roberts@CMR.NCSL.NIST.GOV (John Roberts) (03/09/91)
>From: clj@ksr.com (Chris Jones) >Newsgroups: sci.space.shuttle >Subject: Re: Fuel-line door questions... >Date: 8 Mar 91 12:47:29 GMT >Organization: Kendall Square Research Corp >Given the shuttle processing facilities at the Cape, given the parts >cannabilization that goes on to fly one shuttle at a time, >Chris Jones clj@ksr.com {world,uunet,harvard}!ksr!clj I don't think it's nearly as bad as it was before Challenger - then, they *couldn't* have had two orbiters up at once. One of the results of the analysis following Challenger was a massive effort to increase the parts inventory. Of course, there can still be problems when an entire lot is found to have problems, like the fuel line interfaces last summer. Remember, there was a point at which there were two fully assembled Shuttle stacks on transporters, so aside from perhaps a few of the defective parts, it looks as though they had at least two full sets of everything. John Roberts roberts@cmr.ncsl.nist.gov
mvk@aix01.aix.rpi.edu (Michael V. Kent) (03/10/91)
In article <9103090210.AA04529@cmr.ncsl.nist.gov> roberts@CMR.NCSL.NIST.GOV (John Roberts) writes: >I don't think it's nearly as bad as it was before Challenger - then, they >*couldn't* have had two orbiters up at once. One of the results of the analysis >following Challenger was a massive effort to increase the parts inventory. > >Of course, there can still be problems when an entire lot is found to have >problems, like the fuel line interfaces last summer. Remember, there was a >point at which there were two fully assembled Shuttle stacks on transporters, >so aside from perhaps a few of the defective parts, it looks as though they >had at least two full sets of everything. > John Roberts > roberts@cmr.ncsl.nist.gov The reason we don't have two oribiters up at once has nothing to do with orbiter parts. It would take several weeks to swith a part from one orbiter to another (depending on the part of course). Even before 51-L, NASA on two occaisons launched an orbiter within ten days of the previous one landing. Discovery (STS-51D) came down on 19 April 1985 and Challenger was launched on 29 April 1985 on STS-51B. Columbia (STS-61C) landed on 18 January 1986 while Challenger (STS-51L) was launched on 28 January 1986. I can't say for sure, but I doubt there was a lot of parts swapping between them, and if need be I bet they could have launched Challenger on a rescue mission. There is a glitch, however, that will mean no concurrent shuttle flights for the foreseeable future. That is, NASA doesn't have the control facilities or personnel to have two shuttles in orbit at the same time. Considering how NASA is trying to eliminate single-system schedule slips, I would expect that this would change in the future, but I know of no definite plans. Michael Kent mvk@itsgw.rpi.edu
ptc@b15.ingr.com (Paul Carter) (03/12/91)
In <P00-1F#@rpi.edu> mvk@aix01.aix.rpi.edu (Michael V. Kent) writes: >Discovery (STS-51D) came down on 19 April 1985 and Challenger was launched on >29 April 1985 on STS-51B. Columbia (STS-61C) landed on 18 January 1986 while >Challenger (STS-51L) was launched on 28 January 1986. I can't say for sure, >but I doubt there was a lot of parts swapping between them, and if need be >I bet they could have launched Challenger on a rescue mission. Imagine the state of the Shuttle program if Challenger had been sent on a rescue mission....Bingo...two orbiters gone. One stuck in orbit, and one at the bottom of the Atlantic. That would have been a tough pill to swallow. Paul -- +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Paul Carter Intergraph Corporation- Huntsville Ala. uucp: uunet!ingr!b15!ptc (205) 730-6859 ++++++++++++++++++++++++(=o=)+++++++++++++++++++++++++++++++++++++++++
clj@ksr.com (Chris Jones) (03/12/91)
In article <P00-1F#@rpi.edu>, mvk@aix01 (Michael V. Kent) writes: > >Discovery (STS-51D) came down on 19 April 1985 and Challenger was launched on >29 April 1985 on STS-51B. Columbia (STS-61C) landed on 18 January 1986 while >Challenger (STS-51L) was launched on 28 January 1986. I can't say for sure, >but I doubt there was a lot of parts swapping between them, and if need be >I bet they could have launched Challenger on a rescue mission. As I said in my original post, the reason that two shuttles are ready to go at once is that one of them has been delayed. You just can't count on it. (Take a look at the mission designations you just gave.) The current discussion started concerning what would happen if Discovery got stranded if its fuel line doors didn't close. NASA would be foolhardy to launch one of the two shuttles with worse fuel line door problems after a failure in the one with the most minor problem. For a rescue capability to be taken seriously, you have to demonstrate the ability to launch quickly enough to make a difference. The shuttle hasn't done that. The Soviets have, and, in fact, have a group of cosmonauts on call should the need arise to rescue cosmonauts from Mir. There is every reason to believe that the Soviets could wheel out a Soyuz and get it in orbit in a day or three. I don't know if even they have the capability to effect a rescue if the problem arises following separation from Mir--the Soyuz lifetime is then probably two days at most. -- Chris Jones clj@ksr.com {world,uunet,harvard}!ksr!clj
pstinson@pbs.org (03/13/91)
In article <1991Mar11.200153.7206@b15.ingr.com>, ptc@b15.ingr.com (Paul Carter) writes: > In <P00-1F#@rpi.edu> mvk@aix01.aix.rpi.edu (Michael V. Kent) writes: > > >>Discovery (STS-51D) came down on 19 April 1985 and Challenger was launched on >>29 April 1985 on STS-51B. Columbia (STS-61C) landed on 18 January 1986 while >>Challenger (STS-51L) was launched on 28 January 1986. I can't say for sure, >>but I doubt there was a lot of parts swapping between them, and if need be >>I bet they could have launched Challenger on a rescue mission. > > Imagine the state of the Shuttle program if Challenger had been sent on > a rescue mission....Bingo...two orbiters gone. One stuck in orbit, and one > at the bottom of the Atlantic. That would have been a tough pill to swallow. > While we are speaking hypothetically, remember that if CHALLENGER had launched on the 27th, before the deep freeze, it probably would have made it into orbit. The only reason it didn't go the day before was because of a freak problem with closing the hatch. The darned tool wouldn't come off, but if it had, there would have been no bitter pill at all to swallow.
mvk@itsgw.rpi.edu (Michael V. Kent) (03/13/91)
In article <2607@ksr.com> clj@ksr.com (Chris Jones) writes: >As I said in my original post, the reason that two shuttles are ready to go at >once is that one of them has been delayed. You just can't count on it. (Take >a look at the mission designations you just gave.) The current discussion >started concerning what would happen if Discovery got stranded if its fuel line >doors didn't close. NASA would be foolhardy to launch one of the two shuttles >with worse fuel line door problems after a failure in the one with the most >minor problem. I don't deny that the reason these missions were launched in quick succesion was that there was a problem somewhere in the pipeline. My response was to a comment that NASA COULD NOT launch two missions simultaneously because there aren't enough parts to go around. I think a rescue mission would be feasible if a second control station were added and NASA knew what the problem was with the first mission. Although there is a lot of parts swapping between orbiters, it is not to the extent that NASA could not for that reason have two concurrent Shuttle flights. Michael Kent mvk@itsgw.rpi.edu
suitti@ima.isc.com (Stephen Uitti) (03/19/91)
In article <1991Mar12.141225.12004@pbs.org> pstinson@pbs.org writes: > While we are speaking hypothetically, remember that if CHALLENGER > had launched on the 27th, before the deep freeze, it probably > would have made it into orbit. The only reason it didn't go the > day before was because of a freak problem with closing the hatch. > The darned tool wouldn't come off, but if it had, there would > have been no bitter pill at all to swallow. Perhaps not for that flight. Would there have been enough time to notice & correct this failure mode before there was a disaster? I'd like to think so, but I remain skeptical. Stephen.