Return-path: X-Andrew-Authenticated-as: 7997;andrew.cmu.edu;Ted Anderson Received: from po9.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 ; Fri, 19 Oct 90 02:59:25 -0400 (EDT) Received: from beak.andrew.cmu.edu via qmail ID ; Fri, 19 Oct 90 02:57:51 -0400 (EDT) Message-ID: Precedence: junk Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Fri, 19 Oct 1990 02:56:23 -0400 (EDT) Subject: SPACE Digest V12 #467 SPACE Digest Volume 12 : Issue 467 Today's Topics: Magellan Update - 10/17/90 Re: Venus/Magellan, poles More on OSC and Pegasus Re: Man-rated SRBs Re: Pioneer 11 Update - 10/17/90 Re: planetary north and names Re: Reflexes (teleoperators) Re: Ulysses Update - 10/16/90 Pioneer 11 Update - 10/16/90 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: 17 Oct 90 22:03:26 GMT From: julius.cs.uiuc.edu!wuarchive!sdd.hp.com!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov!baalke@apple.com (Ron Baalke) Subject: Magellan Update - 10/17/90 Magellan Status Report October 17, 1990 All spacecraft systems are performing nominally as Magellan completes its 236th orbit. The 7 star calibrations and 2 desaturations of the past 24 hours were fully successful with nominal attitude updates. On two recent mapping passes, the two gyroscopes measuring the spacecraft motion in the X axis gave differing values. These miscompares were very small (0.02 radians), but are possibly related to the solar array drive problem since its position errors are also in the X axis. The cause is being investigated. The upload yesterday, to fill parts of AACS (Attitude and Articulation Control Subsystem) Memory B with alternating 1's and 0's, inadvertently overwrote a buffer area which was not supposed to be filled. This was corrected by uplinking a small memory patch. The mapping sequence load and radar parameter files were uplinked without problems. The radar system continues to operate normally, but there has been a significant increase in the telemetry channel bit errors. When the data is lost, the computer fills the data record with zeros. On orbit #598, for example, about one-fourth of the record was zero-filled. This degradation of the SAR (Synthetic Aperture Radar) data was expected as Magellan approaches Superior Conjunction. Fourteen new standard image swaths were produced by the SAR Processor yesterday. Five mosaicked images are being produced in the Image Data Processing System to assess the radar system performance. ___ _____ ___ /_ /| /____/ \ /_ /| | | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov ___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov /___| | | | ___/ | |/__ /| M/S 301-355 | |_____|/ |_|/ |_____|/ Pasadena, CA 91109 | ------------------------------ Date: 18 Oct 90 01:33:07 GMT From: swrinde!zaphod.mps.ohio-state.edu!samsung!munnari.oz.au!uhccux!tholen@ucsd.edu (David Tholen) Subject: Re: Venus/Magellan, poles In article JEFF@UTCVM.BITNET (Jeffrey R Kell) writes: > I read all the (various) definitions of "poles" and longitude direction, > spin, etc., but to ask a possibly silly question, HOW do you determine > where a longitude grid BEGINS? Find Greenwich, Venus? ( ;-) ) The choice is arbitrary. On the Earth, London was chosen because Britain was the main seafaring nation of the time, so their choice is the one that caught on. On the sky, the vernal equinox represents a logical, but arbitrary choice for the zero point of the right ascension grid. For Pluto, we've arbitrarily chosen the sub-Charon point to represent zero longitude. Should Charon be proven to have a non-circular orbit, then the sub-Charon point would wander around slightly, but the choice could be made more explicit by specifying that zero longitude corresponds to the sub-Charon point when Charon is at periapsis. ------------------------------ Date: 15 Oct 90 12:39:43 GMT From: mvb.saic.com!ncr-sd!ncrlnk!ncr-mpd!Mike.McManus@ucsd.edu (Mike McManus) Subject: More on OSC and Pegasus First of all, thanks for the replies to my post about info on Orbital Sciences Corp. Thanks to your help, my wife dazzled `em during her interview, and will be starting work in their Boulder office next week (she sends her thanks). Secondly, as to what they do in the Boulder office: a little of everything, but for the most part, it is controls and guidance work for both Pegasus and the OSC/NASA TOS (Transfer Orbit Stage). I have more info on the TOS, if anyone is interested. Lastly, some info from a glossy pamphlet my wife picked up on here interview which discusses Pegasus. I'm not going to quote the whole thing, but here's the highlights (note that spelling errors are not my fault, blame them on network spooks :-). "System Description - The Pegasus flight vehicle is 49.2 ft. long and 50 in. in diameter, and has a gross weight (excluding payload) of approximately 41,000 lb. A delta wing with a 22-ft span and three 5-ft span moveable control fins are mounted on the first stage. Pegasus is carried aloft by a conventional transport or bomber-class aircraft to level flight conditions of 40,000 ft. and mach 0.8. After release from the aircraft and ignition of its first stage motor, the vehicle's autonomous flight control system provides guidance through the required suborbital or orbital trajectory. Pegasus can deliver spacecraft weighing up to 900 lb. into low Earth orbits or launch payloads up to 1500 lb. on suborbital, high Mach number cruise or ballistic flights. Spacecraft as large as 72 inches long and 46 inches in diameter can fit within the standard Pegasus payload fairing. In addition, Pegasus can accommidate three-axis, gravity-gradient or spin-stabilized spacecraft or multiple smaller satellites on a single launch." There are several pictures, including an artist's rendition of "Deployment of Pegasus from a commercial transport aircraft", which shows an aircraft with a specialized mount on the bottom dropping Pegasus (maybe someday this will be as common as sending US Mail on commercial airlines!). Included on the glossies was what appears to be their "corporate battle cry": "American Ingenuity Rises to the Challenge of Space". Here, here! -- Disclaimer: All spelling and/or grammar in this document are guaranteed to be correct; any exseptions is the is wurk uv intter-net deemuns,. Mike McManus Mike.McManus@FtCollins.NCR.COM, or NCR Microelectronics ncr-mpd!mikemc@ncr-sd.sandiego.ncr.com, or 2001 Danfield Ct. uunet!ncrlnk!ncr-mpd!garage!mikemc Ft. Collins, Colorado (303) 223-5100 Ext. 378 ------------------------------ Date: 15 Oct 90 03:09:09 GMT From: van-bc!rsoft!mindlink!a752@uunet.uu.net (Bruce Dunn) Subject: Re: Man-rated SRBs > gary@ke4zv.UUCP writes: > There are also a lot less things to go wrong in solids. There are no > turbo pumps, no complex valves and plumbing, no cryogenic liquids to > handle, no complex electronic control system to fail, just light and > go. Admittedly the shuttle's SRBs are poorly designed, but in general, > solids are the most reliable rockets we know how to build. I can remember reading an article written during the development program for the Saturn rocket which bemoaned the fact that liquid fuel rockets had been selected for the moon shot. At that time, NASA was snarled in the development problems of the F-1 engine and the thrust of the article was that solids were simple, reliable, and easily scaled up and should have been selected for the first stage of any moon vehicle. How times change! -- Did you hear the joke about the scientist whose wife had twins? - He baptized one and kept the other as a control. Bruce Dunn Vancouver, Canada a752@mindlink.UUCP ------------------------------ Date: 18 Oct 90 11:39:25 GMT From: att!cbnewsl!jfbn@ucbvax.Berkeley.EDU (james.f.burnell) Subject: Re: Pioneer 11 Update - 10/17/90 In article <1990Oct17.160629.26359@jato.jpl.nasa.gov>, baalke@mars.jpl.nasa.gov (Ron Baalke) writes: > > The Pioneer 11 spacecraft emergency continues. Yesterday, the 70 meter > antenna in Spain used it high power transmitter at 400 kw, and Ames Research > Center reported receiving telemetry intermittently for 8 minutes, 11 minutes, > 8 minutes and 19 minutes. The 70 meter station in Goldstone also provided > uplink support at 400 kw. The station was able to verify a 3-way downlink > with the 70 meter antenna in Spain, although receiver lock remained > intermittent. The maximum AGC (Automatic Gain Control) was at -172 DBM. > There was no telemetry data acquired during this pass. Was the loss of the Pioneer 11 signal at this time expected, considering the age of the spacecraft (loss of output of the RTG), limited power of its transmitter and its extreme distance? Is the loss of signal premature, or is a failure of some sort suspected? Jim Burnell AT&T Bell Labs ------------------------------ Date: 17 Oct 90 15:57:47 GMT From: julius.cs.uiuc.edu!zaphod.mps.ohio-state.edu!sdd.hp.com!elroy.jpl.nasa.gov!jato!mars!baalke@apple.com (Ron Baalke) Subject: Re: planetary north and names In article <7446.271c31ce@uwovax.uwo.ca> 17001_1511@uwovax.uwo.ca writes: >Regarding two recent postings: > >Latin names on planets are useful when dealing with an international >community of scientists. How can we use 'vernacular' names like 'Mariner >valleys' in an international setting without being offensive? Look at >medical terminology for all those squishy things inside us, or the latin >names of genera and species of living things - latin is not really a dead >language in science after all. Besides, it is just as easy to learn words >like 'tessera' or 'tholus' as simple terms like 'graben' or 'caldera', >without thinking of them as words in a foreign language. > The IAU has adopted a theme for Venus where most of its features are name after women. And if you look real close at the names, you will realize that the feature are named after famous dead women. The feature name has two parts; the first part is the female name, the second part is the feature. Example: Aphrodite Terra. Here is a list of the feature names used for Venus. Feature Definition ------------------------------------------------------------------------- Chasmata Canyons Colles Small hills, knobs Coronae Ovoid-shaped features Craters Craters Dorsa Ridges Lineae Elongated markings Montes Mountains Paterae Irregularly shaped craters Planitiae Low Plains Planum High Plain Regiones Areas of moderate relief Rupes Scarps (a cliff or steep slope) Tesserae Polygonal ground, tiles Terrae Continents Tholi Domical hills Incidently, using the Venera 15 and 16 data, the Soviets named two craters Resnick Crate and McAuliffe Crater, after the two women in the Challenger accident. ___ _____ ___ /_ /| /____/ \ /_ /| | | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov ___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov /___| | | | ___/ | |/__ /| M/S 301-355 | |_____|/ |_|/ |_____|/ Pasadena, CA 91109 | ------------------------------ Date: 16 Oct 90 21:58:14 GMT From: visix!amanda@uunet.uu.net (Amanda Walker) Subject: Re: Reflexes (teleoperators) In article <9010161901.AA16524@cmr.ncsl.nist.gov> roberts@cmr.ncsl.nist.gov (John Roberts) writes: >I've often wondered about that. How can a conscious command from the brain >suppress a reflex action that would normally be triggered before the stimulus >even reaches the brain? As I remember, some reflex arcs contain what could be called "cortical overrides," or neurons which, when activated, inhibit the normal reflex and allow the stimulus to be handled higher up in the nervous system. The only one I can think of is the infant suckling reflex, but I'm pretty sure there are others. The basic disadvantages of such overrides are that (a) real-time response suffers, since the loop has been lengthened again, and (b) most of them (aside from some infant relfexes) can only be overridden when the stimulus is anticipated, since they tend to "spring back". However, reflexes have a whole range of reactions sites and associated time delays. Cerebellar motor skills, for example, are slower than spinal reflexes but still faster than conscious processing. Using our current analogy, this is like being able to download code for specific tasks into the remote (i.e., "training"). -- Amanda Walker amanda@visix.com Visix Software Inc. ...!uunet!visix!amanda -- Marching to a different kettle of fish. ------------------------------ Date: 17 Oct 90 16:23:59 GMT From: swrinde!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!utzoo!henry@ucsd.edu (Henry Spencer) Subject: Re: Ulysses Update - 10/16/90 In article <9010170956.AA20378@thep.lu.se> magnus@thep.lu.se (Magnus Olsson) writes: >What kind of observations will Ulysses perform at Jupiter? Much the same as it will perform in the polar regions of the Sun: fields and particles work. It has no imaging system. -- "...the i860 is a wonderful source | Henry Spencer at U of Toronto Zoology of thesis topics." --Preston Briggs | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: 16 Oct 90 14:57:15 GMT From: sdd.hp.com!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov!baalke@ucsd.edu (Ron Baalke) Subject: Pioneer 11 Update - 10/16/90 Pioneer 11 Update October 16, 1990 The Pioneer 11 emergency continues. The 70 meter antennas in Spain supported downlink yesterday, and there has been no change to the status of the spacecraft. The same antennas will be used today to provide a 400 kw uplink. For those of you unfamiliar with Pioneer 11 or need their memory jogged, here is an article posted by Peter Yee last spring when Pioneer 11 left our solar system. ------------------------------------------------------------------------ PIONEER 11 PASSES NEPTUNE'S ORBIT, LEAVES SOLAR SYSTEM March 1990 Pioneer 11 today will cross the orbit of Neptune and become the fourth spacecraft to leave the solar system, providing a coda to humanity's first major planetary explorations. Pioneer 11 will join Pioneer 10 and Voyagers 1 and 2 in searching for the heliopause, the point at which the Sun's electromagnetic influence gives way to the galaxy's influence. As it crosses Neptune's orbit, Pioneer 11 will be 2.8 billion miles from the Earth. Neptune's orbit currently marks one measure of the expanse of the solar system because, for the next 12 years, Pluto's eccentric orbit carries it inside Neptune's path. Some scientists refer to the heliopause as the edge of the solar system. By that definition, all four spacecraft are still within the solar system. Launched in 1973, Pioneer 11 provided scientists with their closest view of Jupiter, passing within 26,600 miles of the cloud tops in December 1974. The close approach and the spacecraft's speed of 107,373 mph, by far the fastest speed ever reached by a man-made object, hurled Pioneer 1.5-billion miles across the solar system toward Saturn. Before reaching Saturn in 1979, Pioneer 11 reached an inclination of 17 degrees above the solar equatorial plane, high enough to illuminate the true character of the sun's magnetic field. Now 780 million miles above the ecliptic plane where most of the planets orbit the sun, the spacecraft recently showed that many of the solar cosmic rays in the heliosphere originate outside the Sun's atmosphere in the interstellar gas, the space between the stars. Pioneer 11 flew to within 13,000 miles of Saturn and took the first close-up pictures of the planet. Instruments located two previously undiscovered small moons and an additional ring, charted Saturn's magnetosphere and magnetic field and found its planet-size moon, Titan, to be too cold for life. Pioneer 11, which will traverse interstellar space in the same direction as the Sun moves, continues to return good data, but in 3 years, operating the radio transmitter and scientific instruments simultaneously will be difficult, says NASA Project Manager Richard Fimmel. Technical adjustments may extend the craft's life through 1995. Pioneer 10, with a stronger power supply, may return data through the year 2000, which would extend its original 30-month design life to 28 years. In June 1983, Pioneer 10 made history by becoming the first human artifact to leave the solar system, travelling in the direction opposite Pioneer 11's path. Today, Pioneer 10 will be 4.5 billion miles from Earth. Returning data to Earth at the speed of light requires 6 hours, 36 minutes. Pioneer 10 continues to search for the heliopause for very long-wavelength gravity waves that would further understanding of Einstein's Theory of Relativity and for evidence of a 10th planet. The Pioneers are managed by the Ames Research Center, Mountain View, Calif., for NASA's Office of Space Science and Applications. The spacecraft were built by TRW Space & Technology Group, Redondo Beach, Calif. ___ _____ ___ /_ /| /____/ \ /_ /| | | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov ___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov /___| | | | ___/ | |/__ /| M/S 301-355 | |_____|/ |_|/ |_____|/ Pasadena, CA 91109 | ------------------------------ End of SPACE Digest V12 #467 *******************