andy@syma.sussex.ac.uk (Andy Clews) (11/02/90)
Three hypothetical scenarios (and I hope they remain so): Suppose, for some reason, the payload bay doors fail to close under their own mechanism whilst the orbiter is in orbit. Does a mechanism exist for members of the crew to attempt to close the doors manually? Suppose also, that the doors close but cannot be locked for some reason (as I assume they are in the normal course of events). Would this be a fatal mishap, i.e. would it prevent the orbiter from attempting a re-entry and landing? On a related note, suppose the payload bay doors cannot be _opened_ once the vehicle is in orbit. Would this pose serious problems, given that the door-mounted radiators would be unable to vent excess heat into space? A lighter note. I have just completed a 1/72 scale model of Columbia (the Revell one). The payload bay doors do not close properly. I have instigated an inquiry into why this is so, how it can be corrected and how to prevent it happening again. My Mum and my Uncle Norman are on the board of enquiry. ;-) -- Andy Clews, Computing Service, Univ. of Sussex, Brighton BN1 9QN, England JANET: andy@syma.sussex.ac.uk BITNET: andy%syma.sussex.ac.uk@uk.ac
henry@zoo.toronto.edu (Henry Spencer) (11/03/90)
In article <3731@syma.sussex.ac.uk> andy@syma.sussex.ac.uk (Andy Clews) writes: >Suppose, for some reason, the payload bay doors fail to close under their >own mechanism whilst the orbiter is in orbit. Does a mechanism exist for >members of the crew to attempt to close the doors manually? Yes, although I believe it requires an EVA. >Suppose also, that the doors close but cannot be locked for some reason (as >I assume they are in the normal course of events). Would this be a fatal >mishap, i.e. would it prevent the orbiter from attempting a re-entry and >landing? One would want to have them reasonably secure. It's hard to see what sort of failure would make all the latches fail, especially since I *think* there is a manual latching procedure. A few malfunctioning latches should not be harmful. >On a related note, suppose the payload bay doors cannot be _opened_ once the >vehicle is in orbit. Would this pose serious problems, given that the >door-mounted radiators would be unable to vent excess heat into space? It would mean a mission abort and a prompt reentry. There is enough time before serious problems occur to permit this. -- "I don't *want* to be normal!" | Henry Spencer at U of Toronto Zoology "Not to worry." | henry@zoo.toronto.edu utzoo!henry
jabishop@uokmax.ecn.uoknor.edu (Jonathan A Bishop) (11/04/90)
henry@zoo.toronto.edu (Henry Spencer) writes: >In article <3731@syma.sussex.ac.uk> andy@syma.sussex.ac.uk (Andy Clews) writes: >>Suppose, for some reason, the payload bay doors fail to close under their >>own mechanism whilst the orbiter is in orbit. Does a mechanism exist for >>members of the crew to attempt to close the doors manually? >Yes, although I believe it requires an EVA. >>On a related note, suppose the payload bay doors cannot be _opened_ once the >>vehicle is in orbit. Would this pose serious problems, given that the >>door-mounted radiators would be unable to vent excess heat into space? >It would mean a mission abort and a prompt reentry. There is enough time >before serious problems occur to permit this. Could they not also EVA at this point? I recall seeing a piece on this during the pre-launch coverage of STS-1. I don't know if the information was accurate or not, but the piece stated that, in the event that the doors did not open, Crippen would EVA to the rear of the cargo bay (semantics point: is it an EVA if you have to wear a space suit but you're still inside your vehicle?), where the manual crank was located. They showed him practicing the procedure in the neutral buoyancy tank. -- jabishop@uokmax.ecn.uoknor.edu "Ground Control to Major Tom: Your circuit's dead; there's something wrong. Can you hear me, Major Tom?" -- David Bowie
demers@SRC.Honeywell.COM (Robert DeMers) (11/06/90)
According to the EVA Catalog Tools and Equipment, there are several manual tools for dealing with failures of the cargo bay doors to open, close, or latch. Examples: 1/4-inch allen wrench extension for 3/8-inch drive This is used to disconnect the radiator deployment mechanism in the event it fails. Centerline latch bypass tool This is used to bypass a failed cargo bay door centerline latch. An astronaut enters the cargo bay and puts a couple of clamps across the joint in the doors.
henry@zoo.toronto.edu (Henry Spencer) (11/06/90)
In article <1990Nov3.165738.10366@uokmax.ecn.uoknor.edu> jabishop@uokmax.ecn.uoknor.edu (Jonathan A Bishop) writes: >>>... Would this pose serious problems, given that the >>>door-mounted radiators would be unable to vent excess heat into space? > >>It would mean a mission abort and a prompt reentry... > >Could they not also EVA at this point? ... I *think* the normal procedure on today's "operational" flights is to abort if there is a major problem with the doors, on the theory that trouble opening them might mean worse trouble closing them. I could be wrong. This rule might also get modified on urgent or time-critical missions. -- "I don't *want* to be normal!" | Henry Spencer at U of Toronto Zoology "Not to worry." | henry@zoo.toronto.edu utzoo!henry
gckaplan@sag4.ssl.berkeley.edu (George C. Kaplan) (11/25/90)
In article <1990Nov5.183601.9885@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes: > [...discussion of abort vs. EVA if the doors won't open...] > >I *think* the normal procedure on today's "operational" flights is to abort >if there is a major problem with the doors, on the theory that trouble >opening them might mean worse trouble closing them. I could be wrong. >This rule might also get modified on urgent or time-critical missions. Wouldn't they also be constrained by the time it takes to prepare for an EVA? The astronauts doing the EVA have to prebreathe pure oxygen for some time (hours?) before they can safely handle the low pressure of the suits. How long does it take to get ready for an EVA, and how much time do they have if the doors are stuck closed? George C. Kaplan Internet: gckaplan@ssl.berkeley.edu Center for EUV Astrophysics gckaplan%ssl@jade.berkeley.edu University of California UUCP: ...!ucbvax!sunspot.ssl!gckaplan Berkeley, CA 94720 (415) 643-5651
brndlfly@athena.mit.edu (Matthew T Velazquez) (11/26/90)
It takes an astronaut about 3 to 4 hours of breathing pure oxygen to remove dissolved nitrogen from his bloodstream, as well as some God-awful time to get the suit on (presumably these can be more or less simultaneous). T Velazquez Massachusetts Institute of Technology Department of Aeronautics and Astronautics brndlfly@athena.mit.edu