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 ; Thu, 25 Oct 1990 02:32:26 -0400 (EDT) Message-ID: Precedence: junk Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Thu, 25 Oct 1990 02:31:22 -0400 (EDT) Subject: SPACE Digest V12 #487 SPACE Digest Volume 12 : Issue 487 Today's Topics: Re: Pluto Re: Mammoth Magellan Data Re: Theories needed on life Hubble Space Telescope Update - 10/19/90 Re: Pioneer 11 article 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: 22 Oct 90 19:37:47 GMT From: comp.vuw.ac.nz!bankst@uunet.uu.net (Timothy Banks) Subject: Re: Pluto In article <1990Oct22.135534.5505@jato.jpl.nasa.gov> baalke@mars.UUCP (Ron Baal >I did a little further research on this. In the 1990 Astronomical Almanac, >page F2, it lists Pluto of having a 94 degree orbital inclination to the >planetary equator of 1950. In the book called "Planets Beyond, Discovering >the Outer Solar System", 1990 edition, page 296, Pluto is also listed as >having a 94.0 degree inclination of equator to orbit. However, in the >"The New Solar System", 3rd edition, page 291, Charon is listed as having >an orbital inclination of 98.8 degrees. > In Marciallis (_A.J_, 95(3), pp941, 1988) the Harrington and Christie polynomial for Pluto's sub earth latitude is given as jo = 106 (deg) j = jo - ( 2.2 * T ) - ( 0.005 * T * T ) in deg i = j + 1.8 * ( 2 * pi * ( t - 0.6 )) in deg where j is the heliocentric inclination, i is the apparent geometric inclination, T is the epoch measured from 1980.0, and t is the fractional year. Buie and Tholen (1989) in their Figure 1 compare this polynomial with the orbital calculation based on the satellite orbit of Tholen and Buie, which shows that for around now the two methods are very close. I hope that this might help with things! However, I stress that this is not my field at all, and in now way is this meant as a slight. I have great respect for Dr Tholen's work with Pluto, and enjoy Ron's postings (Thanks Ron - keep the good work up). -- ------------ Timothy Banks, Physics Department, Victoria University of Wellington, NZ. Bankst@rata.vuw.ac.nz;astrofiz@rs1.vuw.ac.nz;astrofiz@vuwst2.vuw.ac.nz. "He's dead, Jim!" "OK, you take the tricorder - I'll take the wallet!" ------------------------------ Date: 22 Oct 90 18:56:45 GMT From: mojo!SYSMGR%KING.ENG.UMD.EDU@mimsy.umd.edu (Doug Mohney) Subject: Re: Mammoth Magellan Data In article <1990Oct22.034440.937@jato.jpl.nasa.gov>, baalke@mars.jpl.nasa.gov (Ron Baalke) writes: >In article <1990Oct21.193411.20391@elroy.jpl.nasa.gov> pjs@euclid.jpl.nasa.gov writes: >>A graph on a nearby wall states that around March 1991, the >>data returned from Magellan will exceed that returned by all >>other planetary probes combined (pushing 1 trillion bits). >> >>Hmm, let's see, ftp'ing over a 56kbaud link... :-) Sounds like a good idea for pushing FDDI and other fast goodies on a national scale. >The Magellan data will be stored on 60+ CD-ROMs. One CD-ROM holds >680 megabytes of data. This is only after 8 months of mapping. Then when >you include the extended mission.... Yes, but do K-tel or DAK industries have the rights to distribute them? :-) ------------------------------ Date: 22 Oct 90 03:04:56 GMT From: van-bc!ubc-cs!news-server.csri.toronto.edu!utgpu!cunews!cognos!dgbt!rick.doc.ca!calvin.doc.ca!andrew@ucbvax.Berkeley.EDU (Andrew Patrick) Subject: Re: Theories needed on life In article <4678@optilink.UUCP> cramer@optilink.UUCP (Clayton Cramer) writes: >In article <1990Oct18.213753.34575@eagle.wesleyan.edu>, dlinder@eagle.wesleyan.edu writes: >> Could someone theorize on what humanoid life would be like on a planet 3 or 4 >> times the size of the Earth. I'm looking for theories on body structure, >> societies, technology, psychology, etc. Thanks, I appreciate any speculation. >> >> dml > >Short. Squat. Massive limbs. Leg bones of tremendous density and >thickness. Massive muscles to move those heavy and strong bones. >Enormous calorie requirement to operate those bodies. A great fear >of heights. :-) Sounds like a dinasour. Hum... I wonder if there is a new theory here somewhere. Is the earth shrinking in size? Perhaps the earth was much larger and when it shrunk the dinosaurs perished or simply slipped from the gravitational pull. My son has always wondered why they were so big! Lotsa :-)'s -- Andrew Patrick, Ph.D. Department of Communications, Ottawa, CANADA andrew@dgbt.doc.CA andrew@doccrc.BITNET HDTV: higher resolution, improved colour, wider screen, "sit-com" reruns. What's wrong with this picture? ------------------------------ Date: 24 Oct 90 01:11:50 GMT From: sdd.hp.com!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov!baalke@ucsd.edu (Ron Baalke) Subject: Hubble Space Telescope Update - 10/19/90 The following is forwared from Ron Polidan, astronomer on the HST team ------------------------------------------------------------------------ HST Status Report October 19, 1990 Current Status and Summary All has not gone well with the SAGA (Solar Array Gain Augmentation) software on HST. It does appear that the software has greatly reduced the 0.1 Hz oscillation produced by the solar arrays but it apparently was forcing the gyros into "high mode" much more frequently than desired. The SAGA is currently disabled. Testing of the SAGA software will continue to gather additional data but it seems unlikely that this software will be kept on the spacecraft in its present form. Since my last report a week ago the Astrometry team has been using the FGS's (Fine Guidance Sensors) to their first SAO (Science Assessment Observation) -- Duplicity Among Hyades Stars, with mixed results, GHRS (Goddard High Resolution Spectrograph) attempted to get an SAO observation of alpha Tau, but observation was unsuccessful due to a failure of the FGS's to acquire guide stars (incorrect guide star thresholds). The rest of the time HST was performing various SI (Scientific Instrument) tests, these, in general, went well. PCS (Pointing Control Subsystem) The goal of the SAGA software was to remove the oscillations seen in the HST pointing that are produced by thermal gradients warping the SPA's (Solar Power Arrays). Testing of the SAGA involved enabling and disabling it for periods of time and followed by comparative analyses of performance. The installation went rather smoothly. After a few days of testing a number of things became clear. First, the SAGA was very successful in removing the 0.1 Hz disturbance; the estimate was a factor of 30 reduction in amplitude. With this disturbance gone the other oscillation frequencies known to exist in the data (ranging from ~0.3 to 0.6 Hz) were more visible but not amplified. Unfortunately, the SAGA was frequently forcing the gyros out of the "low mode" state necessary for science operation and into a "high mode" state. With the gyros in the high mode state there there is also a probability of a safing event. The frequency of gyro high mode transitions was high enough to make it clear that the SAGA fix will have to be reexamined. In the course of the SAGA testing it was discovered that one part of the SAGA software, a torque limiting package, was not disabled when the rest of the SAGA was turned off. It was also noted that with the SAGA off some gyro problems were still occurring, suggesting that the torque limiter was part of the problem. It was then discovered that the while the torque limiting software could not be fully disabled it could be "patched" to effectively remove it form the system. This was quickly done and the gyro problems disappeared. At the moment plans are to continue testing of the SAGA but in a manner that will have minimum impact of other HST operations. Discussions and analyses are continuing but it appears unlikely that the current SAGA software will be kept on the spacecraft. It will probably be at least next week (pending the test schedule) before we have some definitive statements on the SAGA and its problems. Nothing new with regards to the FHST's (Fixed Head Star Trackers) or the FGS's since my last report. HST Focusing and Image Quality Nothing fundamentally new here since mid-September. A few revised numbers: the primary mirror conic constant: values range from -1.0145 to -1.0125 and appear to be converging. Error in the field lens: 1.33 +/- 0.05. ERO (Early Release Observations) and SAO Programs Two new SAO/ERO observations were attempted over the past week: the Astrometry team proposal looking at "Duplicity Among Hyades Stars" and a GHRS team proposal studying the "Chromosphere of Alpha Tauri." The Astrometry proposal is the second of three runs, the final run is scheduled for the SMS (Science Mission Specification) beginning on 29 October. At this early stage in the proposal the only comment that has been made is that "results are mixed." The results of the GHRS alpha Tau proposal were much less than "mixed" -- no data on alpha Tau was obtained. No guide stars were acquired and the star was never placed in the instrument aperture. It appears that incorrect FGS thresholds for the acquisition were in the SMS. This proposal will be rescheduled. Nothing additional on any of the earlier SAO/ERO observations. (Remember beginning with this next report I will list only new SAO/ERO observations or updates on old observations reported in earlier Status Reports.) Below is a list of the recent SAO/ERO observations and those planned in the next two weeks. AST (Astrometry Team): o Duplicity Among the Hyades (SAO) -- first two parts completed (no assessment), final run scheduled for the week of 29 October. o Orbital Parameters of Known Binaries -- scheduled for the week of 29 October. FOC (Faint Object Camera): o No new observations or results. FOS (Faint Object Spectrograph): o Imaging of NGC 1566 with the PC (SAO) -- scheduled for 27 October. o Helium in the Early Universe (target UM 675) (SAO) -- scheduled for 28 October (this is the first FOS instrument SAO/ERO observation). o Red Side Spectrophotometry of NGC 1068 -- scheduled for the week of 29 October. GHRS: o Chromosphere of Alpha Tau -- Failed, no guide stars (will be rescheduled) o Circumstellar Matter Around Beta Pictoris -- scheduled for 23 October HSP (High Speed Photometer): o No new observations. WFPC (Wide Field/Planetary Camera): o No new observations or results. SMS's All is going reasonably well. Most activity in the current SMS's was directed toward the SAGA installation and testing. Beginning Monday (22 October) we begin an SMS that contains OTA (Optical Telescope Assembly) image characterization, an FOC mini-sweep image characterization and the HARP (Hubble Aberration Recovery Program) proposal for further characterization of the WFPC. Also included in this SMS are FOC, FOS, and HSP instrument testing, the GHRS SAO observation of Beta Pic, and an OTA mini-OFAD (Optical Field Angle Distortion) proposal. The following SMS (29 October) has more SI testing, AST and FOS SAO/ERO observations, more FOC mini-sweep image characterization, a desorption monitoring proposal, and a WFPC UV Flood guiding test. SI's There is a pointing problem that is affecting all SI's to some degree. It appears that there is an uncertainty in the pointing accuracy of HST with respect to the SI apertures/field-of views. The size of the uncertainty is 2-4 arc seconds, a rather large error compared to most of the apertures. The belief is that the origin of the error is in the poor FGS to FGS alignment. A new FGS to FGS alignment is scheduled for the week of 5 November. Reanalysis of earlier (poor) data is also in progress -- a bug was found in the earlier reduction software. AST continues to work on understanding the FGS performance and problems. They have developed a "9 Points of Light" proposal (scheduled for the day 323, 26 November SMS) that does a detailed investigation of focal positions within a given FGS pickle and allows intercomparison of all three FGS pickles. FOC continues to function well with essentially no instrument problems. FOS has obtained their first external spectrum (Red Side) and, except for the magnetic shielding problems, have no significant instrument anomalies. GHRS is the most advanced of the SI in terms of OV/SV proposals completed with all of their OV proposals and some SV proposals finished. Unfortunately, the same cannot be said for their SAO/ERO observations, none of those attempted have been fully successful (see above and my previous report). HSP is advancing instrument testing with the exception of the PMT, VIS, and POL detectors until modifications to the bright earth avoidance angles are resolved. WFPC has been relatively quiet recently -- no major instrument problems have been reported. Ron Polidan ___ _____ ___ /_ /| /____/ \ /_ /| | | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov ___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov /___| | | | ___/ | |/__ /| M/S 301-355 | |_____|/ |_|/ |_____|/ Pasadena, CA 91109 | ------------------------------ Date: 23 Oct 90 22:20:03 GMT From: mnetor!utzoo!henry@uunet.uu.net (Henry Spencer) Subject: Re: Pioneer 11 article In article <6469@uceng.UC.EDU> dmocsny@minerva.che.uc.edu (Daniel Mocsny) writes: >1. What was the original design life of the spacecraft? Long enough to get to Saturn, which was maybe five years. (Don't remember.) >2. Since the end of their primary missions, how valuable has been >the data returned by the Pioneers and Voyagers? > >3. In particular, have these "used spacecraft" been instrumental in >major discoveries after the ends of their primary missions? The data has been useful but not Earth-shaking. The single most prominent result is fairly strong negative evidence that there is no major tenth planet. (The effects on the Pioneer/Voyager trajectories would have been seen by now.) The big news will be hitting the heliopause (the boundary of the Sun's atmosphere), but the Voyagers are likely to get there first. >4. As the RTG's run down and transmission distances grow, how long >can NASA realistically hope to maintain useful contact with these >craft? ... The limiting factor for both the Pioneers and the Voyagers is the lifetime of the RTGs. Barring failures, the Pioneers will be in touch for about another decade and the Voyagers for about another three. Improvements in communications and such have helped ensure that that isn't the bottleneck. >5. I know we can't predict discoveries, but would anyone care to >take a stab at what we're going to lose by Pioneer 11 biting the >(star)dust? *Probably* nothing massive. But as you observe, the big discoveries are the things you can't predict. That side, the main loss will be fields- and-particles data from a region that won't be visited again for a long time. >6. How come NASA let the primary contractor get away with no >field service contract? ;-) I mean, I recently saw an ad from >TRW service, saying they "do it all"! I believe the contract specified depot service only, with the customer responsible for bringing it in. :-) -- The type syntax for C is essentially | Henry Spencer at U of Toronto Zoology unparsable. --Rob Pike | henry@zoo.toronto.edu utzoo!henry ------------------------------ End of SPACE Digest V12 #487 *******************