erci18@castle.ed.ac.uk (A J Cunningham) (11/21/89)
I was sitting with my SO watching a programme which included some shuttle footage when my SO turned and asked me "How do they get it pointing up for launch?" I mumbled something about large cranes. Later I was asked "How do they get it on the back of the 747?" I muutered more about even bigger cranes and asked why it was that someone with an economics degree was so interested in shuttle mechanics. Anyway to cut a long story short can anyone provide a better explanation of how you manipulate something as big as a shuttle? Ta, Tony -- Tony Cunningham, Edinburgh University Computing Service. erci18@castle.ed.ac.uk "If the thunder don't get ya then the lightnin' will."
dkrause@orion.oac.uci.edu (Doug Krause) (11/22/89)
In article <1146@castle.ed.ac.uk> erci18@castle.ed.ac.uk (A J Cunningham) writes:
#Anyway to cut a
#long story short can anyone provide a better explanation of how you
#manipulate something as big as a shuttle?
And how is the shuttle supported at launch time? It seems the tank
would be too weak to support the weight of the whole rig.
Douglas Krause One yuppie can ruin your whole day.
----------------------------------------------------------------------
University of California, Irvine Internet: dkrause@orion.oac.uci.edu
Welcome to Irvine, Yuppieland USA BITNET: DJKrause@ucivmsahenry@utzoo.uucp (Henry Spencer) (11/24/89)
In article <1146@castle.ed.ac.uk> erci18@castle.ed.ac.uk (A J Cunningham) writes: >... my SO turned and asked me "How do they get it >pointing up for launch?" I mumbled something about large cranes. Correct. The Vehicle Assembly Building has some, uh, very heavy-duty cranes built in. They set up sort of a frame around the orbiter, to carry the load to points in the orbiter's structure that are meant for this, and the crane picks it up and carries it off. >... "How do they get it on the back of the 747?" ... At Edwards there is a special structure which is essentially a frame with built-in hoisting gear and a 747-sized hole at the bottom. I think there's a similar one at Kennedy. They wheel the orbiter in, hoist it up, and then wheel the 747 in underneath. If NASA had to retrieve an orbiter from an emergency landing site elsewhere, they'd use a special air-transportable derrick plus an ordinary heavy-duty mobile crane. (They tested this when they took the ex-orbiter Enterprise to the New Orleans world's fair.) -- A bit of tolerance is worth a | Henry Spencer at U of Toronto Zoology megabyte of flaming. | uunet!attcan!utzoo!henry henry@zoo.toronto.edu
henry@utzoo.uucp (Henry Spencer) (11/24/89)
In article <3694@orion.cf.uci.edu> dkrause@orion.oac.uci.edu (Doug Krause) writes: >And how is the shuttle supported at launch time? It seems the tank >would be too weak to support the weight of the whole rig. No, the tank is strong enough. It has to be. From assembly to launch, the orbiter hangs on the side of the tank and the tank hangs between the two SRBs. Only the bases of the SRBs are supported. (In fact, the bases of the SRBs are bolted to the mobile pad, using pad-mounted bolts and great big explosive nuts. The nuts are blown at the same instant that the SRB igniters fire.) -- A bit of tolerance is worth a | Henry Spencer at U of Toronto Zoology megabyte of flaming. | uunet!attcan!utzoo!henry henry@zoo.toronto.edu
jbayer@ispi.UUCP (Jonathan Bayer) (11/24/89)
henry@utzoo.uucp (Henry Spencer) writes: >In article <1146@castle.ed.ac.uk> erci18@castle.ed.ac.uk (A J Cunningham) writes: >>... "How do they get it on the back of the 747?" ... >then wheel the 747 in underneath. If NASA had to retrieve an orbiter from >an emergency landing site elsewhere, they'd use a special air-transportable >derrick plus an ordinary heavy-duty mobile crane. (They tested this when >they took the ex-orbiter Enterprise to the New Orleans world's fair.) It was also used when the shuttle landed at White Sands unexpectedly due to bad weather at Edwards a few years ago. JB -- Jonathan Bayer Intelligent Software Products, Inc. (201) 245-5922 500 Oakwood Ave. jbayer@ispi.COM Roselle Park, NJ 07204
edsall@maxwell.physics.purdue.edu (David M. Edsall) (11/28/89)
I think they rub it up and down or put a girl shuttle next to it and see if that gets it up. - dave
dant@mrloog.WR.TEK.COM (Dan Tilque) (11/29/89)
edsall@maxwell.physics.purdue.edu.UUCP (David M. Edsall) writes: > > I think they rub it up and down or put a girl shuttle next to it >and see if that gets it up. I thought it was a well known fact that shuttles only mated with 747's. Nine months later they get a litter of Cesnas... --- Dan Tilque -- dant@mrloog.WR.TEK.COM "There are no Communists left in China." -- Chiang Kai-shek, 1939
thomas@mvac23.UUCP (Thomas Lapp) (11/29/89)
> In article <3694@orion.cf.uci.edu> dkrause@orion.oac.uci.edu (Doug Krause) writes: > >And how is the shuttle supported at launch time? It seems the tank > >would be too weak to support the weight of the whole rig. > > No, the tank is strong enough. It has to be. From assembly to launch, > the orbiter hangs on the side of the tank and the tank hangs between the > two SRBs. Only the bases of the SRBs are supported. (In fact, the bases > of the SRBs are bolted to the mobile pad, using pad-mounted bolts and great > big explosive nuts. The nuts are blown at the same instant that the SRB > igniters fire.) I assume that one of the reasons that shuttle's engines start before the solid boosters is to help counteract the tendency of the whole thing to fall on the orbiter's back? > -- > A bit of tolerance is worth a | Henry Spencer at U of Toronto Zoology > megabyte of flaming. | uunet!attcan!utzoo!henry henry@zoo.toronto.edu - tom -- internet : mvac23!thomas@udel.edu or thomas%mvac23@udel.edu uucp : {ucbvax,mcvax,psuvax1,uunet}!udel!mvac23!thomas Europe Bitnet: THOMAS1@GRATHUN1 Location: Newark, DE, USA Quote : Virtual Address eXtension. Is that like a 9-digit zip code? -- The UUCP Mailer
dkrause@orion.oac.uci.edu (Doug Krause) (11/29/89)
> >And how is the shuttle supported at launch time? It seems the tank > >would be too weak to support the weight of the whole rig. > > No, the tank is strong enough. It has to be. From assembly to launch, > the orbiter hangs on the side of the tank and the tank hangs between the > two SRBs. Only the bases of the SRBs are supported. But what if the weight was concentrated on the base of the tank: ______ / \ | | | | | | | | | | | | | | | | | | \ / -------- ^ |------ like about here Wouldn't that crumble the tank like a Coke can? Douglas Krause One yuppie can ruin your whole day. ---------------------------------------------------------------------- University of California, Irvine Internet: dkrause@orion.oac.uci.edu Welcome to Irvine, Yuppieland USA BITNET: DJKrause@ucivmsa
hogg@db.toronto.edu (John Hogg) (11/29/89)
In article <117.UUL1.3#5131@mvac23.UUCP> mvac23!thomas@udel.edu writes: >I assume that one of the reasons that shuttle's engines start before the >solid boosters is to help counteract the tendency of the whole thing to >fall on the orbiter's back? Were that a problem, it could be solved by starting the boosters and main engines simultaneously. But the stack is resting on the SRBs before they're ignited, so the centres of thrust and gravity should be fairly well matched anyway. Remember that the SSMEs don't thrust through the centre of mass of the orbiter, but rather through that of the whole stack. The sideways ``walk'' resulting from this angled thrust is very noticeable at liftoff. This means that the mains would supply little or no righting torque initially. The overwhelmingly persuasive argument for starting the SSMEs first is that they can be shut down, but the SRBs can't. Once the boosters are lit, the launch is on, regardless of what may follow. The sequenced starting therefore allows the main engines to be checked out while running before the shuttle is irreversibly committed to launch. -- John Hogg hogg@csri.utoronto.ca Department of Computer Science, University of Toronto
henry@utzoo.uucp (Henry Spencer) (11/30/89)
In article <3731@orion.cf.uci.edu> dkrause@orion.oac.uci.edu (Doug Krause) writes: >> No, the tank is strong enough. It has to be. From assembly to launch, >> the orbiter hangs on the side of the tank and the tank hangs between the >> two SRBs. Only the bases of the SRBs are supported. >But what if the weight was concentrated on the base of the tank: >Wouldn't that crumble the tank like a Coke can? It might; I'm not sure. Certainly the tank isn't designed to take that, since it's not a situation that actually occurs. -- That's not a joke, that's | Henry Spencer at U of Toronto Zoology NASA. -Nick Szabo | uunet!attcan!utzoo!henry henry@zoo.toronto.edu
philj@tekig5.PEN.TEK.COM (Phil Jansen) (11/30/89)
Doug Krause: > [H]ow is the shuttle supported at launch time? It seems the tank > would be too weak to support the weight of the whole rig. Henry Spencer: > No, the tank is strong enough. It has to be. From assembly to launch, > the orbiter hangs on the side of the tank and the tank hangs between the > two SRBs. Only the bases of the SRBs are supported. (In fact, the bases > of the SRBs are bolted to the mobile pad, using pad-mounted bolts and great > big explosive nuts. The nuts are blown at the same instant that the SRB > igniters fire.) thomas%mcvac23@udel.edu (tom): > I assume that one of the reasons that shuttle's engines start before the > solid boosters is to help counteract the tendency of the whole thing to > fall on the orbiter's back? Phil Jansen: Actually, they start the main engines first because they can turn them off if there's a problem. This happened with the first aborted launch of Columbia. There was a problem with one of the engines (the turbine driving it wasn't developing enough pressure or something). Only when you know all the main engines work do you light the SRBs -- once those are on you have to launch since they can't be turned off. Both boosters had better start at the same time. The abbreviated schedule is (sorry I don't remember the real T numbers): T-5 Start the main engines in sequence. Bring them up to full power. The shuttle rocks forward (pitches down) as thrust builds. Eventually the shuttle pitches back to vertical from the springiness of the boosters, booster mounts, etc. T+0 At the moment the shuttle is pointing vertically again, fire the explosive bolts and start the boosters. You're leaving. I think one of the explosive bolts failed to blow on one launch; it got pulled off instead (a little extra damage to the pad that time). Everyone, I recommend Space Academy (in Huntsville)! I had a wonderful time and learned a lot! -- If you repeat things often enough, they become true. Phil Jansen If you repeat things often enough, they become true. philj@tekig5.pen.tek.com If you repeat things often enough, they become true.
henry@utzoo.uucp (Henry Spencer) (11/30/89)
In article <117.UUL1.3#5131@mvac23.UUCP> mvac23!thomas@udel.edu writes: >I assume that one of the reasons that shuttle's engines start before the >solid boosters is to help counteract the tendency of the whole thing to >fall on the orbiter's back? Yup. The other reason is that you can abort a launch if problems occur in the orbiter's engines, but once the SRBs fire you are committed, so it makes sense to light the orbiter engines slightly early and see if they work. (There have been one or two aborts at that point.) -- That's not a joke, that's | Henry Spencer at U of Toronto Zoology NASA. -Nick Szabo | uunet!attcan!utzoo!henry henry@zoo.toronto.edu
dodson@mozart.uucp (Dave Dodson) (11/30/89)
In article <1989Nov29.192322.6761@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes: >In article <117.UUL1.3#5131@mvac23.UUCP> mvac23!thomas@udel.edu writes: >>I assume that one of the reasons that shuttle's engines start before the >>solid boosters is to help counteract the tendency of the whole thing to >>fall on the orbiter's back? > >Yup. The other reason is that you can abort a launch if problems occur >in the orbiter's engines, but once the SRBs fire you are committed, so >it makes sense to light the orbiter engines slightly early and see if >they work. (There have been one or two aborts at that point.) Don't forget that it takes several seconds for the turbopumps to ignite and come up to speed to start pumping the fuel and oxidizer into the combustion chamber. Then it takes a while before the thrust reaches acceptable levels. Remember that the Saturn V and many other launchers (maybe all of them?) were held to the pad for several seconds until the thrust built up. They didn't want the thrust to get to where it slightly exceeded the weight, have the vehicle start to move, but not have enough excess thrust to control it and still keep it moving upward. ---------------------------------------------------------------------- Dave Dodson dodson@convex.COM Convex Computer Corporation Richardson, Texas (214) 497-4234
francis@chook.ua.oz (Francis Vaughan) (11/30/89)
From article <1989Nov29.094841.19907@jarvis.csri.toronto.edu>, by hogg@db.toronto.edu (John Hogg): > In article <117.UUL1.3#5131@mvac23.UUCP> mvac23!thomas@udel.edu writes: >>I assume that one of the reasons that shuttle's engines start before the >>solid boosters is to help counteract the tendency of the whole thing to >>fall on the orbiter's back? > > Were that a problem, it could be solved by starting the boosters and > main engines simultaneously. But the stack is resting on the SRBs > before they're ignited, so the centres of thrust and gravity should be > fairly well matched anyway. Remember that the SSMEs don't thrust > through the centre of mass of the orbiter, but rather through that of > the whole stack. The sideways ``walk'' resulting from this angled > thrust is very noticeable at liftoff. This means that the mains would > supply little or no righting torque initially. > > -- > John Hogg hogg@csri.utoronto.ca > Department of Computer Science, University of Toronto One thing I noticed when watching the movie "The dream is alive" (what a buzz, the launch shots really are quite something) is that the exact timing of the ignition sequence may be dependant upon some mundane mechanical factors. When the SSMEs fire the whole stack is noticeably pushed over (ie nose down) then about 2 seconds later starts to swing back again, like a big pendulum. -- I guess the SRBs are flexing, or maybe the actual launch mounts. At the instant the stack is pointing upright again the SRBs are ignited and the thing jumps into the air. I remember someone on the net earlier mentioning that the external tank was not capable of supporting its own weight unless internally pressurised. Of course this probably does not apply to those parts where the orbiter and SRBs are attached. However the nose of the external tank seems to take the brunt of the aerodynamic load. Department of Computer Science Francis Vaughan University of Adelaide francis@cs.ua.oz.au South Australia
pgt@hpfipgt.HP.COM (Paul Tobin) (12/01/89)
| I assume that one of the reasons that shuttle's engines start before the | solid boosters is to help counteract the tendency of the whole thing to | fall on the orbiter's back? I think you're right. Without the shuttle's engines, the weight of the orbiter would pull the whole works over on it's side after lift-off. > -- > A bit of tolerance is worth a | Henry Spencer at U of Toronto Zoology > megabyte of flaming. | uunet!attcan!utzoo!henry henry@zoo.toronto.edu ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Great signature! I know plenty of people in other groups who could learn alot from this. Paul
john@frog.UUCP (John Woods) (12/01/89)
In article <117.UUL1.3#5131@mvac23.UUCP>, thomas@mvac23.UUCP (Thomas Lapp) writes: > I assume that one of the reasons that shuttle's engines start before the > solid boosters is to help counteract the tendency of the whole thing to > fall on the orbiter's back? That might be, though (as a guess) it is also nice to know that the SSMEs are happy and working before turning on the SRBs -- especially since the SSMEs shut down at T-4 seconds one time; having them refuse to start after the SRBs turn on would be much more annoying... -- John Woods, Charles River Data Systems, Framingham MA, (508) 626-1101 ...!decvax!frog!john, john@frog.UUCP, ...!mit-eddie!jfw, jfw@eddie.mit.edu Happiness is Planet Earth in your rear-view mirror. - Sam Hurt
gwh@typhoon.Berkeley.EDU (George William Herbert) (12/02/89)
In article <842@wrgate.WR.TEK.COM> dant@mrloog.WR.TEK.COM (Dan Tilque) writes: > edsall@maxwell.physics.purdue.edu.UUCP (David M. Edsall) writes: >> I think they rub it up and down or put a girl shuttle next to it >>and see if that gets it up. > >I thought it was a well known fact that shuttles only mated with 747's. >Nine months later they get a litter of Cesnas... What is wrong with our shuttle? When the Russians did this, they got a little shuttle! And before the big one had even flown yet... I sense a Shuttle Potency gap here. We're going to have to work on this one... ***************************************************************************** George William Herbert UCB Naval Architecture [On schedule? at UCB? Yes!] gwh@ocf.berkeley.edu gwh@soda.berk... maniac@garnet.berk... ----------------------------------------------------------------------------- "And what if I Don't?" "Then, You will die, the Girl dies, everybody dies..." -Heavy Metal |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
petej@phred.UUCP (Pete Jarvis) (12/04/89)
>From article <1989Nov29.094841.19907@jarvis.csri.toronto.edu>, by hogg@db.toronto.edu (John Hogg): >> >When the SSMEs fire the whole stack is noticeably pushed over (ie nose down) >then about 2 seconds later starts to swing back again, like a big pendulum. >-- I guess the SRBs are flexing, or maybe the actual launch mounts. At the > >Department of Computer Science Francis Vaughan >University of Adelaide francis@cs.ua.oz.au >South Australia When the SSME ignite, causing the stack to sway forward and back again, this is called "twang". The entire stack pivots. The SRB's do not flex. Lift-off is designed for the moment when it returns to vertical again. By this time, the SSME's are up to operating temperatures and pressures. These are "fast start" engines which require only a few seconds to get going, as opposed to the old Saturn V - type design where it took about 9 seconds. ----------- Peter Jarvis --------- Physio-Control, Redmond, WA.
petej@phred.UUCP (Pete Jarvis) (12/04/89)
In article <5103@tekig5.PEN.TEK.COM> philj@tekig5.PEN.TEK.COM (Phil Jansen) writes: > >I think one of the explosive bolts failed to blow on one launch; it >got pulled off instead (a little extra damage to the pad that time). > >Everyone, I recommend Space Academy (in Huntsville)! I had a wonderful time >and learned a lot! > >Phil Jansen If you repeat things often enough, they become true. I haven't heard about any of the bolts failing during a Shuttle launch. As it is, there are 2 charges within the (actually they are nuts), and either charge is designed to break the nut open. The chance of a nut failing at launch is very minute. I have only heard of one or two cases in all of U.S. rocket history. By-the-way, you are right about Space Academy. I've been there 3 times. The last time was 2 months ago. Peter Jarvis...........Physio-Control Redmond, WA.
stealth@caen.engin.umich.edu (Mike Peltier) (12/05/89)
In article <117.UUL1.3#5131@mvac23.UUCP> mvac23!thomas@udel.edu writes: > >I assume that one of the reasons that shuttle's engines start before the >solid boosters is to help counteract the tendency of the whole thing to >fall on the orbiter's back? > Wrong-o. Give these engineers some credit, willya? I'm going to be one of them in a few years... The reason the SME's are lit first is simply that you can turn them off, while the SRBs are considerably more difficult to snuff. Recall that launch a couple of years back where the SMEs fired for about a second and a half and then shut down? If that had happened after the SRBs were lit, there would have been considerably more problems to deal with. -- - - - - - - - - - Michael V. Peltier | Computer Aided Engineering Network 1420 King George Blvd. | University of Michigan, Ann Arbor Ann Arbor, MI 48104-6924 | stealth@caen.engin.umich.edu
grimesga@ingr.com (Greg Grimes) (12/06/89)
In article <1989Nov29.192322.6761@utzoo.uucp>, henry@utzoo.uucp (Henry Spencer) writes: > In article <117.UUL1.3#5131@mvac23.UUCP> mvac23!thomas@udel.edu writes: > >I assume that one of the reasons that shuttle's engines start before the > >solid boosters is to help counteract the tendency of the whole thing to > >fall on the orbiter's back? > > Yup. The other reason is that you can abort a launch if problems occur > in the orbiter's engines, but once the SRBs fire you are committed ... I always thought it had to do the thrust ramp up time of the mains vs. the SRBs. Seems that the thrust curve for the SRBs is almost instantaneously max while the mains take a few seconds to reach max. -- -- Greg Grimes | These opinions are solely mine and Intergraph Corp. | in no way reflect those of my employer. Huntsville, Alabama | uunet!ingr!fed_fe!greg | :-)
dsmith@hplabsb.HP.COM (David Smith) (12/08/89)
In article <2871@phred.UUCP> petej@phred.UUCP (Pete Jarvis) writes: >When the SSME ignite, causing the stack to sway forward and back again, >this is called "twang". The entire stack pivots. The SRB's do not flex. ^^^^^ ^^^^^^ ^^^^^ ^^ ^^^ ^^^^ Says who? David R. Smith, HP Labs dsmith@hplabs.hp.com (415) 857-7898 ------------------------------------------------------------------------- |"Meanwhile Newton became as mad as a hatter: by 1692 he was suffering | |from depression, paranoia, insomnia and forgetfulness, and his hands | |shook. Poor Newton's scientific work was impaired but in that state | |he was judged fit for public office and went on to become Master of | |the Mint and a Member of Parliament." -- Nigel Calder | -------------------------------------------------------------------------
petej@phred.UUCP (Pete Jarvis) (12/11/89)
In article <5519@hplabsb.HP.COM> dsmith@hplabsb.UUCP (David Smith) writes: >In article <2871@phred.UUCP> petej@phred.UUCP (Pete Jarvis) writes: >>When the SSME ignite, causing the stack to sway forward and back again, >>this is called "twang". The entire stack pivots. The SRB's do not flex. > ^^^^^ ^^^^^^ ^^^^^ ^^ ^^^ ^^^^ >Says who? > > David R. Smith, HP Labs David, if you've got something to add, why don't you? The orbiter stack *does* pivot. You can easily see it. The SRB's move as a unit with the orbiter during "twang". Peter Jarvis, Physio-Control