Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.3 4.3bsd-beta 6/6/85; site ucbvax.BERKELEY.EDU Path: utzoo!watmath!clyde!burl!ulysses!bellcore!decvax!decwrl!ucbvax!space From: dietz@SLB-DOLL.CSNET (Paul Dietz) Newsgroups: net.space Subject: Re: Scuttle the Shuttle? Message-ID: <8602061514.AA06010@s1-b.arpa> Date: Thu, 6-Feb-86 08:22:51 EST Article-I.D.: s1-b.8602061514.AA06010 Posted: Thu Feb 6 08:22:51 1986 Date-Received: Sun, 9-Feb-86 04:42:55 EST Sender: daemon@ucbvax.BERKELEY.EDU Organization: The ARPA Internet Lines: 107 > But there are a lot of > things that it can do quite well that no current or previous space > transportation system could even aspire to do. Name one that justifies the cost of the shuttle system (vague references to philosophical principles not allowed). And no ranting against bean-counters, either. > The real question is not whether the shuttle is advancing > the exploitation of space (obviously it is) but whether it is doing > so more effectively and economically than the alternatives. I wait > to see your proposed alternatives. It's not obvious to me that the shuttle is advancing the exploitation of space. It's not making the launching of unmanned satellites any cheaper. It's not a cheap enough launcher to make space manufacturing economical. It has been (and is) soaking up money that could be spent on other more worthwhile endeavors: - Development of cheaper launchers - Unmanned probes to look for easily accessible extraterrestrial resources (Earth co-orbital asteroids, lunar polar ice deposits) - Development of space qualified teleoperator systems > As far as I know nobody > has had any success in space operations using "robots and teleoperated > manipulators." .I will put the ball back in your court; you are making a > positive assertion here, that these things can be done. Do you have one > shred of evidence to back this up? Are not ALL the planetary probes robots? And is not the shuttle arm a teleoperator? It doesn't matter that the person controlling it is in the shuttle cabin or on the ground (except for a small speed-of-light delay). NASA is planning an remote controlled orbital maneuvering vehicle for low orbit retrieval tasks and (I think) a remote controlled orbital transfer vehicle. Teleoperated submarines are being used in the oil industry today, and have been used to manipulate radioactive substances for years. The technology drivers for teleoperated systems (sensor technology, electronics, communications) are developing explosively, while the technology driver for manned space presence (cheap launch systems) is developing slowly. > This doesn't really make sense, as I'm sure you're aware. If all the > vehicle is going to do is deploy satellites in earth orbit it makes far > more sense to just launch the satellite and not the whole orbiter. And > the loss rate would be a lot higher than 4% without onboard human control, > if the operation could be managed at all. The shuttle does have one advantage currently: it can launch much larger payloads in one piece than expendable rockets. I doubt, however, that the loss rate would change significantly with no humans on board, given sufficiently sophisticated remote control. Leaving people out might improve the economics of the shuttle (although I'm told the major weight is in the wings and airframe). > Even if it were possible it would mean abandoning: >-- All repair operations in earth orbit > (e.g. Landsat, Solar Max, and many more). >-- All recovery operations in earth orbit > (e.g. the Long Duration Exposure Facility). >-- All servicing operations in earth orbit. > (e.g. inspection and maintenance of Hubble Telescope) >-- All human-directed experimentation and observation in earth orbit. > (e.g. many biology, manufacturing, physics experiments) >-- All experimation and study of humans in earth orbit. > (e.g. studies of human response to weightlessness, human efficiency > in weightlessness) >-- All plans for possible space station construction. Let me address these one at a time: (1) Satellite repair. This is a sparse market (for STS). If satellites are designed properly there's no reason why one couldn't do it with teleoperators (as will have to be done in geosynchronous orbit anyway, where most satellites are). The economics of satellite repair are dubious when the satellite has to be relaunched (as those two comsats with failed boosters will have to be). (2) Recovery operations in earth orbit. LDEF was deployed and will be recovered with the shuttle arm -- a teleoperator! (3) Servicing in earth orbit. There appears to be no good reason why you couldn't service a properly designed space telescope (say) by remote control. I believe a teleoperator with the proper appendages (screw drivers, grippers, refueling attachments, etc.) could be more efficient than a person in a bulky spacesuit. Servicing in geosynchronous orbit will require teleoperators. (4) Human-directed experimentation. I said spacelab had produced some good science. I heard on the news the other night, however, that preparing a science payload for the shuttle is five times (!) more expensive than for an unmanned launcher. And it's seriously debatable whether it's worth the cost. It certainly won't lead to space based manufacturing on any worthwhile scale until launch costs are reduced dramatically. (5) Experimentation and study of humans in orbit. This should be a means to an end, not an end in itself, and if human presence is deemphasized in the near term there's no reason to do this now. (6) Space station construction. Yes, I believe teleoperators COULD do this, and besides, it makes no sense to build a space station until launch costs are reduced to the point that humans make more sense in space. I too believe in the use of space; I want my grandchildren to be born in space. I just think the shuttle is a waste of effort and is not moving us towards worthwhile long term goals in space.