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, 16 Jan 91 21:25:14 -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, 16 Jan 91 21:25:10 -0500 (EST) Subject: SPACE Digest V13 #055 SPACE Digest Volume 13 : Issue 55 Today's Topics: Re: LO2/LH2 in Shuttle Payload Bay Re: LO2/LH2 in Shuttle Payload Bay What is cosmological constant? Re: Nuclear deep space power sources Re: Cameras in 0G, was: Re: MIR Vacation Re: Humanity's Launch Window HUBBLE REPORT Re: some questions Re: THE BLUE PLANET Ulysses Update - 01/15/91 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 ---------------------------------------------------------------------- Date: 16 Jan 91 04:53:22 GMT From: snorkelwacker.mit.edu!usc!wuarchive!cs.utexas.edu!news-server.csri.toronto.edu!utzoo!henry@bloom-beacon.mit.edu (Henry Spencer) Subject: Re: LO2/LH2 in Shuttle Payload Bay In article <2180.27932817@ofa123.fidonet.org> Wales.Larrison@ofa123.fidonet.org (Wales Larrison) writes: > Magellan, from my recollection, was never planned to use a >Shuttle-Centaur. The use of the TOS stage was allowed when they >removed the requirement to circularize the orbit at Venus ... ??? Wales, I think you need to check the references on this. Magellan has never used a TOS; it went up on an IUS. And a quick look through the files confirms my recollection: Magellan was originally slated to be the first NASA customer for Centaur G (as opposed to the bigger G-prime planned for Ulysses and Galileo). And Magellan, as opposed to its predecessor VOIR, has always planned an elliptical orbit. >[Ulysses] The Delta-VEGA maneuver used was a god- >send to them. Again, ??? Unless I am badly mistaken, Ulysses is going direct to Jupiter, no delta-VEGA involved. Only Galileo gets to bat around the inner system for a while first. >... Turns out Rockwell's Space Transportation Systems >Division did a study on it in about 1987, which was supposedly the >analysis which bumped the Centaur off Shuttle. Hope you can turn that up; I am very interested to hear what it says. -- If the Space Shuttle was the answer, | Henry Spencer at U of Toronto Zoology what was the question? | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: 15 Jan 91 05:11:08 GMT From: snorkelwacker.mit.edu!usc!elroy.jpl.nasa.gov!zardoz.cpd.com!dhw68k!ofa123!Wales.Larrison@bloom-beacon.mit.edu (Wales Larrison) Subject: Re: LO2/LH2 in Shuttle Payload Bay >So how did solid rockets -- which one would expect to weigh more, >given their considerably lower specific impulse -- satisfy those >weight limits for launching two out of the three original Shuttle- >Centaur payloads? Both Ulysses and Magellan, originally both slated >for S-C, flew their original flight plans, or close approximations >thereto, with solids. How did those missions meet the weight limits >if Shuttle-Centaur versions of those missions couldn't? Funny you should ask Henry. If you check my previous posting from yesterday I gave a brief synopsis of the history of the Galileo mission with the C3 energy terms (as best as I could remember them) from the different Galileo opportunities. To summarize - the original Galileo plan used a very favorable launch window in 1982 which would have used a Mars swingby maneuver to significantly reduce the energy required in the orbit. By 1986 or so, this favorable alignment of Earth, Mars, and Jupiter was lost, forcing the mission to accomodate a much higher energy requirement. Magellan, from my recollection, was never planned to use a Shuttle-Centaur. The use of the TOS stage was allowed when they removed the requirement to circularize the orbit at Venus (originally the mission planned for circularization of the spacecraft in Venusian orbit). Using the inclined elptical orbit which Magellen is now in, allowed a dual use of the Radar mapping antenna for Earth-pointing communications, which did reduce weight and complexity of the mission. Ulyses (I still prefer ISPM) is a whole 'nother kettle of fish however. (Again, you must pardon me from working from memory - my files got dumped when my company got out of the upper stage business about 4 years ago). The original mission plan for Ulyses was to use the Galileo opportunity with a Mars swingby maneuver. Their problem was not only getting to Jupiter, but they needed somewhere around 15,000 fps velocity at Jupiter to do the 90 deg plane change, even with a gravity assist by Jove. (:-) Their required C3 jumped to about 70 km2/sec2, without the Mars assist, compared to about 55 for Galileo. (They were only able to originally plan to do the mission by greatly reducing their weight compared to Galileo). With the loss of the 1984 opportunity, they were really stuck. Prior to the Centaur decision all sorts of weird ideas were floating around - like reducing the vehicle weight (again), or adding additional solid stages on the IUS stack. The Delta-VEGA maneuver used was a god- send to them. BTW, I went into our corporate library and had the reference librarian run a lit search on the Safety aspects of the Centaur integration. Turns out Rockwell's Space Transportation Systems Division did a study on it in about 1987, which was supposedly the analysis which bumped the Centaur off Shuttle. To make a long story short - I called the analyst who wrote the report, and he's getting me a copy of the report. Unfortunately, he's out of town this week (I caught him on his way out the door to the airport to DC), but we've set up a time to talk next week about the issue. Since the Centaur has been pulled from the orbiter, there seemed more than willing to talk. I'll keep the net posted, as I find out more of what the analysis showed. ------------------------------------------------------------------ Wales Larrison Space Technology Investor -- Wales Larrison Internet: Wales.Larrison@ofa123.fidonet.org Compuserve: >internet:Wales.Larrison@ofa123.fidonet.org -------------------------------------------------------------------------- ------------------------------ Date: 15 Jan 91 22:36:17 GMT From: bu.edu!rpi!zaphod.mps.ohio-state.edu!wuarchive!kuhub.cc.ukans.edu!mcginnis@bloom-beacon.mit.edu Subject: What is cosmological constant? Can someone give me a brief explanation of "cosmological constant"? I have the understanding that this is a base energy density for "empty" space; as opposed to a base energy level (vacuum energy level) for "empty" space. Is this correct? To what would this base energy level be due? Uncertainty leading to a background cloud of paired virtual particles? Thanks. Mike McGinnis "Rust never sleeps." Academic Computing Center -The Second Law of University of Kansas Thermodynamics Lawrence, Kansas 66045 ------------------------------ Date: 16 Jan 91 12:44:44 GMT From: astroatc!jjohnson@speedy.wisc.edu (Joe Johnson) Subject: Re: Nuclear deep space power sources i believe that most if not all of the deep space RTG's use Plutonium 238 as the heat source. Pu 238 has a half-life of 86 years and decays by emitting a 5.6 MeV alpha particle. According to my source (Nuclear Heat Transport by M. M. El-Wakil) Pu 238 has a density of 12.5 g/cm^3 which gives a peak power density of 6.9 W/cm^3 (this is the thermal power density, the electrical conversion has not been taken into account). joe -- -------- jjohnson%astroatc.uucp@cs.wisc.edu | The cemeteries are full of indispensable {...}!uwvax!astroatc!jjohnson | men. --Georges Clemenceau ------------------------------ Date: 15 Jan 91 21:04:16 GMT From: sun-barr!newstop!exodus!concertina.Eng.Sun.COM!fiddler@apple.com (Steve Hix) Subject: Re: Cameras in 0G, was: Re: MIR Vacation In article <92@hobby.ukc.ac.uk>, has@ukc.ac.uk (H.A.Shaw) writes: > > Whats all this about modifications for 0G? [...] > [...] I have around 20,000 slides in my current collection and I've never > knowingly lost a shot because of gravity. What difference does gravity make? > > Maybe it makes using a tripod a little more tricky :-) > > This sounds like the $483 space rated hammer again to me! As I (dimly) recall, space-rating a camera system has little do with gravity. The problems that concerned NASA had more to do with the cameras operation in vacuum (outgassing, lubrication, thermal response, etc.) than anything else. Some chemicals outgassing from the camera might have been a potential problem from a life-support angle, and evaporating lubricants could leave you with a non-functioning paperweight just when you didn't need one. -- ------------ The only drawback with morning is that it comes at such an inconvenient time of day. ------------ ------------------------------ Date: 15 Jan 91 22:05:48 GMT From: netcom!teda!bosart@apple.com (Donald R. Bosart) Subject: Re: Humanity's Launch Window ajs@hpfcdc.HP.COM (Alan Silverstein) writes: Humanity's Launch Window Alan Silverstein January 14, 1991 > *Thirty years*. That's about how long humanity's ``launch > window'' has been open. There are wonders beyond comprehension > awaiting us beyond our Earth. To achieve a toehold, a foothold, > on those riches requires enormous investment. It takes raw > materials and the technology to render them. It takes many, many > people, at peace with each other in a stable society, wealthy > enough to make investments whose return is measured in > generations. > In an actual article, I would expect more concrete examples of the benefits designed to mute space expansion critics... > Our precious Earth is crowded. Our raw materials are being > consumed. *Our launch window will close*. This needs expansion, and justification; Club of Rome, etc. > > *How long do we have?* It is anyone's guess. I think no more > than fifty years. Perhaps much less. After that -- no one, no > group, will have the resources, the time, the energy, to spare on Maybe. I think the more likely scenario is that another culture, perhaps Japanese will cross the threshold. I say this because we seem too pre-occupied with militarism and the Europeans with happenings east of them to have a PLAN for space. It is also possible to imagine a partial collapse (50%-90%) of humanity's world system, followed by "dark ages", followed by another expansion which might retain enough technology and know-how to make the leap to space. This is supportable by historical and biological evidence. Of course, there were once dinosaurs too! > > *Imagine it*. Nine billion years for Earth. An eighty year > launch window for humanity. Now *that* is the big picture. > Perhaps, in the long run, it is the only perspective that counts. A very good point! -- ------------------------------------------------------------------------------- Donald R. Bosart Teradyne EDA West !{decwrl, sun}!teda!bosart 5155 Old Ironsides Dr. 408-980-5264 Santa Clara, CA. 95054 ------------------------------ Date: 14 Jan 91 19:56:26 GMT From: mcsun!ukc!mucs!liv-cs!liv!eeet176@uunet.uu.net (Andrew Hartridge) Subject: HUBBLE REPORT Can anyone tell me (if it has been published yet) wether there is an electronic form of the Hubble primary mirror investigation panel report. If so can it be mailed or I can FTP it ??? If not can someone tell me the Report Ref. Number so I can get it on paper from the US Government Printing office (I presume it is they who publish it?) Thanks a lot ------------------------------------------------------------------------ | Andrew Hartridge | | "How do you feel today... | | | | UUCP: !mcvax!ukc!liverpool.ac.uk!eeet176 | | "Better ...... Better get | JANET: eeet176 @ uk.ac.liverpool.ibm | | bucket I'm gonna be sick | ANDREWH @ uk.ac.nsfnet-relay | | --- Mr Creosote | Handel anywhere on the Internet : Rooh | ------------------------------------------------------------------------ ------------------------------ Date: 16 Jan 91 17:25:32 GMT From: agate!bionet!uwm.edu!wuarchive!usc!jarthur!nntp-server.caltech.edu!rknop@ucbvax.Berkeley.EDU (Robert Andrew Knop) Subject: Re: some questions ephillip@magnus.ircc.ohio-state.edu (Earl W Phillips) writes: >1) Once I know the lat, long location of my site, how >do I translate these figures to decimal? Do you mean something like: lat = (deg + arcmin/60 + arcsec/3600) degrees long = [(deg + arcmin/60 + arcsec/3600)*(24/360)] degres ? -Rob Knop rknop@tybalt.caltech.edu ------------------------------ Date: 15 Jan 91 19:47:13 GMT From: hpfcso!hpfcdc!ajs@hplabs.hpl.hp.com (Alan Silverstein) Subject: Re: THE BLUE PLANET > ...THE DREAM IS ALIVE is now available on VHS cassette... I saw it last month at Kennedy Space Center for about $13, if I remember right. Surprisingly reasonable prices on all the "space stuff" for sale in the gift shop there. Stiff paper posters, 16x20 (?), for $3, for instance. > ...most IMAX theatres don't show this thrilling feature much anymore, > maybe because Challenger is such a big part of it. It runs continuously at the IMAX theater at KSC for $2.75 (I think). Such a deal. It appeared they had edited it a little since I last saw it in 1986, though. Specifically I thought they showed a little more of Judy Resnick earlier. ------------------------------ Date: 16 Jan 91 18:06:03 GMT From: snorkelwacker.mit.edu!usc!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov!baalke@bloom-beacon.mit.edu (Ron Baalke) Subject: Ulysses Update - 01/15/91 ULYSSES STATUS REPORT January 15, 1991 The following data was taken at 9AM (PST), January 14, 1991 on the Ulysses spacecraft: Distance from Earth 72,188,104 miles (116,175,492 km) Distance from Jupiter 346,548,247 miles (557,715,343 km) Velocity relative to the Sun 67,976 mph (109,396 kph) Velocity relative to the Earth 54,393 mph ( 87,537 kph) On January 8, a nominal slew maneuver was performed. On January 9, a BAM (Solar Wind Plasma instrument) matrix I reconfiguration was carried out. On January 10, Pseudo Spin scheduling tests were carried out. The Solar Aspect angle increased from 6.5 degrees on January 8 to 9.9 degrees on January 14. The Sun-Probe-Earth angle increased from 7.1 degrees on January 8 to 10.4 degrees on January 14 when Opposition occurred. The angle is now increasing again. A series of DSN (Deep Space Network) problems/errors occurred during this first week of routine operations. The data return was less than required. Actions have been taken to reduce the operator errors but some degree of station system failures must be expected in the future. Operations since January 11 have improved. Routine data gathering operations will continue together with experiment reconfigurations as required. Tape recorder operations based on recovering data acquired during the 16 hours out of view periods are continuing on a routine scheduled basis. ___ _____ ___ /_ /| /____/ \ /_ /| | | | | __ \ /| | | | 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 V13 #055 *******************