allen@mmm.UUCP (Kurt Allen) (03/19/86)
Why did'nt NASA create a shuttle that would ride on top of expendable boosters ala Hermes/Ariane and the Soviet shuttle (both under development). It seams to me that this probably would have had the following effects 1. Cheaper. NASA could have kept the Saturn production lines open, and used only proven boosters, eliminating the R&D dollars used to develop the shuttle boosters. The earlier work done on Dyna-Soar, which was to have flown on expendable boosters, could have formed the basis of the shuttle. 2. Allowed development of a smaller shuttle, that would not have to do everything the current shuttle does. Large payloads could have been lofted by a Saturn IB or Saturn 5. The development of a smaller shuttle would have been cheaper and safer, utilizing more proven technology. 3. Have speeded up development of the shuttle. That period of time in which the US of A did'nt have any manned space systems because we were waiting for the shuttle would'nt have occured. Skylab might be the nucleas of an permanently manned american space station, rather than a smear across Australia. 4. Have allowed backup systems to the shuttle so that grounding of the shuttle would'nt have caused a hold on the whole american space program. 5. Kept in existance an unmanned system to use for lofting very dangerous payloads. I.E. interplanetary probes carrying large amounts of explosive fuel. Where would we be now if we had made a less advanced shuttle of the above type ?
henry@utzoo.UUCP (Henry Spencer) (03/25/86)
> Why did'nt NASA create a shuttle that would ride on top of expendable > boosters ala Hermes/Ariane and the Soviet shuttle (both under development). Because it does increase operating costs, and low operating costs were a major rationale for the Shuttle. Also, looking at it from another angle, what do you think the external tank and the SRBs are? The tank isn't reusable, the SRBs are reusable only to a very limited extent. Note also that you are comparing paper studies against flying hardware. > It seams to me that this probably would have had the following effects > > 1. Cheaper. NASA could have kept the Saturn production lines open, > and used only proven boosters, eliminating the R&D dollars used to develop > the shuttle boosters... The boosters would still have needed work to make them suitable for launching the shuttle. One cannot change everything above a lower stage without affecting things like vibration modes within that stage. That's why the Saturn V was tested "all up", rather than one stage at a time. NASA wanted rather badly to launch the Shuttle with a (reusable) variant of the Saturn V first stage. But it pushed the costs up just a little higher, and the bean-counters said no. > The earlier work done on Dyna-Soar, which was to have > flown on expendable boosters, could have formed the basis of the shuttle. In many ways, it did. > 2. Allowed development of a smaller shuttle, that would not have to > do everything the current shuttle does. Large payloads could have been lofted > by a Saturn IB or Saturn 5... This part I agree with. > The development of a smaller shuttle would have > been cheaper and safer, utilizing more proven technology. This is not self-evident. With the possible exception of the SSME's, I can't think of anything in the shuttle whose development was greatly sensitive to size. > 3. Have speeded up development of the shuttle. That period of time in > which the US of A did'nt have any manned space systems because we were > waiting for the shuttle would'nt have occured... The shuttle could have been operational several years earlier than it was, if NASA had been willing to settle for something less than perfection. In (I believe) about 1970 Lockheed proposed the "Starclipper", sort of a mini-shuttle using an expendable tank but no external boosters. Estimated development cost (undoubtedly somewhat optimistic) was one billion. It was rejected because it was not fully reusable. > 4. Have allowed backup systems to the shuttle so that grounding of the shuttle > would'nt have caused a hold on the whole american space program. To some extent. Undoubtedly many payloads would still be dependent on the shuttle to some degree. Turn it around, though: if the shuttle were boosted by (say) a Saturn V derivative, also used as a cargo launcher, and a disastrous flaw was found in the expendable parts, we'd be no better off than we are now. Remember that there were 24 successful shuttle flights, and the Saturn V only flew 12.5 times (Skylab wasn't a complete Saturn V), so such a problem could still have been lurking in it. > 5. Kept in existance an unmanned system to use for lofting very dangerous > payloads. I.E. interplanetary probes carrying large amounts of explosive fuel. There is something to be said for this. Although the "large amounts" of explosive fuel in the cargo bay of a Centaur-carrying shuttle are dwarfed by the amounts ten feet away in the external tank. > Where would we be now if we had made a less advanced shuttle of the above > type ? Probably with no manned space program at all, since NASA couldn't have kept it going without USAF support. And keeping the Saturn V in production is a decision that would have had to have been made in about 1967; the time when serious shuttle thinking started was far too late. -- Henry Spencer @ U of Toronto Zoology {allegra,ihnp4,linus,decvax}!utzoo!henry
corwin@hope.UUCP (John Kempf) (03/25/86)
> Why did'nt NASA create a shuttle that would ride on top of expendable > boosters ala Hermes/Ariane and the Soviet shuttle (both under development). > It seams to me that this probably would have had the following effects > > 1. Cheaper. NASA could have kept the Saturn production lines open, > and used only proven boosters, eliminating the R&D dollars used to develop > the shuttle boosters. The earlier work done on Dyna-Soar, which was to have > flown on expendable boosters, could have formed the basis of the shuttle. > ... > > Where would we be now if we had made a less advanced shuttle of the above > type ? *** EAT HOT ELECTRONS LINE EATER SCUM *** In his artical, Mr. Allen makes some very good points. I agree that we should have kept the old systems operational. The point that I strongly disagree with however, is that we should not have done the reasearch necessary to create the shuttle. Shure, it would have been cheaper, and easier, but we would not have advanced any. In effect, we would have wasted those interviening years. Shure, what we had worked fine, but that could be said about almost any form of technology. There is always room for improvement. Spending money on R&D is not a waste. In almost every case, sooner or later, it almost always pays off. -cory