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Space Forum / Shuttle / December 2007Tanking test?
Its all gone quiet, is it tomorrow, does anyone know? Brian  SignatureBrian Gaff....Note, this account does not accept Bcc: email. graphics are great, but the blind can't hear them Email: briang1@blueyonder.co.uk ______________________________________________________________________________________________________________ > �Its all gone quiet, is it tomorrow, does anyone know? > [quoted text clipped - 5 lines] > Email: bria...@blueyonder.co.uk > ___________________________________________________________________________�___________________________________ last I heard they believe its the connector between the inside and outside of the tank thats causing the troubles...... bet they will try to fly as is. replacing that connector......... are there good spares and how long would it take? >last I heard they believe its the connector between the inside and >outside of the tank thats causing the troubles...... >bet they will try to fly as is. replacing that connector......... are >there good spares and how long would it take? IIUC, replacement would entail at least a 2 to 3 month delay. > IIUC, replacement would entail at least a 2 to 3 month delay. Will they just nudge the pins so they have more tension against the walls of the female connector ? Or will they simply argue that once at altitude, any frozen air will sublimate or whatever and thus make the connectors reliable again ? Under normal circumstances, how long between the time the sensors would detect lack of fuel and actual engine starvation/explosion ? Would it be milliseconds, half a second ? A couple of seconds ? 20 seconds ? Could they adjust software such that: -allows takeoff with "empty" tank. -From the time the tank is computed to be (say) 20% full, the sensors are constantly monitored. If during flight, sensors become functional, then normal ECO logic applies: engines allowed to run until ECO sensors detect no more fuel (or Shuttle has reached its delta-V, whichever comes first). If during flight, sensors do NOT return to functional, then software will shutdown engines based on computed fuel consumption with a large safety margin. Or could it be as simple as adding some heating blanket around those connectors ? Just put an extension cord to power them from the pad and let it all be blasted out during launch. >>�Its all gone quiet, is it tomorrow, does anyone know? >> [quoted text clipped - 11 lines] > bet they will try to fly as is. replacing that connector......... are > there good spares and how long would it take? If they "fly as is" it will be because they have every reason to believe they now understand the problem and consider it safe to fly. > hall...@aol.com wrote: > [quoted text clipped - 18 lines] > > - Show quoted text - yeah like o ring erosion and foam loss........ I thought they said they now understood these connector problems and thought they had fixed them. Seems they were not as successful as they thought, then. Presumably these have the difficulty of having to insulate and provide a barrier to the fuel, while connecting to the circuit inside and the wiring outside. Its an obvious weak link given the different expansion and contraction amounts of the materials used. Makes me a a little twitchy as if there are intermittencies, its a jolly good job the currents are so low, or one spark and its goodbye. It will obviously depend on the point of the problem. If its connector wiring interface,and on the outside, then they have a fighting chance of fixing it, but if its on the 'wet' side it is going to be a pig. The problem is with such low current flows in the system, a tiny bit of corrosion will make a bg difference. Maybe they need to short out the sensor while dry, run a fixed high current through the wiring to get rid of connection resistance, then remove the short, reconnect and fill before it corrodes again. OK, so I realise that in some situations the dis-similar material could create worse corrosion by doing this, so it real depends on what sort of materials are there. Brian SignatureBrian Gaff - briang1@blueyonder.co.uk Note:- In order to reduce spam, any email without 'Brian Gaff' in the display name may be lost. Blind user, so no pictures please! On Dec 17, 4:09?am, "Brian Gaff" <Bria...@blueyonder.co.uk> wrote: > ?Its all gone quiet, is it tomorrow, does anyone know? > [quoted text clipped - 5 lines] > Email: bria...@blueyonder.co.uk > ___________________________________________________________________________?___________________________________ last I heard they believe its the connector between the inside and outside of the tank thats causing the troubles...... bet they will try to fly as is. replacing that connector......... are there good spares and how long would it take? I must improve my touchy typong. !!! Brian SignatureBrian Gaff - briang1@blueyonder.co.uk Note:- In order to reduce spam, any email without 'Brian Gaff' in the display name may be lost. Blind user, so no pictures please! >I thought they said they now understood these connector problems and >thought they had fixed them. Seems they were not as successful as they [quoted text clipped - 42 lines] > bet they will try to fly as is. replacing that connector......... are > there good spares and how long would it take? >I thought they said they now understood these connector problems and >thought they had fixed them. Seems they were not as successful as they [quoted text clipped - 8 lines] > intermittencies, its a jolly good job the currents are so low, or one > spark and its goodbye. Only if the connector is actually leaking H2 on the atmospheric side of the feedthrough. Otherwise, I don't see how a spark could do anything in a pure LH2 environment. > It will obviously depend on the point of the problem. If its connector > wiring interface,and on the outside, then they have a fighting chance of > fixing it, but if its on the 'wet' side it is going to be a pig. > > The problem is with such low current flows in the system, a tiny bit of > corrosion will make a bg difference. I don't see how corrosion could cause this problem. The sensors worked fine at room temperature and failed during the tanking test. The LH2 side of the feedthrough connector gets really, really cold when the tank is filled. Jeff SignatureA clever person solves a problem. A wise person avoids it. -- Einstein On Dec 19, 9:50�am, "Jeff Findley" <jeff.find...@ugs.nojunk.com> wrote: > >I thought they said they now understood these connector problems and > >thought they had fixed them. Seems they were not as successful as they [quoted text clipped - 28 lines] > A clever person solves a problem. > A wise person avoids it. -- Einstein connector is confirmed problem........ |
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