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 ; Wed, 14 Nov 1990 02:40:44 -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, 14 Nov 1990 02:40:13 -0500 (EST) Subject: SPACE Digest V12 #549 SPACE Digest Volume 12 : Issue 549 Today's Topics: Re: orbiting bodies Re: LLNL Astronaut Delivery (was Re: You Can't Expect a Space Station) New Shuttle Engines RadioM1/Rudak2 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 ---------------------------------------------------------------------- Return-path: X-Andrew-Authenticated-as: 0;andrew.cmu.edu;Network-Mail Date: 8 Nov 90 05:33:19 GMT From: swrinde!zaphod.mps.ohio-state.edu!pacific.mps.ohio-state.edu!linac!tellab5!balr!clrcom!rmartin@ucsd.edu (Bob Martin) Organization: Clear Communications, Inc. Subject: Re: orbiting bodies References: <129@ctbilbo.UUCP>, <1990Nov6.010422.26534@uokmax.ecn.uoknor.edu> Sender: space-request@andrew.cmu.edu To: space@andrew.cmu.edu In article <1990Nov6.010422.26534@uokmax.ecn.uoknor.edu> jabishop@uokmax.ecn.uoknor.edu (Jonathan A Bishop) writes: >pete@ctbilbo.UUCP (Pete Ritter) writes: > >Now, my question: >Are the forces that synchronized the Moon's rotation and revolution the same >forces that have nearly done so with Venus relative to the Sun? >Does this phenomena only happen in a narrow band? The Moon's rotation is locked to its orbital period by the tidal forces exerted upon it by the Earth. These tidal forces deform the moon so that it bulges directly towards (and dirctly away) from the Earth. If the moon were rotating at a different rate from the orbital period these bulges would rotate too. Since the bulge has mass, and would rotate out of the line connecting the center of the Earth with the Center of the moon there would be a very slight tug exerted on the Lunar bulge by the Earth which would tend to change the Moon's rotational velocity to be closer to the rate at which it revolves. This same effect is slowing down the rotation of the Earth and driving the Moon into higher and higher orbits. Very slowly of course. Venus must also experience tidal forces with the Sun and perhaps the it is the Sun's tides which have given Venus such a slow rotational period. But the story is more complex. Venus' rotational period is 243 Earth-days which is _longer_ than its 255 day period of revolution. Thus Venus' rotation is retrograde. There is circumstatial evidence indicating that Venus is tidaly locked with the _Earth_. I turns out that when both planets are on the same side of the sun, Venus presents approximately the same face towards the Earth. So it is possible that the Earth's meager (at that distance) gravity is in some way responsible for the small Retrograde rotation of Venus. Another interesting result of tidal effects is the vulcanism of IO. IO is the innermost moon of Jupiter, which would certainly be tidally locked to the planet if it were not for the influence of the nearby moons of Ganymede and Europa. These moons tug on IO and force it to continue rotating even against Jupiter's tremendous tides. This means that the tidal bulge of IO is continually dragged around causing IO to be alternately stretched and pulled. This causes frictional heating which has melted the interior of the moon and causes it to spew forth its innards in copious volcanic flows. -- +-Robert C. Martin-----+---------------------------------------------+ | rmartin@clear.com | My opinions are mine. They aren't anybody | | uunet!clrcom!rmartin | elses. And thats the way I want to keep it.| +----------------------+---------------------------------------------+ ------------------------------ Return-path: X-Andrew-Authenticated-as: 0;andrew.cmu.edu;Network-Mail Date: 10 Nov 90 18:51:40 GMT From: sumax!polari!crad@beaver.cs.washington.edu (Charles Radley) Organization: Seattle Online Public Unix (206) 328-4944 Subject: Re: LLNL Astronaut Delivery (was Re: You Can't Expect a Space Station) References: <2669@polari.UUCP>, <1990Nov7.175448.17819@zoo.toronto.edu>, <1224@iceman.jcu.oz> Sender: space-request@andrew.cmu.edu To: space@andrew.cmu.edu Why not tell the aboriginies and the greens about this:- Most launch sites are wildlife sanctuaries. For example, Kennedy Space Center, Cape Canaveral Air Force Station, and Vandenburg Air Force Base, all of which I know well first hand. KSC is crawling with alligators, manatess, and birds of infinite variety. When working at KSC for Galileo preps there was a Shuttle launch, and I watched the tourists line up in their thousands on the causeway. Little did they know, a couple of hundred metres behind them was a waterway where I used to see a pair of alligators have their morning swim on my daily commute. (They have crocodiles in Queensland don't they ?) In all those locations the wildlife is protected from the development going on outside. Those launch sites all border on prime real estate, which property develpers are overbuilding as fast as they can. Queensland is rather more remote, but with a booming tourist industry, is slowly becoming more developed, and a launch site there would protect the local ecology. Launch sites, for safety reasons, tend to prefer large open space where rockets can explode and stages can drop, and propellant can leak, without hurting people or property. At Vandenburg a week ago I saw a heard of wild deer next to the flight line, and a single Roe deer in the middle of the industrial area. There is also a small pride of mountain lions in a canyon behind the Atlas pads on the south base. ------------------------------ Date: 11 Nov 90 08:48:10 GMT From: sdd.hp.com!think.com!mintaka!ogicse!milton!brettvs%blake.u.washington.edu@decwrl.dec.com (Brett Vansteenwyk) Subject: New Shuttle Engines Not long ago it was noted that the first of Endeavour's engines had arrived at KSC. Some mention was made that these engines were "new and improved". I was hoping that more would be said to elaborate on this, but I will go ahead and pound out a few questions... [1].Are these new engines useable in the older shuttles? It would seem important considering the considerable swapping of engines and their parts that seems to go on in the refurbishment process. [2].Are these engines part of a more "mature" system? In other words, has there been a batch of changes made to the manufacture/design of these "new" engines that will improve their servicability and ease of refurbishment? [3].(Slight rehash from [2]). While the SSME's have not been a particular saftety problem (in hindsight, at least relative to the SRB's), their turn- around launch to launch has been a nightmare for costs--so much of each engine needs to be rebuilt. This seems to stem from the fact that this design pushed the envelope for efficiency and thrust to weight ratio. This engine has been in use for almost 10 years, and it would seem that it could be classified as a "mature" system by now--a learning curve with subsequent reduction in refurbishment costs as well as a more reliable engine. Is there evidence to indicate that this has happened? If not so far, will these new engines allow hope for that to happen in the future? [4].Whenever I see any discussion about new launcher development, I never, or almost never see any suggestion to using the SSME's, nor do I see any indication of an engine derived from SSME technology. The tendency is to discuss systems originating 25 or even 30 years back. I am assuming that the SSME was the most recent major engine development. Has all the time and talent spent to make the SSME work been wasted on what is now considered an evolutionary dead-end? While it may seem disconcerting, it seems where the evidence is pointing. [5].If not the evolutionary dead-end as postulated in [4], could there be an SSME derivative for an expendable launcher, or a restartable version for purposes similar to the Saturn 3rd stage system? (All in all, is it meaningful to think of derivatives of this technology since this is the newest technology by far?) Just some random thoughts. --Brett Van Steenwyk ------------------------------ Return-path: X-Andrew-Authenticated-as: 0;andrew.cmu.edu;Network-Mail Date: 11 Nov 90 21:53:19 GMT From: eru!hagbard!sunic!news.funet.fi!funic!santra!hila.hut.fi!kwiik@bloom-beacon.mit.edu (Kaj Wiik) Organization: Helsinki University of Technology, FINLAND Subject: RadioM1/Rudak2 References: <367@ka2qhd.UUCP> Sender: space-request@andrew.cmu.edu To: space@andrew.cmu.edu SB AMSAT @ ALL < RK3KP $03B004RK3KP RadioM1/Rudak2 R:901103/0935z @RK3KP [NORD>