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!ucbvax!space From: dietz@SLB-DOLL.CSNET (Paul Dietz) Newsgroups: net.space Subject: Re: scuttle the shuttle? Message-ID: <8602070221.AA08568@s1-b.arpa> Date: Thu, 6-Feb-86 17:07:47 EST Article-I.D.: s1-b.8602070221.AA08568 Posted: Thu Feb 6 17:07:47 1986 Date-Received: Sun, 9-Feb-86 05:46:16 EST Sender: daemon@ucbvax.BERKELEY.EDU Organization: The ARPA Internet Lines: 129 >Actual cost to a user is more like $1500/lb. Contrary to making space >manufacturing uneconomical, only the shuttle makes space manufacturing >POSSIBLE (except for the now defunct Salyut). NY Times reports $2000 to $2500/lb. Where do your figures come from, and what assumptions are you making (is amortization of the orbiter included, for example, and how large is the payload?). Cost to the *user* is also a little misleading, since it doesn't include the cost NASA incurs to subsidize launching rates. The ability to make things in space is worthless if the product costs more than you can sell it for. > No industry in the history > of the world has been established without people there to set it up. The satellite communications industry works very well even though no person has ever been to geosynchronous orbit. And the history of ground based industries are clearly irrelevant, since life support and transportation are so cheap down here. >The shuttle can put the people and the equipment up >to do all of the the initial, necessary startup work for establishing >orbital factories. No other space system in use today, with the possible >exception of the Soviet system, can do that. At any price. That goes >for any near terms plans that I am aware of as well. You can do microgravity experiments in unmanned satellites (fit them with a heat shield and retrorockets). Indeed, some microgravity work needs a better environment than the shuttle can provide and would have to be done in free flyers. Also, doing research for space manufacturing would be more reasonable if we could expect to have cheaper launcher soon (but we're not going to). > McDonnell Douglas and 3M are both seriously working > on orbital processing. McDonnell Douglas's partner, Ortho Pharmaceuticals, has pulled out of the continuous flow electrophoresis project because it claims it can make the drugs just a cheaply on the ground. My impression of the 3M work was that it was research at this stage, and that NASA has been unable to get 3M to commit to using the space station (please correct me if I'm wrong on this second point). > Almost every flight lately has had some kind of materials > processing experiments, many of which have gone very well. Japan and > Europe are extremely interested in this area. Some reports claim that > a substantial fraction of the all of the semi-conductor material used > by the Soviets come from Salyut. No doubt experiments have gone well (and why not conduct the experiments, when NASA heavily subsidizes them), but that's not the same thing as setting up space manufacturing. Such experiments can be valuable even if you don't intend to do space manufacturing, because they let you identify what effect convection is having on your ground-based process. Rumors about the Soviets are interesting but hardly persuasive. Crystallizing silicon in orbit makes little sense, so you probably have this garbled. > Shuttle, with all of its problems, has a better record than Ariane (an > unmanned European system) for lifting satellites into orbit. Until the > current flight, no shuttle launched satellite had been a complete loss, > although there were several partial failures. Not true. One shuttle launched satellite failed after being injected to its transfer orbit (this wasn't the first TDRS). Ariane has been unreliable, but that happens with any system on its first flights. The later Arianes will have the problems fixed and will (asymptotically) become more reliable. If you criticize Ariane for teething problems you must also, in all fairness, criticize the PAM, IUS and the shuttle itself for reliability problems. > Launching satellites ALWAYS involves a lot of vibration. With the shuttle, > however, you have people on board to fix problems that come up and the > payload can be returned to Earth for repair and reflight as well. Try that > on an expendable booster. But much more vibration when you use monster solid rockets. The record of people on the shuttle fixing external experiments in the cargo bay has not been exceptional. > Shuttle initiated satellite repair on orbit, satellite retrieval, and has > given a lot of people hands on experience with the problems of working in > space. Construction techniques have been verified by actual experiment. > With the return of the long duration exposure facility we will get a good > look at the long term effects of low earth orbit on many materials. Something > we can only get if we RETURN things from space, which only the shuttle can > do. All of these substantially further real exploitation of space. In > addition, shuttle capabilities are critical to space station, and various > commercial projects to establish industry in space. Of course material can be returned to earth without the shuttle: simple ablatively cooled capsules (both manned and unmanned) have been used for years. The utility of people doing EVAs in low orbit is debatable; the expertise does not easily extend to where it would be more useful (geosynchronous orbit). I don't believe space manufacturing is currently economically viable, so I don't buy the space station argument. About teleoperation: because people are adaptable, they can do things (like doing unanticipated repairs on satellites) that would be hard for a machine to accomplish. However, the important question is: is the extra adaptability humans possess worth the considerably higher costs incurred in putting them in space? If teleoperators can accomplish 90% (say) of the things people can do, people should probably stay on the ground for a while. The need for adaptability can be reduced by proper design. For example, a communications satellite can be designed in a modular fashion so that spare parts may be plugged in with little dexterity. This is analagous to redesigning a product so that robots may put it together easily rather than build extremely capable robots that can mimic human assembly techniques. There has been considerable work in teleoperated manipulators on remote controlled submersible vehicles, motivated by their applications in off-shore drilling and in the military. The latest issue of High Technology (Feb. 1986) has an interesting article on the technology. > Here in the Bay area they though human pilots were unnecessary for the > extremely simple problem of controlling subway cars. They were wrong, the > automatic systems on BART have been the source of never ending problems. > People are very good at controlling vehicles, we should use them. The time critical parts of a shuttle flight are already computer controlled (lift-off and landing). The in-orbit part can be handled simply by sending shuttle telemetry to (say) a ground based cabin mockup. You'd need the TDRS satellites in orbit for this to work.