!zaphod.mps.ohio-state.edu!rpi!uupsi!uhasun!lindh@ucsd.edu (Andrew Lindh) Subject: Re: Weather Satellite Photos In article <9006111133.AA15531@sky.compass.com>, wells@compass.com (Ian Wells) writes: > I would like to have daily pictures of the earth delivered on the > net. It would be great to have a picture of the hemisphere today > displayed on my screen. Henry says the images are easy to obtain. I am working on this NOW!!!! I hope to set up my network station this week (6/18/90) I have the PC and the WEFAX stuff will get here this week. The last part is to put up a good antenna. > I wonder how the images could be compressed enough to make it feasible > to blat them out over the net. Even uuencoded compress tar file I imagine > would be too large (final form would be postscript). Since a lot of the > image would be the same each day, could fractal algorithms be used > to compress the image further, given that each receiver had > a specialized program to uncompress the image. How small could the > transmitted image be made? > Ian Wells COMPASS,Inc wells@compass.com Yes the images are VERY large. Since we only have a 9600 baud line I don't know If I would allow too many people to get the images. It would be nice if someone with a T1 would store the images for FTP access. I would use compress...not uuencode. I would hope to produce GIF files. Postscript would NOT be a good choice...too big and too useless. Providing just the "changes" is a good idea....use whichever is smaller for that day. -- Andrew Lindh, a student at the University of Hartford -- Computer Science BITNET: LINDH@HARTFORD.bitnet INTERNET: lindh@uhasun.uofh.edu UUCP/Usenet: lindh@evecs.uucp ---- When will I grduate??? NOTE: All views here are MINE!!! Not the school's or those of anyone else! ------------------------------ Date: 18 Jun 90 20:54:27 GMT From: clyde.concordia.ca!mcgill-vision!quiche!calvin!msdos@uunet.uu.net (Mark SOKOLOWSKI) Subject: Re: US/Soviet Planetary Activity (was Re: Manned mission to Venus) In article <1755@nvuxr.UUCP> deej@nvuxr.UUCP (David Lewis) writes: >I've been watching this discussion, and I find the attitude that 'the >only worthwhile things to do are those which haven't been done' rather >distressing. If that were the common attitude, there would never be any >progress -- because nothing would ever get improved, refined, developed. >Do you want to be reading news on a 1950-era Univac by the light of an >Edison lightbulb? Not I, thanks. > We would still be in the trees if we would restrict ourselves to things that were done and are done on a regular basis. I think that's a truism that almost all of us share here. Mark S. ------- ------------------------------ Date: 18 Jun 90 20:21:41 GMT From: zaphod.mps.ohio-state.edu!samsung!rex!rouge!dlbres10@tut.cis.ohio-state.edu (Fraering Philip) Subject: Challenger accident (Was: Re: 10 psi overpressure) On a related topic, did the Challenger have a range safety package attached to it? Philip Fraering dlbres10@pc.usl.edu "Was that civilized? No. Even if it was fun." - _Gremlins 2: The New Batch_ ------------------------------ Date: Mon, 18 Jun 90 17:40:53 CDT From: John Nordlie Subject: Re: Model rocket contest I was did some reading and a few calculations concerning the specific impluse (Isp) of model rocket engines vs. conventional solid and liquid fueled rockets. Table 1 from "Introduction to Space Dynamics" by William Tyrell Thomson Chemical Propellants Type Specific Impulse, sec --------------------------------------------------------------------------- Ammonium nitrate rubber Solid 170 - 210 Potassium perchlorite thickol or asphalt Solid 170 - 210 Boron metal components and oxidant Solid 200 - 250 Liquid oxygen alcohol 250 - 270 Liquid oxygen flourine JP4 270 - 330 Flourine hydrogen 300 - 385 --------------------------------------------------------------------- Table 2 from "How to Design, Build, and Test Small Liquid-Fuel Rocket Engines" by Rocketlab, China Lake, Calif. Propellant Combination Oxidizer/Fuel Isp, sec ---------------------------------------------------- Liquid oxygen & gasoline 242 Gaseous oxygen & gasoline 279 Liquid oxygen & JP-4 (jet fuel) 255 Liquid oxygen & methyl alcohol 238 Gaseous oxygen & methyl alcohol 248 Liquid oxygen & hydrogen 363 Red fuming nitric acid & JP-4 238 ----------------------------------------------- Estes model rocket engine instructions have a table of engine thrust, total impulse, and propellant weight, as well as a graph of thrust versus burn time for all the model rocket engines they sell. I used the table to extrapolate burn times for 1 pound of propellant, then calculated the specific impulse (Isp) for the average model rocket motor from size "A" to size "D". Result : Isp = 81 on average for Estes model rocket engines. I calculated the Isp for a selected group of engines with the longest extrapolated burn times (about 63 seconds), and also for the average burn time (there were some 24 second and 45 second burn time figures), but the difference was only .37(Isp). What does this mean? A certin amount of energy is needed to lift a payload out of earth's gravity well. To supply this energy using model rocket engines with an Isp of 81, you would need 448% more propellant (by weight) than if you were using a oxygen/hydrogen fuel. I don't know the payload capacity of any small rockets that can achieve escape velocity, but I would guess that you would need an awful lot of model rocket engines (or one VERY big one) to equal the lifting power. Where did you get your figures for Isp, Vincint? I am curious. Also, where do you get "N" size model rocket engines? I have not been able to find a catalog that sells them. ==================================================================== John Nordlie : I STILL haven't thought of anything clever : to say, can you believe it? ==================================================================== ------------------------------ Date: 19 Jun 90 01:40:08 GMT From: portal!cup.portal.com!phorgan@apple.com (Patrick John Horgan) Subject: Re: Aim For The Moon - model rocket contest WOW! What an idea:) Is this really feasible? I would have thought that the normal construction methods for model rockets would result in the destruction of the model by the thrust of the early stages. Does anyone know the altitude record for model rockets using "normal", i.e. <= D size engines? Patrick Horgan phorgan@cup.portal.com ------------------------------ Date: 18 Jun 90 12:58:05 GMT From: trident.arc.nasa.gov!yee@ames.arc.nasa.gov (Peter E. Yee) Subject: CRRES mission briefing and spacecraft showing at KSC on June 22 (Forwarded) George H. Diller June 18, 1990 Kennedy Space Center 407/867-2468 KSC Release No. 105-90 NOTE TO EDITORS AND BROADCAST NEWS DIRECTORS: CRRES MISSION BRIEFING AND SPACECRAFT SHOWING AT KSC ON JUNE 22 The Combined Release and Radiation Effects Satellite (CRRES) to be launched aboard an Atlas Centaur rocket in mid-July will be the focus of a mission briefing and photo opportunity on Friday, June 22 at 11:00 a.m. CRRES will embark on a joint NASA/USAF mission to study the effects the radiation environment of space may have on advanced satellite electronics and sophisticated sensors. Chemical releases from the satellite in the ionosphere and magnetosphere will briefly "paint" the waves and lines of magnetic fields with luminous particles. Five chemical tracer elements to be expelled from 24 spacecraft canisters will create brilliantly visible releases in the Caribbean and South Pacific areas. Participating in the briefing will be: James L. Womack, Director of Expendable Vehicles NASA Kennedy Space Center William Swords, CRRES Project Manager NASA Marshall Space Flight Center Dr. David Reasoner, CRRES Project Scientist NASA Marshall Space Flight Center Colonel John E. Armstrong, Program Manager USAF Space Test and Transportation Program Office Major Stanley A. Sneegas, CRRES Program Manager USAF Space Systems Division The briefing will be on NASA Select television carried on Satcom F2R, transponder 13 located at 72 degrees W. Audio only is also available on the V-2 circuits which may be dialed directly at 407/867-1220....1240....1260. A two-way question and answer capability will be available at other NASA news facilities. At the conclusion of the briefing, news media will be taken by bus to the airlock of the Payload Hazardous Servicing Facility where preparations will be underway for encapsulating the CRRES spacecraft within the Atlas Centaur nose fairing. White room smocks and caps will be provided. Photographers may use electronic flash and battery powered lights. No outside power will be available. No shorts or skirts are permitted and flat, close-toe shoes are required. Camera accessories to be taken into the clean room must be transferred to special plastic bags which will be provided--no leather or vinyl can be taken into the facility. Quality control personnel may request a wipe- down of photographic support equipment such as tripods before entering the clean room area. The cleaning materials will be furnished. As propellant is aboard the spacecraft, no matches or lighters are allowed in the facility. Arrival back at the KSC News Center is expected at about 1:45 p.m. Media needing accreditation for this event should contact the NASA-KSC News Center at 407/867-2468 to request badging. The date of this event is driven by spacecraft readiness for encapsulation, so media representatives may wish to contact the news center a day in advance to assure there has been no change in the schedule. ------------------------------ Date: 15 Jun 90 21:17:40 GMT From: shelby!portia.stanford.edu!gooch@eos.arc.nasa.gov (Carl Gooch) Subject: Re: 10 psi overpressure In article <1990Jun12.182034.18698@csuchico.edu> rreid@cscihp.UUCP (Ralph Reid) writes: >In article <543.2673B35B@ofa123.fidonet.org> >David.Anderman@ofa123.fidonet.org (David Anderman) writes: >>I seem to recall that the Challenger was destroyed by air pressure, >>rather than an explosion of the external tank. Wouldn't that indicate >>the overpressure in the payload bay was somewhat higher than 10psi? >> . . . As I recall from a recent skim of the Rogers' Commission report, the leaking field joint in the SRB melted a hole in the hydrogen (lower) tank, while simultaneously melting the lower SRB attach point. The bottom of the hydrogen tank tore off completely shortly thereafter. The SRB then slewed into the oxygen (upper) tank, rupturing it on impact. The force of the explosion was, I'm pretty sure, what destroyed the Orbiter; it wasn't designed to take the stress of a detonation wave hitting its bottom surface. > >You seem to have forgotten the emphasis placed on redesigning the SRB >seals. I remember that pictures of the Challenger just prior to the >explosion were closely examined, and a blowtorch like flame was seen, >which extended from one of the SRB's to the external tank. Correct. The photos show that clearly. > Some one >told me (whether it is correct or not) that the main engines may have >been throttled up to 104% of capacity (this is a normal condition for >the main engines during launch) before the max-q point was reached. I don't know, but I doubt it. They throttle down to 65% for max-q, and I don't recall any mention to the contrary in the report. >If you have opinions, you can put them in your own article; >I refuse to put them in mine! These aren't opinions, although I may have my facts wrong. >Ralph. >ARS N6BNO >rreid@cscihp.csuchico.edu -- Carl Gooch gooch@portia.stanford.edu Disclaimer: You think Stanford actually agrees with this? Hah! If they want my opinions and theirs to match they should pay me enough to agree with them! ------------------------------ Date: 18 Jun 90 19:58:30 GMT From: zaphod.mps.ohio-state.edu!uakari.primate.wisc.edu!dali.cs.montana.edu!ogicse!unicorn!n8035388@tut.cis.ohio-state.edu (Worth Henry A) Subject: Re: Commercial Experiment Transporter planned (Forwarded) In message <51703@ames.arc.nasa.gov>, NASA announced: >RELEASE: 90-83 > >COMMERCIAL EXPERIMENT TRANSPORTER PLANNED > > > The National Aeronautics and Space Administration today >announced support for plans to develop a system for launching and >recovering commercial spaceborne experiments. > > Sponsored by NASA's Office of Commercial Programs, the >objective of the Commercial Experiment Transporter (COMET) >program is to develop both hardware and infrastructure to >facilitate the commercial development of space by the >United States. ... > First, a serious question ------------------------- Is this announcement an indication that NASA has seen the light and realized that the Space Station Freedom is doomed? Or, is it merely NASA's reluctant response to past congressional pressure to develop a commercial processing facility? Second, the commentary ---------------------- I hate to sound like a NASA basher -- I really want for them to prosper and succeed, I really do, I've been a big fan since I was a kid watching the later Mercury missions on the tube, and COMET does sound like a good idea -- It's just that I'm not willing to wait for ...er...ah...blush, Hades to freeze over. There must be another way to fund major space initiatives -- and for that matter, other important programs -- that does not depend upon continuous political support. I'm convinced that the solution is some form of voluntary funding and/or private incentive program, preferably international in scope and with potential tangible benefits for the contributors (I've already made one rather long posting on this subject a few days ago). If we wait for Washington to set the agenda and pace, little will ever come out of the NASA employees' years of work and frustration and the sacrifice of ten our finest (as well as four of the soviets'). Here're some fanciful thoughts to help stimulate the net's collective grey matter: To augment its budget, authorize NASA to run a nation-wide lottery and a major Cape Canaveral casino and theme park, and perhaps at Edwards as well -- of course, keeping the bureaucrats' and politicians' hands off the earnings is a major problem, not to mention the ethical problem of taking advantage of habitual gamblers -- ...oh well, better NASA than Trump and Eisner. :-) NASA is not going to benefit from the mythical peace dividend -- the big hogs have already crowded the NASA runt from the trough, but don't fret... they are ALL going to go hungry -- the S&L rats have already emptied the slop bucket. The remaining concern is how long does the runt have before Farmer Sam decides to do the humane thing... :-( :-( :-( It's really a shame that NASA's supporters didn't get into the S&L business a decade ago -- they wouldn't have to be at all concerned about today's S&L bailout -- they would have been protected by a non-extradition clause in the Martian Constitution. :-) :-) :-( I don't remember where I first heard this approach, but schemes like the following have been used before in the private sector: It's time to make it more profitable to quit a useless civil- service job than to stay and milk the taxpayers. Any civil-servant who demonstrates that their job is superfluous would be awarded a long-term full-salary severance, even if they find another job within the government (after all, we would hardly want to lose such a conscientious civil servant, who might eliminate yet another job ). Similarly, civil-servants would also receive substantial awards for being the first to demonstrate that an vacant position is superfluous. The recipient would also be allowed to assign a limited portion of their award to a third party who has aided them in demonstrating their own job's uselessness, thus creating a temporary new industry for departing civil-servants and under-employed lawyers, and a new definition for "head-hunter". The claims would be reviewed by inter-agency committees selected at random from existing employees, both management and peer, who would serve on a temporary basis. Such a plan would cost the government nothing, and yet would create larger dividends for the taxpayer (and possibly NASA) than any potential peace dividend. Perhaps, if Congress in its usual short- sightedness refused to approve significant awards, the private sector would be willing to create an award fund. Note, that under this plan you can eliminate only your own job or one that is vacant -- otherwise some nasty and unproductive infighting would result. If NASA's employees were to spearhead such a program, they would generate significant goodwill on Capital Hill as well with the general public. :-) ------------------ 06/17/90 --------------------- ------------------------------ End of SPACE Digest V11 #539 *******************