Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!samsung!noose.ecn.purdue.edu!mentor.cc.purdue.edu!mace.cc.purdue.edu!dil From: dil@mace.cc.purdue.edu (Perry G Ramsey) Newsgroups: sci.space.shuttle Subject: Re: launch ratesDOWN 18 Summary: Sure, Saturn was grossly inefficient. Why is the Shuttle worse? Message-ID: <5640@mace.cc.purdue.edu> Date: 28 Sep 90 16:35:55 GMT References: <10195.26fde341@pbs.org> <1990Sep25.033816.16652@zoo.toronto.edu> <10230.27023455@pbs.org> Organization: Department of Earth and Atmospheric Sciences Lines: 61 In article <10230.27023455@pbs.org>, pstinson@pbs.org writes: > In article <1990Sep26.174811.8026@zoo.toronto.edu>, henry@zoo.toronto.edu (Henry Spencer) writes: > > > The Saturn had reached a launch rate that the > > shuttle is struggling, so far mostly unsuccessfully, to beat. > > -- > [1992 is] International Space Year. > Let's just wait in see what the Shuttle is doing > by the end of 1992. 20 years after the Shuttle design was selected. >I expect we will see at least 9 launches in 1991 and at > least 12 more in 1992. No year after that will see less than 10. That's what they they said in 1985 about 1986. > By the way. How long do you think the U.S. Congress would have let NASA go on > building from scratch 5 Saturn V's a year simply to be discard them after one > launch? The rate from late 1968 through late 1969 was unsustainable. And that is the real irony of this whole situation. Expendibles are clearly inefficient. It's just that the Shuttle is worse. As I see it, the current NASA couldn't launch Saturns, either. The kind of operational paralysis which currently grounds the Shuttle (a vehicle which should be relatively easy to launch) would be even worse with a large, complex expendible. They can't currently get the two major liquid propulsion system with five engines to work right; the Apollo/LM/Saturn had six major systems with 14 engines. Shuttle Propulsion systems: Main: 3 Hydrogen OMS: 2 hypergolic Saturn SIC: 5 RP-1 SII: 5 hydrogen SIVB: 1 hydrogen LM Descent: 1 hypergolic LM Ascent: 1 hypergolic CSM: 1 hypergolic I don't include the solids, because solids are so simple that they can't fail, and don't warrant comparison in complexity to the main propulsion system (I'd put a smiley here if I could smile about it.) If you insist on throwing them in, that's one and a half more systems and two more engines. In any case, that's half the number of systems and engines. I don't want to get into the mode of mindless Shuttle bashing here, (I'm actually an ex-Shuttle engineer), but there is no doubt that we have a seriously flawed system here, and it needs to be fixed. Getting starry-eyed about "Space ... the final frontier" and ignoring the Shuttle's problems isn't going to help make it better. -- Perry G. Ramsey Department of Earth and Atmospheric Sciences perryr@vm.cc.purdue.edu Purdue University, W. Lafayette, IN USA dil@mace.cc.purdue.edu We've looked at clouds from ten sides now, And we REALLY don't know clouds, at all.