Date: Sat, 8 Aug 92 05:04:58 From: Space Digest maintainer Reply-To: Space-request@isu.isunet.edu Subject: Space Digest V15 #086 To: Space Digest Readers Precedence: bulk Space Digest Sat, 8 Aug 92 Volume 15 : Issue 086 Today's Topics: Circles on map Galileo Update - 08/07/92 Giotto - First Results from Comet Encounter Hubble used for spying? mathematical models ReEe: aA 12 mile tether that gernerates 5000v? Source of moon/apollo pix TSS Two-Line Orbital Element Set: Space Shuttle Welcome to the Space Digest!! Please send your messages to "space@isu.isunet.edu", and (un)subscription requests of the form "Subscribe Space " to one of these addresses: listserv@uga (BITNET), rice::boyle (SPAN/NSInet), utadnx::utspan::rice::boyle (THENET), or space-REQUEST@isu.isunet.edu (Internet). ---------------------------------------------------------------------- Date: 8 Aug 92 04:59:50 GMT From: John Roberts Subject: Circles on map Newsgroups: sci.space -From: henry@zoo.toronto.edu (Henry Spencer) -Subject: Re: Weird circle-like things on shuttle map -Date: 7 Aug 92 20:36:47 GMT -Organization: U of Toronto Zoology ->On the NASA channel, when they display the globe with the ->shuttle moving around, there are all these cirlce-like things ->that have strange grooves. -Those are the areas where a shuttle at orbital altitude is in line-of-sight -(for radio transmissions) of a ground station in the center of the circle. -There are bites out of some of them because of things like mountains that -block the view in some directions for some stations. There's also a circle of the same size showing the Earth's horizon as seen from the orbiter. The size of the circle is a function of the altitude of the Shuttle. Note that only a tiny fraction of the Earth's surface can be seen from the orbiter at any given time. In low Earth orbit, nearly half of the field of view is taken up by the Earth. John Roberts roberts@cmr.ncsl.nist.gov ------------------------------ Date: 8 Aug 92 07:40:25 GMT From: Ron Baalke Subject: Galileo Update - 08/07/92 Newsgroups: sci.space,sci.astro Forwarded from Neal Ausman, Galileo Mission Director GALILEO MISSION DIRECTOR STATUS REPORT POST-LAUNCH July 30 - August 6, 1992 SPACECRAFT 1. Commands were sent on July 31 to increase the spacecraft power margin to warm the RPM (Retro_Propulsion Module) propellant tanks in preparation for TCM-14 (Trajectory Correction Maneuver #14) on August 4-7. 2. Cruise Science Memory Readouts (MROs) were performed by the stored sequence for the MAG (Magnetometer) and DDS (Dust Detector) instruments on August 2 and for the EUV (Extreme Ultraviolet Spectrometer) instrument on August 3. An additional real-time EUV MRO was performed on July 31, to return recent data for comparison with earlier EUV data taken under similar solar conditions. 3. Another RPM 10-Newton thruster maintenance activity was performed on August 3. The activity "flushed" all 12 thrusters; spacecraft performance throughout the activity was normal. 4. In preparation for the start of the TCM-14 maneuver, the spacecraft performed a 4-degree SITURN on August 4 to the desired maneuver attitude. 5. TCM-14 maneuver sequence memory loads were sent to the spacecraft for maneuver potions A, B, and C on August 4, 5, and 6, respectively. Each maneuver portion, using the L-thrusters is designed to impart a delta velocity of 6.2 m/sec. The last maneuver portion (D) is scheduled to be sent on August 6 for execution on August 7 and will use the L-thrusters and the axial (Z) thrusters to achieve a delta velocity of about 2.3 m/sec. Total delta velocity from the TCM is expected to be about 21 m/sec. 6. The first three portions of TCM-14 consisted entirely of lateral burns with each portion containing six nearly identical burn segments. The spacecraft performance throughout the maneuver activity was normal and near expected levels. In particular, the RPM tank pressures and temperatures were normal throughout the 18 burn segments. After the second segment a portion A, a sequence planned spin correction and pointing correction activity was performed. This correction reduced an accumulated 20 mrad pointing error to about 4 mrad. Similarly, other sequence planned pointing corrections were performed after burn segments 4 and 6. Preliminary radio navigation data for TCM-14A indicates about a two percent overburn. TCM-14B and TCM-14C portion were performed on August 5 and 6, respectively. These maneuver portions, like TCM-14A, exhibited somewhat larger than expected accumulated pointing error. Furthermore, it was observed that the accumulated pointing error gradually decreased after each burn segment. The cause for this unexpected pointing error behavior is unclear but it may suggest that one L-thruster is performing about one to two percent above predict. Radio navigation data after TCM-14B and TCM-14C indicates about a 1.6 and 1.1 percent overburn, respectively. The integrated 3-portion overburn is about 1.4 percent. The final portion, TCM-14D, will be performed on August 7. This last portion consists of one small (0.4m/sec) axial burn followed by a three segment lateral burn of 2.3m/sec. 7. The AC/DC bus imbalance measurements exhibited little change. The AC measurement toggled 1 DN and reads 3.1 volts. The DC measurement increased 6 DN for a short time and then returned close to its previous value and now reads 14.7 volts. Intermittently during pre-TCM burn segments, the DC imbalance changed and then returned to its previous value. There was no consistency as to when changes occurred, i.e., during burns or pre/post burns. This measurement variation is consistent with the model developed by the AC/DC special anomaly team. 8. The Spacecraft status as of August 6, 1992, is as follows: a) System Power Margin - 70 watts b) Spin Configuration - Dual-Spin c) Spin Rate/Sensor - 3.16 rpm/Star Scanner d) Spacecraft Attitude is approximately 3.1 degrees off-sun (lagging) e) Downlink telemetry rate/antenna-40 bps (coded)/LGA-1 f) General Thermal Control - all temperatures within acceptable range g) RPM Tank Pressures - all within acceptable range h) Orbiter Science- UVS, EUV, DDS, MAG, EPD, and HIC are powered on i) Probe/RRH - powered off, temperatures within acceptable range j) CMD Loss Timer Setting - 264 hours Time To Initiation - 264 hours UPLINK GENERATION/COMMAND REVIEW AND APPROVAL: 1. The TCM-14 final sequence and command product was approved by the Project on July 31. The maneuver is scheduled to be performed from August 4 thru August 7. TRAJECTORY As of noon Thursday, August 6, 1992, the Galileo Spacecraft trajectory status was as follows: Distance from Earth 106,822,460 miles (1.16 AU) Distance from Sun 160,260,630 miles (1.73 AU) Heliocentric Speed 48,550 miles per hour Distance from Jupiter 664,407,490 miles Round Trip Light Time 19 minutes, 16 seconds SPECIAL TOPIC 1. As of August 6, 1992, a total of 8108 real-time commands have been transmitted to Galileo since Launch. Of these, 3230 were pre-planned in the sequence design and 4878 were not. In the past week, 14 real time commands were transmitted; 8 were pre-planned in the sequence design. In addition, 5427 mini-sequence commands have been transmitted since March 1991; 3269 were pre-planned and 2158 were not. In the past week, 44 mini-sequence commands (SITURN) were transmitted. Major command activities this week included SITURN, EUV MRO, and power reconfiguration activities. 2. The unexpected lock changes observed during the DSS-63 (Madrid 70 meter antenna) pass are believed similar to the many others observed during the past two years. The tracking conditions for this recent event appears similar to some of those observed on previous occurrences. There was no evidence that the spacecraft received or issued a command during the unexpected lock change. This recent lock change information was passed to the team working the lock change ISAs. ___ _____ ___ /_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov | | | | __ \ /| | | | Jet Propulsion Lab | ___| | | | |__) |/ | | |__ M/S 525-3684 Telos | You can't hide broccoli in /___| | | | ___/ | |/__ /| Pasadena, CA 91109 | a glass of milk - |_____|/ |_|/ |_____|/ | anonymous 7-year old. ------------------------------ Date: 8 Aug 92 07:48:30 GMT From: Ron Baalke Subject: Giotto - First Results from Comet Encounter Newsgroups: sci.space In article <504@alden.UUCP>, sgr@alden.UUCP (Stan Ryckman) writes... >In article <1992Aug5.211812.20796@elroy.jpl.nasa.gov> baalke@kelvin.jpl.nasa.gov writes: >>ESA News Release > >> At 15:30:56 the Dust Impact Detectors reported the first impact of >>a fairly large particle, followed by two smaller ones. > >What is the range of "fairly large?" I've heard the particle was estimated to be about 30 milligrams, and may be larger than any of the particles encountered at Halley. ___ _____ ___ /_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov | | | | __ \ /| | | | Jet Propulsion Lab | ___| | | | |__) |/ | | |__ M/S 525-3684 Telos | You can't hide broccoli in /___| | | | ___/ | |/__ /| Pasadena, CA 91109 | a glass of milk - |_____|/ |_|/ |_____|/ | anonymous 7-year old. ------------------------------ Date: 5 Aug 92 00:56:16 GMT From: "Hoyt A. Stearns jr." Subject: Hubble used for spying? Newsgroups: sci.space In article <1992Aug3.170409.22112@aio.jsc.nasa.gov> kjenks@gothamcity.jsc.nasa.gov writes: >No. The Earth is too bright, even at night. Pointing Hubble at Earth >(or even the moon) would burn out (or seriously endanger) the Faint >Object Camera. > A PBS broadcast on spying a couple of years ago described the KH11 and KH12 spy satellites. They seemed remarkably similar in size and shape to the Hubble telescope. Are you sure they're not related? :-) -- Hoyt A. Stearns jr.|hoyt@ | International Society of Unified Science| 4131 E. Cannon Dr. |isus.tnet.com | Advancing Dewey B. Larson's Reciprocal | Phoenix, AZ. 85028 |ncar!enuucp! | System- a unified physical theory. | voice_602_996_1717 telesys!isus!hoyt The Universe in two postulates!_________| ------------------------------ Date: 8 Aug 92 02:54:58 GMT From: John Roberts Subject: mathematical models Newsgroups: sci.space -From: kym@bingsuns.cc.binghamton.edu (R. Kym Horsell) -Subject: Re: Origin of Life article -Date: 7 Aug 92 22:43:23 GMT -Organization: State University of New York at Binghamton -In article <9208072003.AA27061@cmr.ncsl.nist.gov> roberts@CMR.NCSL.NIST.GOV (John Roberts) writes: ->There are mathematical formulas for the evaluation of the probability of ->a hypothesis being correct given a particular number of observations. ->Putting biogenesis into mathematical terms may be of limited usefulness ->at this point, because we know so little about it. -This is rather misleading. The area alluded to is called induction. -To consider the difficulty of comming up with such formulae -- consider -the following. An event happens ``n'' times in a row. What is the -prob of it happening the ``next time''. You may say: n/n=1 (i.e. -it is certain to happen). You may say 1/2 (i.e. 50:50) or you -may say 1/(n+1). This last formula is meant to be a compromise -(we have learnt _something_ from the string of n events; but -there is still some uncertainty). -All formulae above can be used (so far as I know) interchangabley; -none leads to a contradiction. (Unless you set up your system of -math logic to, e.g., specifically preclude it :). -There are thus no ``mathematical formulas for evaluation of -the probability of a hypothesis''. Various statisticians will -give me an argument. But they are wrong. :) Predicting a future event is different from evaluating the degree of confidence that a given distribution model is correct. I don't know about you, but if I had a coin that came up heads a million times in a row, I'd be pretty dubious about the model that it's a fair coin. :-) There are tests like chi-squared for conformance of a statistical sample to an expected distribution. I don't know if this is what's used for Boolean random variables, or if something else is used. Is there a mathematician in the house? Also see "Rosencrantz and Guildenstern are Dead" by Somebodyorother (sort of a takeoff on Shakespearean plays). John Roberts roberts@cmr.ncsl.nist.gov ------------------------------ Date: Thu, 6 Aug 1992 20:32:01 +0000 From: Andrew Haveland-Robinson Subject: ReEe: aA 12 mile tether that gernerates 5000v? Newsgroups: sci.space In article <1992Aug4.100338.1502@uni2a.unige.ch> pfennige@uni2a.unige.ch writes: >In article <712744069snx@osea.demon.co.uk>, andy@osea.demon.co.uk (Andrew> Haveland-Robinson) writes: >> >> In article <1992Jul31.054058.15957@mnemosyne.cs.du.edu>> rkornilo@nyx.cs.du.edu writes: >> >>>The 5000 volts are induced by the Earth's magnetic field as the spacecraft >>>orbits. The same principle in using magnets to enduce a voltage when you >>>pass a magnet through a coil of wire. >> >> I can see that this will work, though it's practicality may be limited >> as it would start to slow down the shuttle if any serious power could >> be drawn. >> >On the contrary, if energy is extracted from an orbiting body, its kinetic >energy *increases* by this exact amount. All this additional energy is >provided by the gravitational binding energy. A very useful use of a tethered >loop could be not to extract electric energy at the expense of gravitational >energy, but the contrary: electric energy, coming from solar cells for >instance, can then be used in the opposite way to lift up the satellite orbit. > > Daniel Pfenniger You make some interesting though to my mind, rather curious assertions. How does it gain kinetic energy if you take energy out of it? I think I need some clarification of the principles at work here... As I understand it, if you take energy out of an orbiting body, it moves into a higher orbit at a slower velocity. If you take more out then it ceases to orbit and starts falling to earth. If there is still an angular moment then it will stabilise in an orbit (if the Earth doesn't get in the way of the trajectory!). I have a problem in conceptualising how to get an object to orbit lower and quicker. If you speed it up wouldn't also tend to find a higher orbit and slow down? I suppose the current will alternate during the orbit too, depending on which orbit was chosen (I guess a polar one would be most productive). Confused of Osea +-------------------------------------------------------------------------+ | Haveland-Robinson Associates | Email: andy@osea.demon.co.uk | | Pine Cottage, Osea Island, Essex | ahaveland@cix.compulink.co.uk | | CM9 8UH England. 0621-88756 | Also: 081-800 1708 081-802 4502 | +-------------------------------------------------------------------------+ ------------------------------ Date: Sat, 8 Aug 1992 06:21:00 GMT From: seds%cspara.decnet@Fedex.Msfc.Nasa.Gov Subject: Source of moon/apollo pix Newsgroups: sci.space In article <1992Aug7.222234.4379@aio.jsc.nasa.gov>, hack@arabia.uucp (Edmund Hack) writes... >In article <1992Aug7.135632.1@fnalf.fnal.gov> higgins@fnalf.fnal.gov (Bill Higgins-- Beam Jockey) writes: >>I suspect the Moon just is *not* available in digital form.... though >>Dennis Wingo has talked about digitizing some of the Lunar Orbiter >>microfiche just for fun. The USGS people in Flagstaff would know more >>than anybody about the availability of Moon data. > >According to my contacts at JSC and LPI, none of the Lunar Orbiter or >Apollo CSM photography is in useable digital form. All that exists for >Apollo are long rolls of B&W prints (and the negatives) and maps made by >USGS and DMA from the stereo pairs. A project I am working on part-time >may turn some of the photography and cartography data from the landing >sites into digital terrain maps. > >Due to the early date of the lunar spacecraft designs, the maps we have >of Mars are more comprehensive and accurate than those of the moon. > > >-- >| Edmund Hack - Lockheed Engineering & Sciences Co. - Houston, TX >| hack@aio.jsc.nasa.gov SpokesPersonp(Me,or(NASA,LESC)) = NIL >| "No the game never ends when your whole >| world depends on the turn of a friendly card" If anyone wants to come and spend a couple of weeks here in Huntsville and do the work, we can digitize the Lunar orbiter images. We have some reall spiffy cameras and scanners to scan the Micrfilm images from LO I-V. I just do not have the time to do it now, I apologize. I do have a few spiffy images from LO IV that I gave to you on floppy Bill Higgins in 1989. You still have them? They showed some really great lava tubes and we did a little playing around with them back then but I am building a satellite and numerous shuttle payloads now and just can't do it. There is some really good stuff here and I hope that someone will take us up on this. We can put it on a R/W optical disk and then Transfer them to CD ROM for distribution. Is there any interest in this? Please mail me at the above address. Thanks to John Roberts we now can correlate the images that I have with their approximate locations. I was able to figure that out finally John. Dennis, University of Alabama in Huntsville. ------------------------------ Date: 8 Aug 92 04:50:36 GMT From: John Roberts Subject: TSS Newsgroups: sci.space -From: cshotton@oac.hsc.uth.tmc.edu (Chuck Shotton) -Subject: Re: More second-hand info on TSS -Date: 5 Aug 92 18:51:02 GMT -Running 12 miles of cable off a spool doesn't seem to be a particularly -difficult task, even in zero G. Why is it that we have another -over-engineered solution that has apparently failed? Is this really any -more difficult to engineer that an elaborate fishing reel? I'm sure it's a -LOT simpler than most other shuttle systems (including the toilet!). -It's a little discouraging to continually see minor things screwing up -over-hyped shuttle missions (like non-functional grapple bars, jammed fax -machines, burned out cooling fans, Notice a recurring theme? Tried and true on Earth, then problems show up in space. Maybe it's just that it's harder to do things in space conditions, and it's hard to simulate space conditions on Earth. Of course, being aware of this problem, it's a good idea to plan for numerous tests. For instance, they could run a smaller tether experiment on many missions, as time allows. untested telescope mirrors, etc.) That's not quite correct for HST. The primary mirror was extensively tested, and in fact the tests showed the error. Hughes Danbury decided to ignore the warning signs, and not to inform NASA. -I'm not flaming anyone. I seriously want to know how this cable mechanism -was designed and tested and how such a simple mechanism can be so screwed -up. It was tested on Earth, and showed no problems. I think they should have designed it for constant tension on the reel. Maybe they will, next time. :-) John Roberts roberts@cmr.ncsl.nist.gov ------------------------------ Date: 8 Aug 92 04:05:41 GMT From: TS Kelso Subject: Two-Line Orbital Element Set: Space Shuttle Newsgroups: sci.space The most current orbital elements from the NORAD two-line element sets are carried on the Celestial BBS, (513) 427-0674, and are updated daily (when possible). Documentation and tracking software are also available on this system. As a service to the satellite user community, the most current elements for the current shuttle mission are provided below. The Celestial BBS may be accessed 24 hours/day at 300, 1200, 2400, 4800, or 9600 bps using 8 data bits, 1 stop bit, no parity. Element sets (also updated daily), shuttle elements, and some documentation and software are also available via anonymous ftp from archive.afit.af.mil (129.92.1.66) in the directory pub/space. STS 46 1 22064U 92 49 A 92219.67708333 .00381304 69070-4 25599-3 0 201 2 22064 28.4752 306.2844 0005231 278.3917 146.5572 16.15583754 969 EURECA 1 22065U 92 49 B 92219.56250000 .00000116 00000-0 99999-7 0 160 2 22065 28.4567 308.9498 0027753 318.6810 283.7589 15.26603958 918 -- Dr TS Kelso Assistant Professor of Space Operations tkelso@afit.af.mil Air Force Institute of Technology ------------------------------ End of Space Digest Volume 15 : Issue 086 ------------------------------