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, 20 Jun 1990 01:45:55 -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, 20 Jun 1990 01:45:23 -0400 (EDT) Subject: SPACE Digest V11 #543 SPACE Digest Volume 11 : Issue 543 Today's Topics: NASA Headline News for 06/18/90 (Forwarded) Re: Aim For The Moon - model rocket contest Re: Model rocket contest Hubble Space Telescope Update - 06/16/90 Compression of similar images: WAS:WeatherSatellitePhotos 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: 19 Jun 90 18:20:28 GMT From: trident.arc.nasa.gov!yee@ames.arc.nasa.gov (Peter E. Yee) Subject: NASA Headline News for 06/18/90 (Forwarded) ----------------------------------------------------------------- Monday, June 18, 1990 Audio Service: 202/755-1788 ----------------------------------------------------------------- This is NASA Headline News for Monday, June 18....... The orbiter Atlantis successfully completed the Shuttle Interface Test this weekend. It rolled out to Launch Pad 39-A late last night. Before the Rotating Service Structure is placed around the Space Shuttle, a hot-firing test of the Auxiliary Power Units will take place tonight at 10:00 P.M. The STS-38 flight crew will arrive at 8:30 P.M. to prepare for the Countdown Demonstration Test and emergency safety training scheduled for Wednesday and Thursday, June 20-21. ******** The Combined Release and Radiation Effects Satellite to be launched aboard an Atlas Centaur rocket in mid-July will be the focus of a mission briefing on Friday, June 22 at 11:00 A.M. The mission will study what the effects the radiation environment of space may have on satellite electronics and sensors. Chemical releases from the satellite in the ionosphere and magnetosphere will briefly "paint" the waves and lines of magnetic fields with luminous particles. Tracer elements expelled from the spacecraft canisters will create visible releases in the Caribbean and South Pacific Areas. ******** NASA plans to support efforts to develop a system for launching and recovering commercial spaceborne experiments. The Commercial Experiment Transporter Program will develop both the hardware and infrastructure to facilitate the commercial development of space in the U.S. The COMET Program calls for a mid-1992 launch of a free-flyer that contains both a service module and a recovery system into equatorial orbit. It weighs 1,800 pounds and the experiments onboard the spacecraft can be carried out during a nominal 30-day mission. ******** Pennsylvania State University researchers plan to study how to keep muscles and bones healthy in space. Dr. Peter Cavanagh will head a 3-year NASA study to examine how impact forces can be applied to astronauts' feet and legs during prolonged space flight in order to counteract hypokinetic osteoporosis. A weightlessness simulator will suspend a subject on a "wall-tread mill" supported by a system of elastic bunjy-like cords with force-measuring devices. Researchers expect it to be up and running this August. ******** -------------------------------------------------------------- Here's the broadcast schedule for Public Affairs events on NASA Select TV. All times are Eastern. Tuesday, June 19........ 12:00-2:00 P.M. NASA Video Productions Wednesday, June 20...... 2:00-4:00 P.M. Tape of President Bush arrival at Marshall Space Flight Center. 4:00 P.M. X-29 Press Conference taped at 12:45 P.M. at Watergate. Thursday, June 21 10:00 A.M. STS-38 countdown demonstration test. Liftoff will be at 11:00 A.M. 11:30 A.M. NASA Update will be transmitted. Friday, June 22......... 11:00 A.M. CRRES mission briefing and photo opportunity. For more information call 407/867-2468. ----------------------------------------------------------------- All events and times are subject to change without notice. These reports are filed daily, Monday through Friday, at 12:00 P.M. EDT. This is a service of the Internal Communications Branch, NASA HQ. Contact: JSTANHOPE or CREDMOND on NASAmail or at 202/453-8425. ----------------------------------------------------------------- NASA Select TV: Satcom F2R, Transponder 13, C-Band 72 Degrees West Longitude, Audio 6.8, Frequency 3960 MHz. ----------------------------------------------------------------- ------------------------------ Date: 20 Jun 90 02:55:49 GMT From: sam.cs.cmu.edu!vac@pt.cs.cmu.edu (Vincent Cate) Subject: Re: Aim For The Moon - model rocket contest Patrick John Horgan >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. Feasible really boils down to, "How much money can you spend?". If you have $30,000 I am rather sure it is feasible. If you have $5,000, I think it is. If you have $2,000, maybe. A big part of the contest would be designing for low cost. I don't think the high Gs would be all that much more than model rockets are used to. There is no real reason that the acceleration from the lower stages would be any higher than the upper stages. If each stage is half the size of the previous one (with the payload equal to the weight of the last stage), each motor is pushing on upper stages about equal to its starting weight (modulo cases). Thus each stage could add about the same delta-V with about the same acceleration. From: cobbhs@AFSC-SDX.AF.MIL ("1st Lt. Henry S. Cobb") >Five years ago, the MIT ... > >The goal was to put 1 kilogram in orbit. We learned a lot, especially that >things like guidance systems do not shrink nearly as easily as fuel tanks. > >The SCOUT Planning Guide says that a Scout booster (21500 kg GLOW) can put >a 250 kg payload into a 200 Km orbit, which is about as low as you can get >and still call it an orbit. Linear scaling says that an 86 kg model rocket >could put 1 kg into the same orbit. Unfortunately, the scaling ain't >linear! If we only put 1 oz or 100 grams into space it would still be loads of fun. Only :-) control, the motor cases, and air resistance are not linear. If large rockets cost about $10,000/lb to send stuff into GEO then getting 1 oz near the moon for $5,000 still leaves a factor of 8 for non-linear scaling. You just aren't thinking small enough!!!! >Scout is about as simple a rocket as you can get. The stages are all solid >fuel, more or less the same as high-class model rocket engines. The >guidance system is incredibly simple: a roll-yaw stabilization gyro, a >pitch stabilization gyro, and a timer. The timer kicks the pitch gyro >occasionally to bend the trajectory downrange. Even though it's 1960 >technology, you're not going to build a system much lighter than that >with microprocessors. The fourth (and optional fifth) stages are spun up >pointing in the right direction, but otherwise unguided. What if we just use fins on the first stage or two to get going and spin things up, and then just use the spin for all of the later stages? No control computer or servos at all!!!! If we can keep within 15 degrees of vertical we should be just fine, assuming the goal is just to get up. It would be just about as fun to fly past the moon 100,000 miles away as it would be to hit the moon. Also, remember that the moon will pull things towards it. Getting into orbit would need active control and so ruin the scaling. You would need lots of servos and a computer. I don't think you need this just to "Aim For The Moon". -- Vince ------------------------------ Date: 19 Jun 90 11:48:28 GMT From: netnews.upenn.edu!grad2.cis.upenn.edu!santerel@rutgers.edu (Walter Santarelli) Subject: Re: Model rocket contest In article UD186413@VM1.NODAK.EDU (John Nordlie) writes: > [reference deleted referring to model rocket contest idea] > >This sounds like a very neat idea, if it can be done. However, I have >some difficulty believing that a gun powder (model rocket engine >propellant is basically gun powder, with some other burn-controlling >chemicals added) rocket could achieve escape velocity, starting from >the earth's surface. I remember reading in a book on rockets and >jets that a gun powder powered rocket the size of a Saturn V cound >not reach escape velocity. The chemical potential energy per unit >weight is simply not high enough. > >I have never heard of an "N" model rocket engine ("A" - "F" yes, >but not "N"), so I may be wrong about the fuel used in them. If these >"N" engines were to use a suitably volatile solid fuel, it MIGHT >be possible to get one into LEO, or better. > There are larger engines than "F". Many of the "E" and higher total impulse engines use a perchlorate fuel which supplies a pretty high specific impulse. These engines are not manufactured by Estes and can usually only be obtained through mail-order. However, despite the higher energy capacity of these larger engines, there is significant amount of packaging material mass around the fuel. When I was in high-school some people at MIT did some calculations about getting into LEO using "F"'s and found that the packaging mass defeats the gains obtained from increased numbers of engines in series or parallel. This may not apply to the larger "G" and "H" engines which are available. I am not aware of any place that will sell "N" size engines to someone without special licensing. These are in the "Amateur" rocket range. Amateur rocketeers launch what can be described as small sounding rockets, and they don't even get into orbit. They do get sub-orbital flights with altitudes of 20-30 miles. Even LEO requires a heck-uv-alot of energy. > >------------------------------------------------------------------------ >John Nordlie : (Sorry, I couldn't come up with any clever > : message/quote/disclaimer today) >------------------------------------------------------------------------ -wally ------------------------------------------------------------------------------ Walter A. Santarelli University of Pennsylvania, Computer and Info. Science (Grad Student) "My opinions are my own etc." e-mail:santerel@grad1.cis.upenn.edu (the only address I know that works) ------------------------------------------------------------------------------ ------------------------------ Date: 19 Jun 90 15:34:33 GMT From: usc!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov!baalke@ucsd.edu (Ron Baalke) Subject: Hubble Space Telescope Update - 06/16/90 Hubble Space Telescope June 16, 1990 First analyses of the Planetary Camera (PC) images are in, essentially they confirm the first visual impressions of the data. A significant change in the image quality did occur after the focus movement on June 14: encircled energy plots show that the core of the images narrowed and there was an expansion of the faint halo. Both the images and the encircled energy plots show clear improvement. The images taken after the tilt and decentering movement of the secondary show essentially no significant difference between the before and after images. Why there was no change is still not understood. Resolution of the puzzle must await further wavefront measurements, now scheduled for June 18. Scientific Instrument (SI) activities have gone extremely well: Faint Object Spectrograph (FOS) recovered from safemode and all Goddard High Resolution Spectrograph (GHRS) testing has gone extraordinarily well. Faint Object Camera (FOC) first light is still scheduled to begin early on June 17, with the first of the 10 images to be taken at 3:40 AM EDT. Tape recorder dumps will be scattered throughout the FOC run. Nothing new on any of the Pointing Control Subsystem (PCS) problems. The mirror movements on June 15 required a new alignment matrix to be constructed since it changed the relationship between the Fixed Head Star Tracker (FHST) and Optical Telescope Assembly (OTA) optical axes. This was successfully done and the changes were what was anticipated. FHST updates have been working very well but this should not be taken as proof that the FHST problems are solved. It has been pointed out that virtually all of the updates have been at the same few attitudes, attitudes that have been very thoroughly checked out by the Astrometry team. A better assessment of how the FHST's are doing can be done once the spacecraft is moved to new attitudes. Analysis of the past few days mirror movement was given above. The image quality was significantly improved by the focus movement but uneffected by the subsequent tilt and decentering. It is known that this latter movement actually did occur because of the change in the FHST/FGS (Fine Guidance Sensor) alignment matrices. Why it had essentially no impact on the image is under study. No mirror movements will be made between now and the FOC first pictures. On June 18 more wavefront measurements will be made to check out the optics in a more rigorous way. All next week (Monday through Sunday) Bootstrap focus and alignment proposals will be only HST activity. FOC is still in hold on the B side awaiting FOC first light. The FOC first light will be 10 images obtained with the F/96 side of a field in NGC 188 containing two astrometric standards. Each exposure is 10 minutes in length (through 6 magnitudes of ND filters). The purpose of the images is to locate and map the 22 arcsec Field of View (FOV). FOS is in hold, having successfully recovered from safemode. Nothing is planned for the FOS for the next few days. GHRS has had a very active and successful weekend. Activity on June 15 was all done on Side 1, Side 2 testing starts on June 16. Detailed analysis of the data is in progress. Preliminary comments: High Voltage (HV) on went very well, the focus was found to be identical to that found in thermal vacuum tests, pulse height results look fine, and all apertures were seen during the bright earth observation. If the next set of GHRS tests go well this will complete their OV 1 activities. The Wide Field Planetary Camera (WFPC) is in full operate mode. No more PC pictures are scheduled until next week. _ _____ _ | | | __ \ | | Ron Baalke | baalke@mars.jpl.nasa.gov | | | |__) | | | Jet Propulsion Lab | baalke@jems.jpl.nasa.gov ___| | | ___/ | |___ M/S 301-355 | |_____/ |_| |_____| Pasadena, CA 91109 | ------------------------------ Date: 19 Jun 90 21:41:29 GMT From: usc!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!watserv1!maytag!watdragon!rose!sekoppenhoef@ucsd.edu (Shawn E. Koppenhoefer) Subject: Compression of similar images: WAS:WeatherSatellitePhotos >> 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 What if a particular image was used (call it IM_0) and then successive images (IM_1 IM_2 ... IM_n) then compared with IM_0 and only the differences saved and transmitted across the net. When the image becomes too different a new 'parent' is created ( IM_0' ) and the process repeats. So each image-file IM_t would have a special header identifying it as a unique parent (parent0000) or as a child of a particular parent (child_of_0000). Comments? -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~| _ _ KLEIN BOTTLE for sale... Shawn E. Koppenhoefer | | enquire within. ...watmath!rose!sekoppenhoef | - ~~~~~~~~~~~~~~~~~sekoppenhoef@rose.uwaterloo.ca sekoppenhoef@rose.uwaterloo.edu ------------------------------ End of SPACE Digest V11 #543 *******************