sfn20715@uxa.cso.uiuc.edu (09/14/90)
When the shuttle lifts off, what is used to make it turn and roll? (roll/pitch? turn/yaw? you know what I mean...) I would assume that the orbiter's aerodynamic surfaces are not used, as they are not directly exposed to the air, and its not going _that_ fast when it clears the tower and starts the turn, and I would assume that the SSME's are not vectored, right? Which one of these is wrong? BTW, I went to an Illini Space Development Society mtg here at the U of Illinois, and saw a NASA tape about the shuttle trainer. Mostly not too exciting, but there was one really neat shot of one of the CRT's used to simulate the view out of the windows during takeoff. My thoughts went along these lines: "What's that silly cross-hatched stuff they're showing now? Why's it going sideways so fast, and whoops what's that spike, hey its gone, it must have been the launch structure, and wow look at the scenery and woah noooo dont turn over that far you'll fall over, woah stop spinning, augh stop falling so far back!!!" It honestly reminded me of some of the worst rollercoasters I've been on. Must be one hell of a ride in the real thing!
gregc@cimage.com (Greg Cronau/1000000) (09/14/90)
In article <52900004@uxa.cso.uiuc.edu> sfn20715@uxa.cso.uiuc.edu writes: > >When the shuttle lifts off, what is used to make it turn and roll? >(roll/pitch? turn/yaw? you know what I mean...) >I would assume that the orbiter's aerodynamic surfaces are not used, >as they are not directly exposed to the air, and its not going >_that_ fast when it clears the tower and starts the turn, and I would >assume that the SSME's are not vectored, right? Which one of these >is wrong? The SSME's can be gimbaled(sp?) and the SRB's have the ability to gimbal their exhaust nozzles a few degrees. The SRB's have thier own onboard APU's to power the hydralics that drive the nozzle hardware. The SRB's are *alot* more complicated than a couple of pipes stuffed with Solid rocket fuel. gregc@cimage.com
v055mvw3@ubvmsb.cc.buffalo.edu (Gregory J Schaffer) (09/14/90)
In article <52900004@uxa.cso.uiuc.edu>, sfn20715@uxa.cso.uiuc.edu writes... > >When the shuttle lifts off, what is used to make it turn and roll? >(roll/pitch? turn/yaw? you know what I mean...) >I would assume that the orbiter's aerodynamic surfaces are not used, >as they are not directly exposed to the air, and its not going !!!!They AREN'T???!!! What ARE they exposed to? :) >_that_ fast when it clears the tower and starts the turn, and I would >assume that the SSME's are not vectored, right? Which one of these >is wrong? The Space Shuttle's Main Engines have the capability to swivel (I believe the correct term is GIMBLE), and I think, to a *VERY* small degree, so can the SRB skirts. The aerodynamic surfaces (here, the WING) do produce a force component opposite in direction to the external tank as the shuttle flies. I don't know if this, or any movement of the rudder, are used in the roll maneuver. Greg Schaffer University at Buffalo V055MVW3@UBVMS
jabishop@uokmax.uucp (Jonathan A Bishop) (09/14/90)
v055mvw3@ubvmsb.cc.buffalo.edu (Gregory J Schaffer) writes: >The Space Shuttle's Main Engines have the capability to swivel (I >believe the correct term is GIMBLE), and I think, to a *VERY* small >degree, so can the SRB skirts. Yes, the SRB skirts can. They can't move nearly as much as the SSME's, but when they do, I'm sure they generate a hell of a big moment. If you watch NASA Select or some other good news source (i.e., not a network) for the next Shuttle launch, you will probably be able to see the main engine gimbal check and the control surfaces check which occur, if I'm not mistaken, right after APU start up. -- 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
henry@zoo.toronto.edu (Henry Spencer) (09/15/90)
In article <52900004@uxa.cso.uiuc.edu> sfn20715@uxa.cso.uiuc.edu writes: >When the shuttle lifts off, what is used to make it turn and roll? ... >I would assume that the orbiter's aerodynamic surfaces are not used, >as they are not directly exposed to the air, and its not going >_that_ fast when it clears the tower and starts the turn, and I would >assume that the SSME's are not vectored, right? ... Wrong, actually. Both the SSMEs and the SRB nozzles are gimballed. I think the orbiter's aerodynamic surfaces are locked in neutral during ascent, in fact. -- TCP/IP: handling tomorrow's loads today| Henry Spencer at U of Toronto Zoology OSI: handling yesterday's loads someday| henry@zoo.toronto.edu utzoo!henry
clj@ksr.com (Chris Jones) (09/15/90)
In article <1990Sep14.170451.2070@zoo.toronto.edu>, henry@zoo (Henry Spencer) writes: >I think the orbiter's aerodynamic surfaces are locked in neutral during >ascent, in fact. I recall reading in the Rogers Comission report that, in addition to all of the engines gimbaling to try to compensate for the right hand SRB's underthrust, Challenger's rudder was also trying to steer to the left. I also have a vague recollection of Mike Collins describing how the elevons moved during a shuttle launch, an act which he described as "making an old rocket pilot like me nervous." -- Chris Jones clj@ksr.com {world,uunet,harvard}!ksr!clj
shafer@skipper.dfrf.nasa.gov (Mary Shafer) (09/15/90)
In article <36104@eerie.acsu.Buffalo.EDU> v055mvw3@ubvmsb.cc.buffalo.edu (Gregory J Schaffer) writes: In article <52900004@uxa.cso.uiuc.edu>, sfn20715@uxa.cso.uiuc.edu writes... > >When the shuttle lifts off, what is used to make it turn and roll? >(roll/pitch? turn/yaw? you know what I mean...) >I would assume that the orbiter's aerodynamic surfaces are not used, >as they are not directly exposed to the air, and its not going !!!!They AREN'T???!!! What ARE they exposed to? :) >_that_ fast when it clears the tower and starts the turn, and I would >assume that the SSME's are not vectored, right? Which one of these >is wrong? The Space Shuttle's Main Engines have the capability to swivel (I believe the correct term is GIMBLE), and I think, to a *VERY* small degree, so can the SRB skirts. The nozzles gimble, not the SSMEs. The aerodynamic surfaces (here, the WING) do produce a force component opposite in direction to the external tank as the shuttle flies. I don't know if this, or any movement of the rudder, are used in the roll maneuver. The whole shuttle is an aerodynamic surface producing lift (your force opposite in direction to the external tank) out the top of the shuttle (can you say "lifting body"?) which is a better way of referring to it than as opposite the external tank. This lift isn't dependent on the location of the external tank, so it's confusing to phrase it this way. Did you mean control surfaces (ailerons, rudder, and body flap) were used in the roll? The lift would, at most, produce a pitching moment, not a rolling moment. -- Mary Shafer shafer@skipper.dfrf.nasa.gov ames!skipper.dfrf.nasa.gov!shafer NASA Ames Dryden Flight Research Facility, Edwards, CA Of course I don't speak for NASA "A MiG at your six is better than no MiG at all"--Unknown US fighter pilot
rinne@mcnc.org (Glenn A. Rinne) (09/15/90)
In article <SHAFER.90Sep14154432@skipper.dfrf.nasa.gov> shafer@skipper.dfrf.nasa.gov (Mary Shafer) writes: > In article <52900004@uxa.cso.uiuc.edu>, sfn20715@uxa.cso.uiuc.edu writes... > > > >When the shuttle lifts off, what is used to make it turn and roll? > >(roll/pitch? turn/yaw? you know what I mean...) > >The whole shuttle is an aerodynamic surface producing lift (your force >opposite in direction to the external tank) out the top of the shuttle >(can you say "lifting body"?) which is a better way of referring to it >than as opposite the external tank. This lift isn't dependent on the >location of the external tank, so it's confusing to phrase it this >way. Did you mean control surfaces (ailerons, rudder, and body flap) >were used in the roll? The lift would, at most, produce a pitching >moment, not a rolling moment. > The original question referred to the need for the roll just after liftoff. Looking at the Shuttle stack, wouldn't the center of thrust (given the SRB's large thrust) be on the orbiter side of the stack? If so, the 180 degree roll may facilitate using the SMEs to control the trajectory. Since the SMEs can vector (gimbal) thrust more effectively, they may be more effective in a _pitch-up_ mode rather than a _pitch-down_ mode, given the ballistic tendency of stack. >-- > "A MiG at your six is better than no MiG at all"--Unknown US fighter pilot My brother (a United co-pilot) and I love your .sig Glenn Rinne MCNC Center for Microelectronics RTP, NC, 27709-2889 rinne@mcnc.org.UUNET
john@chinet.chi.il.us (John Mundt) (09/16/90)
In article <7082@alvin.mcnc.org> rinne@mcnc.org.UUCP (Glenn A. Rinne) writes: >In article <SHAFER.90Sep14154432@skipper.dfrf.nasa.gov> shafer@skipper.dfrf.nasa.gov (Mary Shafer) writes: >The original question referred to the need for the roll just after liftoff. >Looking at the Shuttle stack, wouldn't the center of thrust (given the SRB's >large thrust) be on the orbiter side of the stack? If so, the 180 degree >roll may facilitate using the SMEs to control the trajectory. What I never understood was why not turn the thing around in the VAB and drive it out to the launch pad the other way. Then there would be no need for the fancy rotation. Put the TV cameras on the other side and everyone is happy. Was the tower built for the Apollo program and thus in the wrong orientation? -- --------------------- john@admctr.chi.il.us John Mundt Teachers' Aide, Inc. P.O. Box 1666, Highland Park, IL (708) 998-5007 || -432-8860
clyde@emx.utexas.edu (Clyde W. Hoover) (09/17/90)
In article <1990Sep16.012312.9303@chinet.chi.il.us>, john@chinet.chi.il.us (John Mundt) writes: |> |> What I never understood was why not turn the thing around in the VAB and |> drive it out to the launch pad the other way. Then there would be no need |> for the fancy rotation. Put the TV cameras on the other side and everyone |> is happy. You don't see it very often, but the Shuttle service tower almost wraps around the back of the External Tank. There is a liquid hydrogen vent arm that attaches to the ET in about the middle of the "back" (anti-TV side). This arm is pretty short (in comparsion to the LOX "beanie cap" and crew access arms). The track for the Rotating Service Structure also rests mostly on the "up-ramp" of the pad. In short, the pad was re-engineered for the shuttle to be set the way that it is. The "upside down" orientation during ascent is an unrelated issue. |> Was the tower built for the Apollo program and thus in the |> wrong orientation? Close: 1. The pads at LC 39 were placed for the launch azimuth for lunar transfer orbit. 2. The Saturn V did perform a 'roll' manuever after launch - but being a symmetric vechile, did not actually have to rotate. The Shuttle is not symmetric, and thusly has to rotate around the X (I think that's the right one) axis to achive the proper azimuth. -Clyde Hoover Shouter-To-Dead-Parrots @ Univ. of Texas Computation Center; Austin, Texas clyde@emx.utexas.edu; ...!cs.utexas.edu!ut-emx!clyde Tip #268: Don't feel insecure or inferior! Remember, you're ORGANIC!! You could win an argument with almost any rock!
roy@phri.nyu.edu (Roy Smith) (09/17/90)
In <37261@ut-emx> clyde@emx.utexas.edu writes:
-> The Saturn V did perform a 'roll' manuever after launch - but being a
-> symmetric vechile, did not actually have to rotate.
How does one perform a roll without actually rotating?
--
Roy Smith, Public Health Research Institute
455 First Avenue, New York, NY 10016
roy@alanine.phri.nyu.edu -OR- {att,cmcl2,rutgers,hombre}!phri!roy
"Arcane? Did you say arcane? It wouldn't be Unix if it wasn't arcane!"v071pzp4@ubvmsd.cc.buffalo.edu (Craig L Cole) (09/17/90)
A couple of comments on the following thread:
1) Both the SSMEs and SRMs gimble - if you watch NASA select before
a launch, they'll show the gimble test. The SSMEs move quite a bit!
2) The shuttle DOES use its aerodynamic surfaces to help stabilize
the launch trajectory. In the Roger's Report, Challenger's
aerodynamic surfaces were trying in vain to keep the stack
together as the stack ripped apart due to stress.
3) As I understand it, the shuttle roll is to alter the shuttle's
orbital inclination. The "standard" shuttle inclination is
about 28 degrees above the equator. The shuttle can reach over
60 degrees. The roll helps point it in the right direction.
A shuttle can obtain its usual upside-down position
without rolling. Stand upright, call your front the shuttle,
your back the ET. At launch, all you'd have to do to have the
shuttle upside down is bend over forward.
Say you're facing east and want to head north. Turn at the same
time as you bend forward and you'll have just imitated a typical
shuttle roll!
4) I know the shuttle has to fly upside down to reduce stresses,
but I'm not sure where the stress are lowered. My guess is, the
ET takes the brunt of the shock wave the stack creates, letting
the shuttle ride in its "wake." Which would explain why the shuttle
can't pop off of the ET before the SRB's are spent whithout
aerodynamic stresses ripping the shuttle apart (like Challenger).
I don't work for NASA or anything (yet) so I'm not 100% sure of any
of this. But I like to think some of its right!
Craig Cole
University at Buffalo
V071PZP4@UBVMS.BITNET
V071PZP4@UBVMS.CC.BUFFALO.EDUbrody@eos.UUCP (Adam R. Brody) (09/18/90)
clyde@emx.utexas.edu (Clyde W. Hoover) writes: >2. The Saturn V did perform a 'roll' manuever after launch - but being a > symmetric vechile, did not actually have to rotate. The Shuttle is not > symmetric, and thusly has to rotate around the X (I think that's the right > one) axis to achive the proper azimuth. > -Clyde Hoover How does one perform a roll without actually rotating?
gregc@cimage.com (Greg Cronau/1000000) (09/18/90)
In article <1990Sep14.134059.32204@uokmax.uucp> jabishop@uokmax.uucp (Jonathan A Bishop) writes: >v055mvw3@ubvmsb.cc.buffalo.edu (Gregory J Schaffer) writes: > >>The Space Shuttle's Main Engines have the capability to swivel (I >>believe the correct term is GIMBLE), and I think, to a *VERY* small >>degree, so can the SRB skirts. > > Yes, the SRB skirts can. They can't move nearly as much as the SSME's, >but when they do, I'm sure they generate a hell of a big moment. > > If you watch NASA Select or some other good news source (i.e., not a >network) for the next Shuttle launch, you will probably be able to see the >main engine gimbal check and the control surfaces check which occur, if I'm >not mistaken, right after APU start up. The APUs are what provide power to the hydraulic system that moves the aero surfaces and the SSME gimbal hardware. The tests would *have* to occure after the APU startup. gregc@cimage.com
gregc@cimage.com (Greg Cronau/1000000) (09/18/90)
In article <1990Sep16.012312.9303@chinet.chi.il.us> john@chinet.chi.il.us (John Mundt) writes: >In article <7082@alvin.mcnc.org> rinne@mcnc.org.UUCP (Glenn A. Rinne) writes: >>In article <SHAFER.90Sep14154432@skipper.dfrf.nasa.gov> shafer@skipper.dfrf.nasa.gov (Mary Shafer) writes: >>The original question referred to the need for the roll just after liftoff. >>Looking at the Shuttle stack, wouldn't the center of thrust (given the SRB's >>large thrust) be on the orbiter side of the stack? If so, the 180 degree >>roll may facilitate using the SMEs to control the trajectory. > >What I never understood was why not turn the thing around in the VAB and >drive it out to the launch pad the other way. Then there would be no need >for the fancy rotation. Put the TV cameras on the other side and everyone >is happy. Was the tower built for the Apollo program and thus in the >wrong orientation? >-- Well, sort of.... The actual concrete pad, flame trench, and support facilities are the luanch complex 39A/B that all the saturn Vs were launched from. The towers that are permanently fixed to the ground at both pads now, are actually the upper 2/3s of the old towers that used to be attached to the mobil launch platforms. But, I have no idea why the towers were fixed to the north side of the pads vs. the south side. gregc@cimage.com
richt@meaddata.com (richt) (09/25/90)
Speaking of lift-offs, I was wondering if anyone could tell me why
the shuttle is slightly turned right after take-off in the first
place?
Thanks for any info,
Rich
--
I really don't have a .signature file, you're just imagining this one.
/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
*
Richard Thompson richt%meaddata@uunet.uu.net *
Mead Data Central *
3445 Newmark Drive *
Miamisburg, OH 45342 *
(513) 865-1664 *
*
\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/