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 ; Fri, 13 Jul 1990 02:04:32 -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, 13 Jul 1990 02:04:01 -0400 (EDT) Subject: SPACE Digest V12 #58 SPACE Digest Volume 12 : Issue 58 Today's Topics: Re: Free Space Station - Spacious but needs work Re: Bush Approves Cape York BRIGHT TIDINGS FOR THE FUTURE Re: Free Space Station - spacious but needs work Re: NASA's lobbying on the net Re: Big Rock Watch Galileo Update - 07/12/90 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: 12 Jul 90 13:28:16 GMT From: eagle!news@ucbvax.Berkeley.EDU (Dave McKissock) Subject: Re: Free Space Station - Spacious but needs work In <9873@pt.cs.cmu.edu>, vac@sam.cs.cmu.edu (Vincent Cate) writes: >Todays New York Times had an article about how the maintenance >for the space station was going to be much higher than even the >recent higher estimate. There is so much work to do that the >current design is out of the question. The maintenance problems >seem to be due to micrometeors, the extreme high/low temperatures, >and radiation in general. Mr. Cate needs to go back and re-read the article in the Times. Mr. Broad reported in the article that "In the 30-year history of the American space program, astronauts have logged a total of 400 hours in space walks, which are considered dangerous BECAUSE OF RADIATION RISKS AND POSSIBLE INJURY OR DEATH FROM SPEEDING DEBRIS AND MICROMETORITES." (Emphasis added by me). The article is saying the problem with radiation & micrometeoroid / debris is that it presents a danger to the astronaut performing EVA to replace a failed Orbital Replacement Unit on Freedom. The majority of the article is discussing the problem of Freedom maintenance. The fundamental problem is that estimates of EVA time to replace failed ORUs is quite a bit larger than allocation for EVA time. The Times article says NASA allocated 130 hours each year to EVA. I don't know the source of that number, recent NASA allocations were one EVA per week (so 52 per year), with each EVA involving two crew members providing a nominal six hours of productive EVA time per crew member. So 52 x 6 x 2 = 624 hours per year. The Times article says Fisher-Price team prior estimates were 2,200 hours of maintenance, and the final report (due next week) has 3,800 hours. Since the article says "NASA will have no official comment on the report" until it is released, I guess I'm not supposed to comment on the report at this time. >The idea of using the external tank as a space station platform >has been around for a long time (I first heard it at a talk at NASA >Ames about 9 years ago). Does anyone know why this idea (which seems >so fantastic) has not been incorporated into the station design? I also recall this idea being tossed around during Phase B of the program. One bad thing about the idea is the problem of refurbishing the tanks to be habitable on-orbit. This would talke alot of, guess what, EVA TIME, which we are having a problem with in the first place. I'm doing a little bit of apples/oranges mixing here. The EVA times mentioned above (624 hrs per year allocated) are for the assembly complete configuration (i.e. after finisning the assembly of the Station, NASA allocates 624 hours per year to maintain the thing). NASA is still in the process of addressing EVA time during the assembly of Freedom. During assembly, there are two kinds of EVA: Shuttle based EVA & Station based EVA. Shuttle based EVA is used to put Freedom together, & change out failed ORUs before Station based EVA is available. The current design of the HAB/LAB modules requires zero EVA time (I believe) for assembly. Just launch 'em in the Shuttle, use the Shuttle arm to hand them off to the Station arm (being built by Henry Spencer's friends up north), & plug them in place. -- ----------------------------------------------------------------------- Dave McKissock sakissoc@csd.lerc.nasa.gov = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = NASA LeRC: Responsible for the remarkable & ingenious Space Station Freedom Electrical Power System = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Opinions expressed herein probably bear absolutely no resemblance to the official NASA position. ----------------------------------------------------------------------- ------------------------------ Date: 12 Jul 90 17:39:47 GMT From: mojo!SYSMGR%KING.ENG.UMD.EDU@mimsy.umd.edu (Doug Mohney) Subject: Re: Bush Approves Cape York In article <987@wyvern.cs.uow.edu.au>, ph@cs.uow.edu.au (Rev Phil Skinque, DD (Ret.)) writes: >>I guess they wouldn't want to put up a com-sat or an observation sat (spy >>sat just doesn't fit the Aussie frame of mind), huh? >Other than that, we can always >acquire elint from our allies the USA (whom you will recall have a >number of satellite bases here). Somehow, I don't think the U.S. would bend over backward to run a KH-11/12 mission in your part of the world unless it was REALLY needed. Most of the coverage is (probably, but Henry will correct me, of course) in the Northern Hemisphere. ------------------------------ Date: 12 Jul 90 15:29:04 GMT From: swrinde!zaphod.mps.ohio-state.edu!rpi!crdgw1!gecrdvm1!gipp@ucsd.edu Subject: BRIGHT TIDINGS FOR THE FUTURE BOY, WHAT A BUNCH OF PESSIMISTS YOU GUYS ARE: HST IS DEAD! NASA IS WASHED UP! SHUTTLE IS TRASH THAT SHOULD BE JUNKED! YOU READ LIKE A BAD SUPERMARKET TABLOID (WHICH I ADMIT HAS ITS ENTERTAINMENT VALUE). MAYBE IT'S JUST MY OPINION, BUT I DON'T THINK ANY OF THE ABOVE ARE TRUE. THEY ALL HAVE FLAWS, YES, BUT DOWN AND OUT, NO. I'LL LEAVE THE HST ALONE, SINCE MANNED SPACE EXPORATION IS MY BAG, AND I WOULDN'T WANT TO BS ABOUT SOMETHING WHICH I AM NOT SOMEWHAT VERSED. NASA: OVERSTAFFED BUREAUCRATS WHO CAN'T BRING ANYTHING IN ON TIME, OR ON BUDGET. EXAGERATED, BUT THERE MAY BE SOME TRUTH TO THIS STATEMENT, BUT THEN, WHAT DO EXPECT FROM A GOVERNMENTAL AGENCY CREATED WITH THE MOTTO 'WASTE ANYTHING BUT TIME' (TO GET US TO THE MOON). THE MAIN STATEMENT IS NOTWHETHER NASA CAN DO SOMETHING, BUT WHETHER THEY CAN DO IT WITHOUT WASTING TONS OF OUR MONEY. WHAT WE NEED, BESIDES A BIG CIVILIAN SPACE AGENCY TO GIVE THEM SOME COMPETITION, IS A NEW FUNDING PROCESS SO THEY DON'T HAVE TO OVERPROMISE IN ORDER TO SELL AN IDEA, SO THEY DON'T HAVE TO HEAP MORE PROMISES ON IN ORDER TO SELL IT AGAIN WHEN A NEW CONGRESS OR ADMINISTRATION ROLLS IN. THE FUNDING PROCESS IS WHAT FORCES THEM TO PROMISE GOLD, WHEN THEY ONLY HAVE LEAD. THE OTHER PROBLEM, RELATED TO THIS PR OVERSELL, IS US, THE CITIZENS OF THE USA (OR AT LEAST THOSE OF US THAT LOOK UP FROM WATCHING BIG TIME WRESTLING LONG ENOUGH TO CHECK OUT THE WORLD). WE DEMAND SPECTACULAR SUCCESSES. DOING SOMETHING IS NOT GOOD ENOUGH FOR US, WE NEED TO DO IT BIGGER, BETTER, ORDERS OF MAGNITUDE ABOVE THE REST. ANYTHING LESS IS FAILURE. THUS NASA, IN ORDER TO LOOK GOOD AND GET OUR APPROVAL AND OUR MONEY (INDIRECTLY, OF COURSE), MUST GO FOR THE BLOCKBUSTER INSTEAD OF INCREMENTALLY ADVANCING (WHICH BY THE WAY, IS HOW THE SOVIETS GOT TO WHERE THEY ARE- SLOW AND STEADY WINS THE RACE). WELL, THE BUBBLE HAS BURST, THE NEWS IS OUT: NASA HAS SOME PROBLEMS! DOES THIS MEAN THEY ARE DEAD? NO!! THEY ARE MERELY (OR SHOULD BE) IN THE SHOP FOR REPAIRS. THERE IS PLENTY OF COMPETITION FOR THEM IN THE WORLD, AND IF THE USA WANTS TO REMAIN COMPETITIVE IN MANNED SPACE (AND OF COURSE WE DO, OUR EGOS WON'T ALLOW ANYTHING ELSE) THEY ARE GOING TO HAVE TO MAKE SOME COURSE ADJUSTMENTS. NOW THAT EVERYONE KNOWS THERE ARE PROBLEMS WE CAN CORRECT THEM (AFTER ALL, HOW DO YOU KNOW YOU HAVE HEMORRHOIDS UNTIL YOU FEEL THE ITCH). NOW, ON TO THE SHUTTLE. A LOT OF PEOPLE APPARENTLY THINK THAT THE SHUTTLE IS JUNK. PERHAPS IT COULD HAVE BEEN BUILT BETTER AND SMARTER, BUT TO SAY IT HAS NO USES IS FOOLISH. I SAY, FINISH UP LAUNCHING THOSE ITEMS CONFIGURED SPECIFI- CALLY FOR THE SHUTTLE AND THEN ELIMINATE IT FOR THAT PURPOSE. IF YOU CAN SHIP SATELITES CHEAPER AND FASTER WITH EXPENDABLES THEN DO SO (BUT FIRST PROVE THAT THIS IS FACT, NOT FANTASY PROMISES). RESERVE THE SHUTTLE FOR MANNED EXPERIMENTATION. THINK OF IT AS A RE-USEABLE SPACE STATION. DO THOSE ADD-ONS THAT WILL KEEP IT UP FOR A MONTH AND USE IT MORE SPARINGLY (DRIVES COSTS UP PER FLIGHT, BUT THEN YOU'RE SAVING MONEY BY LAUNCHING PAYLOADS ON EXPENDABLES). FROM THE LOOKS OF IT, WE'RE NOT GOING TO HAVE FREEDOM OR ANY OTHER SPACE STATION ANYTIME SOON, SO THE SHUTTLE IS ALL YOU'VE GOT. I DON'T THINK YOU CAN DO QUITE THE AMOUNT OF WORK IN A CRAMPED CAPSULE THAT YOU CAN IN SPACELAB. I THINK THE QUESTION NOW IS, WHERE DO WE GO FROM HERE? I BELIEVE EXPENDABLE CAPSULES IS A STEP BACKWARDS, AT LEAST UNTIL YOU GET A STATION UP THERE, AND MAYBE EVEN THEN (BY THE BY, I DON'T THINK LIVERMORE IS GOING TO PUT UP THEIR BLOW-UP STATION TOO QUICKLY EITHER, OR FOR AS CHEAP AS THE 500 MIL FIGURE I HEAR BANDIED AROUND THIS NEWSGROUP). I WOULD RATHER SEE A WHOLE NEW AVENUE TAKEN: AN AIR LAUNCHED MANNED PLANE BIGGER THAN PEGASUS/X-15 (ALONG THE LINES OF SAENGER BY MBB) SERVICING A SMALL EXPANDABLE STATION. OR MAYBE WE CAN KEEP ON BICKERING AND THEN BEG A RIDE ON HERMES OR HOPE. THESE OPINIONS ARE MINE AND DO NOT REPRESENT ANYONE BUT ME. THEY ARE NOT INTENDED TO INSULT ANYONE. PETE ------------------------------ Date: 12 Jul 90 16:23:05 GMT From: news-server.csri.toronto.edu!utgpu!utzoo!henry@rutgers.edu (Henry Spencer) Subject: Re: Free Space Station - spacious but needs work In article <9873@pt.cs.cmu.edu> vac@sam.cs.cmu.edu (Vincent Cate) writes: >If external tanks were used as shells for the space station modules >these problems would be solved. The ET walls must be fairly >thick because the fuel is rather heavy at launch (3 inches thick?). >Thus the ET should do a good job of providing thermal insulation and >protecting against radiation or micrometeors! Nope, sorry, the ET walls are quite thin. They have to be, or the thing would be too heavy to fly. They are thin enough that the folks looking at converting one into an orbiting gamma-ray telescope figure they will need to put some kind of outer "meteor bumper" shield around the ET or it will be punctured fairly quickly by debris. A contributing reason for doing this is that it will keep the ET's sprayed-on insulation *in*; apparently the stuff will "popcorn" in vacuum, worsening the space-debris problem. >While currently the external tank does not go into orbit it would >actually take less fuel if they did put the external tank in orbit. >They currently get to orbital speed and then do an extra maneuver to >send the ET back down... Sorry, not so, not any more. They did that in the early days, but they now use "direct ascent" trajectories that avoid this. There is a cost for getting the ET up. A worse problem, actually, is keeping it up, since it's a big light object and is badly affected by air drag. You have to do something with it quickly. >The idea of using the external tank as a space station platform >has been around for a long time (I first heard it at a talk at NASA >Ames about 9 years ago). Does anyone know why this idea (which seems >so fantastic) has not been incorporated into the station design? Partly because there are real problems with it; see above. Partly because NASA has a phobia of trying to do in-orbit assembly work, and fitting tanks out as a station would take a lot of it. Partly because it carries just a tiny bit of risk, which NASA is averse to nowadays. >PS Maybe if lots of us call NASA and tell them about this idea > (like many votes) they will really think about it. Save your breath; they *have* heard about it, and the "Outreach" program is *not* a popularity poll. -- NFS: all the nice semantics of MSDOS, | Henry Spencer at U of Toronto Zoology and its performance and security too. | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: 13 Jul 90 01:11:10 GMT From: unmvax!nmt.edu!nraoaoc@ucbvax.Berkeley.EDU (Daniel Briggs) Subject: Re: NASA's lobbying on the net In article <9007112052.AA24159@ibmpa.paloalto.ibm.com> szabonj@ibmpa.UUCP (Nicholas J. Szabo) writes: > > Look, I am not trying to be a grinch here, I just want to point out... > [In spite of good intentions, he does a reasonable job of grinching.] In article shafer@skipper.dfrf.nasa.gov (Mary Shafer) writes: > > Fine. That's it, I'm out of here. In article <8700@jpl-devvax.JPL.NASA.GOV> leem@jpl-devvax.JPL.NASA.GOV (Lee Mellinger) writes: > > Although I don't post very often (NASA/JPL work to do you know), I > vote with Mary. It's been nice (sometimes). Whoa, people! Let's not speak too hastily. I'll admit, I have stayed out of this one because I thought if I ignored it, the issue would eventually go away. Obviously, I was wrong. I'd sure hate to see anyone drop the group, just because of one *stupid* issue. First, Nick: Will you please let this issue die? In the interests of group harmony, if for no other reason. While I personally don't agree with you, I'm not going to press my opinions into the fray here. It *isn't* worth the friction that it would cause! Consider that the issue is obvious contentious. You are obviously not going to change the mind of a significant number of NASA personel, yet you may well hurt the feelings of many of them. What good will that accomplish? The fact is, arguing about this issue is not going to change a bloody thing, but will make a lot of people angry and unhappy. Like civilized people, let's just agree to disagree and leave it at that. Second, Mary & Lee & anyone else feeling a bit stepped on: You really *are* wanted here. I'm sorry that more of us with positive feelings towards the NASA crowd didn't speak up sooner. I know that *I* find it very hard to speak about what I do without getting rather worked up. I can't see how anyone could possibly work at a place like NASA and not feel at least somewhat the same. I certainly don't feel like I'm lobbying when I talk enthusiastically about some new telescope or several that we are building. Why should I make that assumption about you? I don't! It's hard to ask someone to stick around, and put up with inevitable and significant bashing of their employer. But know that if you do, it is effort that is greatly appreciated by many of us! Everyone: In a group like sci.space, it is easy to get lost in the rivets and forget that there are *people* on the other side of the postings. It's just as important to remember the other guy when you post here as it is when you post to something like alt.callahans. We just talk about different stuff here. We are all in the group for basically the same reason: love of space. The only real differences between us are that we don't agree how to get there. That shouldn't be a reason for bashing each other, should it? Let's leave the flaming on news.groups, where it belongs, OK? -- This is a shared guest account, please send replies to dbriggs@nrao.edu (Internet) Dan Briggs / NRAO / P.O. Box O / Socorro, NM / 87801 (U.S. Snail) ------------------------------ Date: 12 Jul 90 14:36:25 GMT From: thorin!homer!leech@mcnc.org (Jonathan Leech) Subject: Re: Big Rock Watch In article hart@blackjack.dt.navy.mil (Michael Hart) writes: >>It is going 22,000 mph relative to Earth, and as a WAG (+- 200%) >>masses 13 million tons. Such a collision with Earth would >>release 1.5e17 (150 thousand trillion) calories of energy. >Can anyone give an approximation of what would happen if a rock >this size were to impact the earth, releasing the above mentioned >amount of energy? About a 2.5km diameter crater, if I didn't drop any decimals (ref Shoemaker, Ann. Rev. Earth & Planetary Science 1983, 11:461-94). This one seems to be moving pretty slowly, which would be to our advantage. -- Jon Leech (leech@cs.unc.edu) __@/ "Why do you suppose we only feel compelled to chase the ones who run away?" "Immaturity." _Dangerous Liasons_ ------------------------------ Date: 12 Jul 90 16:48:00 GMT From: swrinde!zaphod.mps.ohio-state.edu!usc!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov!baalke@ucsd.edu (Ron Baalke) Subject: Galileo Update - 07/12/90 GALILEO MISSION STATUS July 12, 1990 The Galileo spacecraft is 87.7 million miles from Earth (round-trip communication time 15 minutes 43 seconds) and 114.6 million miles from the Sun. It has travelled 450 million miles in space since launch last October 18, and its heliocentric speed is now just over 52,000 mph. The flight team has developed and reviewed the design of next week's trajectory correction maneuver. It calls for 228 pulses using the axial thrusters (toward the Sun) and 160 lateral pulses (at nearly a right angle to the Sun-line) for a total velocity change of less than one meter per second (about 2 mph). The command sequence will be sent to the spacecraft next Monday, and the maneuver operation will begin about 11 a.m. (PDT) Tuesday, July 17. Meanwhile, at the spacecraft, things are relatively quiet. Routine science observations of the interplanetary environment continue, with data readouts about every 4-5 days; there are also regular scheduled engineering calibrations and system maintenance activities. Galileo's performance continues to be excellent. ___ _____ ___ /_ /| /____/ \ /_ /| | | | | __ \ /| | | | 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 #58 *******************