Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!ucselx!crash!pro-canaveral.cts.com!gandalf From: gandalf@pro-canaveral.cts.com (Ken Hollis) Newsgroups: sci.space.shuttle Subject: Re: LH2 Leak... Message-ID: <5760@crash.cts.com> Date: 20 Nov 90 23:16:16 GMT Sender: root@crash.cts.com Lines: 100 Greetings and Salutations: >From: Wales.Larrison@ofa123.fidonet.org (Wales Larrison) >Subject: Re: Causes for Columbia leaks ?? > The scuttlebutt in the industry was that the Columbia problems >were caused by the new MLP used, and some mis-judgements and >untrained technicans. Now this is "third bar seat on the left" >unoffical rumor data, but I've heard it from a couple of sources. > The Mobile Launch Platform (MLP) used for the initial tanking >test was a new one - and the cleaning procedures used on the cryo >lines through the MLP through the aft end of the orbiter and into ET Note: The MLP lines and/or the ET had the corundum, not the MPS lines. The most likeley source is the MLP GSE (Ground Support Equipment) lines. >weren't really up to snuff. When they did the first tanking test, ...If you wanna call "launch" a tanking test, then so be it... >they found cleaning material grit in the fuel system filters (used to >clean the MLP cryo lines before use...) - and since that is very After the launch & after the corundum was found in the MPS lines... >highly abrasive, and not something you want to run through high >speed turbopumps, and shouldn't have been there in the first place - The corundum was found in the OPF (Orbiter Processing Facility) upon returning from landing (Reference LDEF retrieval). >they decided to dissamble and clean out the MPS (Main Propulsion >System) feedlines in the aft end of the orbiter. > The MPS system is pretty complex, since the systems are very >complex physically, pretty sizable (each line is about 24" across), 17" across (Internal diameter) >and are vacuum jacketed and foamed. There are about 83 pieces which >have to be fitted back together and tested. Disassembly and 83 major components (depending on how you count major). Hundreds of joints alone were leak checked. >reassembly has been done several times - each system is assembled >and tested at the Rockwell manufacturing plant in Palmdale, Assembled for acceptance testing by NASA, and most of the tech's at Palmdale have less experience than the tech's at KSC. >California when each shuttle is built, and at the Arrowhead Products >plant in Southern California, when they make the parts before >shipping them to Rockwell Palmdale. Nobody knew of one being >stripped and reassembled at KSC. It's not thier problem when it is at KSC. They don't have control over it anymore. > The rumor goes that Rockwell Palmdale and Arrowhead Products >quickly put together a team to go down to KSC and perform the work Sure, "At a price..." >needed - figuring the most experienced team would do the job the All of the tech's at KSC were hired from Rockwell when LSOC (Lockheed Space Operations) got the contract. Alot of them worked on STS-1. >quickest and best. However, NASA KSC and Lockheed, the Shuttle >operations contractor to NASA KSC, have been pushing for more >maintenance work to be done at KSC. (They figure after the >Endeavour is built, all of the Rockwell technicans will be out of a >job, so they'll have to fix it themselves...) So they decided that All of the regular maintenance and testing and testing is done at KSC. It is rare when Rockwell actually does work on the bird. >Lockheed shuttle techs would strip down, clean, and reassemble the >MPS at KSC. > However, in putting the system back together, several teflon >seals were "crushed", which allowed the leaks. This required The "Crushed Teflon Seals" were installed by a Rockwell subcontractor, not by Lockheed. >dissasembling and retesting the system, yet again. > To their credit, the Lockheed techs did manage to get it put >back together the right way, and the tested leak rate is the lowest >of any shuttle. > > Remember - this is rumor - and unconfirmed by any published >reports. > >Wales Larrison Ken Hollis ProLine: gandalf@pro-canaveral Internet: gandalf@pro-canaveral.cts.com UUCP: crash!pro-canaveral!gandalf