Return-path: X-Andrew-Authenticated-as: 7997;andrew.cmu.edu;Ted Anderson Received: from hogtown.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, 6 Feb 91 02:05:44 -0500 (EST) Message-ID: Precedence: junk Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Wed, 6 Feb 91 02:05:40 -0500 (EST) Subject: SPACE Digest V13 #119 SPACE Digest Volume 13 : Issue 119 Today's Topics: Magellan Images Re: space news from Dec 17 AW&ST Re: Fire in Space The edge of the solar system Re: Voyager CD-ROMs Administrivia: Submissions to the SPACE Digest/sci.space should be mailed to space+@andrew.cmu.edu. Other mail, esp. [un]subscription requests, should be sent to space-request+@andrew.cmu.edu, or, if urgent, to tm2b+@andrew.cmu.edu ---------------------------------------------------------------------- Return-path: X-Andrew-Authenticated-as: 0;andrew.cmu.edu;Network-Mail Date: 1 Feb 91 23:17:32 GMT From: elroy.jpl.nasa.gov!jpl-devvax!jato!mars.jpl.nasa.gov!baalke@ames.arc.nasa.gov (Ron Baalke) Organization: Jet Propulsion Laboratory, Pasadena, CA. Subject: Magellan Images Sender: space-request@andrew.cmu.edu To: space@andrew.cmu.edu ================= MAGELLAN IMAGES ================= I've placed six more Magellan images at the Ames site. You can get them via anonymous ftp at ames.arc.nasa.gov (128.102.18.3) in the directory pub/SPACE/VICAR. Again, thanks to Peter Yee for use of his disk space and computer system. There are now 8 Magellan images available, each one is about 1MB in size and they are in VICAR format. I've also added the captions that go along with each of the images. They are in a separate ASCII file with a .txt extension with filename matching the corresponding image. The captions are interesting to read by themselves, and I've appended them to the end of this posting. This weekend I will convert these same Magellan images into GIF format. ============================================================================= GOLUBKINA.IMG This three-dimensional representation of brightness variations in a Magellan radar image of Golubkina crater enhances the structural features of the crater. Golubkina is 34 km (20.4 miles) in diameter, and is located at about 60.5 degrees north latitude, 287.2 degrees east longitude. Golubkina is characterized by terraced inner walls and a central peak, typical of large impact craters on the Earth, Moon and Mars. The terraced inner walls form at late stages in the formation of an impact crater, due to collapse of the initial cavity formed by the meteorite impact. The central peak forms due to rebound of the inner crater floor. ============================================================================= DSNALL.IMG One of the most useful Magellan standard data products is the full resolution mosaic, the F-MIDR (Full-Resolution Mosaicked Image Data Record). These products are mosaics of about 500 km (300 mile) segments of 30 or more individual image strips. This is a partial F-MIDR made from orbits 376 to 399, obtained between September 15 and September 18, 1990, part of the first orbits in which the Magellan flight team operated the radar system in the mapping mode. The mosaic is centered at 27 degrees south latitude, 339 degrees longitude, in the Lavinia region of Venus. Three large impact craters with diameters ranging from 37 kilometers (23 miles) to 50 kilometers (30 miles) can be seen located in a region of fractured plains. The craters show many features typical of meteorite impact craters, including rough, radar-bright ejecta, terraced inner walls and central peaks. Numerous domes of probable volcanic origin can be seen in the southeastern corner of the mosaic. The domes range in diameter from 1-12 kilometers (0.6-7 miles), and some have central pits typical of volcanic shields or cones. Resolution of the Magellan data is about 120 meters (400 feet). ============================================================================= GUMBY.IMG On September 15, 1990, the Magellan spacecraft started radar operations for its mapping mission at Venus. This image is taken from the first set of radar data collected in the normal operating mode. These fault-bounded troughs were imaged by Magellan on orbit 147 on September 15, 1990. The image is of part of the Lavinia Region of Venus at 60 degrees south latitude, 347 degrees east longitude. The image is 28 kilometers (17 miles) wide and 75 kilometers (46 miles) long. This region is at the intersection of two tectonic trends. An extensive set of east-west trending fractures extends to the west (left) and a second set extends down to the south-southeast (lower right). The lines of pits suggest some igneous or volcanic activity accompanying the faulting. The prominent trough trending diagonally across the image is 5 kilometers (3.1 miles) wide and is 100 to 200 meters (300 to 600 feet) deep. ============================================================================= CHANNEL.IMG This Magellan image covers a region 77 kilometers (46 miles) wide and 85 kilometers (51 miles) high. This image shows part of a long, open channel at 76.5 degrees north latitude, 335 degrees longitude in the Vires-akka Chasma, about 100 kilometers (60 miles) north of Freyja Montes, in the Denitsa Region of Venus. The channel ranges in width from less than 1 kilometer (3300 feet) to 4 kilometers (2.4 miles). The portion of the channel visible in this scene is over 120 kilometers (72 miles) long. Longitudinal scour features are visible within the channel, particularly where it makes abrupt turns. The channel may have been carved by very low viscosity lavas that were able to remain fluid over great distances and thermally erode pre-existing terrain due to the extreme temperatures at Venus' surface. ============================================================================= X-CUT.IMG This is a Magellan radar image mosaic of part of the Lakshmi region of Venus. The mosaic is part of revolutions 390 and 391 acquired on September 17, 1990. The image is located at 30 degrees north latitude, 333.3 degrees east longitude, and is about 37 kilometers (23 miles) wide and 80 kilometers (48 miles) long. On the basis of Pioneer Venus and Arecibo data, it is known that the region shown is located on the low rise separating Sedna Planitia and Guinevere Planitia, and just to the west of Eistla Regio. The image shows two sets of parallel lineations which intersect almost at right angles. The fainter lineations are spaced at a regular interval of about 1 kilometer and extend beyond the boundaries of the image. The width of these faint lineations is at the limit of resolution of the best Magellan images. The brighter, more dominant lineations are less regular and appear in places to begin and end where they intersect the fainter lineations. It is not yet clear whether the two sets of lineations represent faults or fractures, but in other areas outside the image, the bright lineations are associated with pit-craters and other volcanic features. This type of terrain has not been seen previously, either on Venus or the other planets. Resolution of the Magellan data is about 120 meters (400 feet). ============================================================================= ODDIMPACT.IMG On September 15, 1990, the Magellan spacecraft started radar operations for its mapping mission at Venus. This image is taken from the first set of radar data collected in the normal operating mode. This Magellan radar image is of an impact crater in the Navka Region of Venus. The image is a mosaic of data taken from orbits 376 and 377 on September 15, 1990. The crater is located at 334.5 E. longitude, 21.4 S. latitude, and is about 9 x 12 kilometers (5 x 7 miles) in size. This crater is very unusual, and is in some ways different from anything seen elsewhere in the solar system. It is fresh, with a sharp rim, terraces on the walls, and a well- developed ejecta blanket. The rim, however, is distinctly kidney- shaped rather than circular, and the crater's fresh appearance suggests, that it formed with that shape at impact. The ejecta blanket is markedly non-symmetric, with lobes extending to the north (top) and south (bottom) of the image, and a major extension stretching to the east (right). On the crater floor are several smooth, flat, dark regions. The asymmetric shape of the ejecta blanket has been observed on other planets and in impact experiments, and probably indicates that the impactor struck the surface at a low, oblique angle. The impactor would have been moving from west to east, sending ejecta lobes off to either side and a long streamer in the forward direction. The truly unusual aspect of the crater is its shape. One possible explanation is that the impactor broke up as it passed through the dense Venusian atmosphere, causing several large chunks of material to strike the surface almost simultaneously in an irregular pattern. The dark patches on the crater floor may be solidified pools of molten rock generated by the impact, or could be volcanic material extruded some time after the crater's formation. ============================================================================= DSNTALL.IMG The first 3 days (24 orbits) of radar mapping from the Magellan spacecraft have revealed the presence of a wide diversity of geologic features on the surface of Venus. This full resolution mosaic centered at 20 south latitude, 337.4 east longitude is located between Navka and Lavinia Planitia and covers a region 475 kilometers (285 miles) wide and 545 kilometers (330 miles) long. Analysis of this area from lower resolution Arecibo data show that this area is part of an extensive region identified as bright plains. The Magellan data reveal the detailed geologic characteristics of different landforms in these plains. Located along the left central edge of the image is a cluster of volcanic domes which range from 1.5 kilometers to 7.5 kilometers in diameter and cover a region 150 kilometers by 100 kilometers (90 miles by 60 miles). The domes and their deposits are located at the convergence of radar-bright lineaments which are interpreted to be faults and troughs. In some places the domes overlie the faults. The faults and troughs extend into the lower part of the image where they terminate against dark plains deposits and are cross cut at right angles by additional faults. These relations indicate that multiple episodes of faulting and volcanism have occurred. An irregular shaped impact crater (11 kilometers by 8 kilometers) (7 miles by 5 miles) located in the lower left corner of the image is interpreted to have formed by multiple impacts resulting from the breakup in the atmosphere of a larger impactor. An extremely radar-dark circular region located along the right central edge of the image is interpreted as a possible region of sedimentary deposits. ============================================================================= PAN10.IMG This image of the eastern edge of Alpha Regio, 30 degrees south latitude, 11.8 east longitude, was acquired on November 7, 1990. It shows seven circular domical hills averaging 25 kilometers (15 miles) in diameter and maximum heights of 750 meters (2475 feet). These features can be interpreted as viscous or thick eruptions of lava coming from a vent on the relatively level ground allowing the lava to flow in an even lateral pattern. The concentric and radial fracture pattern on their surfaces suggests if they are extrusive that a chilled outer layer formed then further intrusion in the interior stretched the surface. The domes may be analogous to volcanic domes on Earth. An alternative interpretation is that the domes are the result of shallow intrusions up-doming the surface layers. If they are intrusive, then magma withdrawal near the end of the eruptions then produced the fractures. The bright margins possibly indicate the presence of rock debris or talus at the slopes of the domes. Fractures on the surrounding plains are both older and younger than the domical hills. Resolution of the Magellan data is about 120 meters (400 feet). ___ _____ ___ /_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov | | | | __ \ /| | | | Jet Propulsion Lab | ___| | | | |__) |/ | | |___ M/S 301-355 | It's 10PM, do you know /___| | | | ___/ | |/__ /| Pasadena, CA 91109 | where your spacecraft is? |_____|/ |_|/ |_____|/ | We do! ------------------------------ Return-path: X-Andrew-Authenticated-as: 0;andrew.cmu.edu;Network-Mail Date: 30 Jan 91 19:20:35 GMT From: ucselx!sol.ctr.columbia.edu!zaphod.mps.ohio-state.edu!unix.cis.pitt.edu!pitt!nss!Paul.Blase@ucsd.edu (Paul Blase) Organization: The NSS BBS, Pittsburgh PA (412) 366-5208 Subject: Re: space news from Dec 17 AW&ST Sender: space-request@andrew.cmu.edu To: space@andrew.cmu.edu MV> Apollo 1 didn't kill the Apollo program because the Apollo MV> program was a political one, not a scientific one. We had the MV> Russians to beat. Nothing -- not launch pad fires, nor rocket MV> failures, nor bad weather -- was going to stand in our way of MV> beating those damn Russians. That ambition -- for better or MV> for worse -- is gone forever. Had Apollo 1 occurred today, the MV> result would be very similar to the Challenger aftermath. I would rather think that in about 10 years we'll be playing the same catch-up games with the Japanese. Their government (and, more importantly, industry) seems to be taking space industrialization very seriously. See the August 13 issue of AW&ST. --- via Silver Xpress V2.26 [NR] -- Paul Blase - via FidoNet node 1:129/104 UUCP: ...!pitt!nss!Paul.Blase INTERNET: Paul.Blase@nss.FIDONET.ORG ------------------------------ Return-path: X-Andrew-Authenticated-as: 0;andrew.cmu.edu;Network-Mail Date: 1 Feb 91 16:29:10 GMT From: voder!dtg.nsc.com!alan@ucbvax.Berkeley.EDU (Alan Hepburn) Organization: National Semiconductor, Santa Clara Subject: Re: Fire in Space References: <7332@crash.cts.com>, <10134@ncar.ucar.edu> Sender: space-request@andrew.cmu.edu To: space@andrew.cmu.edu In article <10134@ncar.ucar.edu> strandwg@ncar.ucar.edu (Gary Strand) writes: #> Dan Gookin # #> If figure if you lit a match, it probably would lack the familiar conical #> shape the flame has here on earth. In fact, I think it would look like a #> point of light or perhaps a spherical flame. # # Why? What effect does gravity have on the burning particles, relative to # the forces they feel from the other heated particles around them? I would # think that since gravity plays such a small role in what a flame looks # like, it would look the same on the Shuttle (say) as here on earth. #-- Wasn't this experiment run on the last Shuttle flight? At least, I thought I remembered hearing that one of the astronauts was going to try lighting a match, or a candle, to evaluate the effects of microgravity on a flame (a hot one, not a verbal one). -- Alan Hepburn "To treat your facts with imagination National Semiconductor Corp is one thing, but to imagine your facts Santa Clara, Ca is anothor." mail: alan@berlioz.nsc.com John Burroughs ------------------------------ Return-path: X-Andrew-Authenticated-as: 0;andrew.cmu.edu;Network-Mail Date: 30 Jan 91 19:11:46 GMT From: ucselx!sol.ctr.columbia.edu!spool.mu.edu!sdd.hp.com!zaphod.mps.ohio-state.edu!unix.cis.pitt.edu!pitt!nss!Paul.Blase@ucsd.edu (Paul Blase) Organization: The NSS BBS, Pittsburgh PA (412) 366-5208 Subject: The edge of the solar system Sender: space-request@andrew.cmu.edu To: space@andrew.cmu.edu JC> This is also noted in John Brandt's article on comets JC> in "The New Solar System" (228) who discusses Jan Oort's JC> conclusion that the "overwhelming majority of comets reside in JC> an essentially spherical cloud around the Sun with a radius of JC> perhaps 20,000 to 100,000 AU. (By comparison, the nearest srs JC> to the solar system, the Alphaha Centauri System, are some JC> 275,000 AU distant.)" JC> I suppose our spacecraft would yet have a way to go as JC> Pluto is only of the order of 40 AU! An AU is about 150 Gm JC> (150 million km). I have seen several articles about a planned NASA mission: the TAU probe (TAU stands for Thousand Astronomical Units). A very high tech device, the probe would use ion thrusters to move a telescope similiar to the Hubble out to 1k AU from the sun. Communications would be via laser link. The main missions would be to get accurate parallax measurements on distant stars and to check out the intersteller environment. Does anyone else know anything more about this? --- via Silver Xpress V2.26 [NR] -- Paul Blase - via FidoNet node 1:129/104 UUCP: ...!pitt!nss!Paul.Blase INTERNET: Paul.Blase@nss.FIDONET.ORG ------------------------------ Return-path: X-Andrew-Authenticated-as: 0;andrew.cmu.edu;Network-Mail Date: 1 Feb 91 15:59:11 GMT From: sdd.hp.com!cs.utexas.edu!news-server.csri.toronto.edu!helios.physics.utoronto.ca!ists!nereid!white@ucsd.edu (Harold Peter White) Organization: Institute for Space and Terrestrial Science Subject: Re: Voyager CD-ROMs References: <1991Jan28.055722.16167@jato.jpl.nasa.gov>, <1991Jan30.231628.6707@oakhill.sps.mot.com>, <2823@dftsrv.gsfc.nasa.gov> Sender: space-request@andrew.cmu.edu To: space@andrew.cmu.edu In article <2823@dftsrv.gsfc.nasa.gov> brotzman@nssdcb.gsfc.nasa.gov writes: >In article <1991Jan30.231628.6707@oakhill.sps.mot.com>, hunter@oakhill.sps.mot.com (Hunter Scales) writes... >>baalke@mars.jpl.nasa.gov (Ron Baalke) writes: >>> I've received a number of inquiries about the Voyager images available >>>on CD-ROMs. There are eight CD-ROMs that contain about 16,000 images taken >> And now, here is another question. After viewing some of the Saturn satellite images, there are two things I would like to determine that I can't seem to get from the header. Which way is north, relative to any specific ecliptic plane (ie., Earth's or Saturn's) and what is the sub-satellite latitude of the imaged object? In many cases, these can be estimated by looking at features apparent on the image, ie Saturn's rings, Titan's dark pole, etc. If possible however, I would rather see something a bit more formal, especially when looking at the satellites. Anybody know where I would obtain this information? Thanks in advance, H. Peter White white@nereid.sal.ists.ca Space Astrophysics Laboratory ------------------------------ End of SPACE Digest V13 #119 *******************