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#2720
by
craigcocca
on 28 Sep, 2012 19:07
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Was the ET that was shipped to Port Hueneme in California via the Panama Canal in 1985 ever returned to KSC? If not, what became of it?
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#2721
by
Jim
on 28 Sep, 2012 20:55
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Was the ET that was shipped to Port Hueneme in California via the Panama Canal in 1985 ever returned to KSC? If not, what became of it?
It was shipped to VAFB and not Port Hueneme. It was returned to MSFC I believe.
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#2722
by
craigcocca
on 29 Sep, 2012 04:36
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I've read in a number of books that the plan was to ship and store the ETs at port Hueneme, and then move them by hovercraft to VAFB. Is that inaccurate?
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#2723
by
Jim
on 29 Sep, 2012 12:23
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I've read in a number of books that the plan was to ship and store the ETs at port Hueneme, and then move them by hovercraft to VAFB. Is that inaccurate?
Yes, it is inaccurate. That concept changed died in the mid 70's. There is a boat dock created for the standard ET barge at VAFB and Delta IV now uses it.
http://goo.gl/maps/MnQv7
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#2724
by
craigcocca
on 29 Sep, 2012 20:58
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I've read in a number of books that the plan was to ship and store the ETs at port Hueneme, and then move them by hovercraft to VAFB. Is that inaccurate?
Yes, it is inaccurate. That concept changed died in the mid 70's. There is a boat dock created for the standard ET barge at VAFB and Delta IV now uses it.
http://goo.gl/maps/MnQv7
Thanks, never knew that dock existed at VAFB!
For future posterity, here are the four tanks that were shipped to Vandenberg in 1985-86, along with their final disposition:
ET-23: Launched with STS-27 (DoD)
ET-27: Launched with STS-34 (Galileo)
ET-33: Launched with STS-36 (DoD)
ET-34: Launched with STS-31 (HST)
Looks like the Air Force got some use out of two of the four tanks in the end.
-Craig
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#2725
by
NavySpaceFan
on 02 Oct, 2012 16:10
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I'm looking for anything related to Endeavour's OMM, specifically milestone dates, work performed, flow manger at the time, etc. Thanks!
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#2726
by
rbfnet
on 10 Oct, 2012 13:59
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Question about abort boundaries: During ascent, there will be a transition through the following flour states:
(1) If a single engine is lost, the shuttle cannot make a safe/stable orbit period.
(2) If a single engine is lost, the shuttle can make a safe/stable orbit if an ATO is called.
(3) If a single engine is lost, and no ATO is called, the shuttle will not make its desired orbit, but it will (at the time shutdown occurs as a result of ECO sensors going dry) make a safe/table orbit.
(4) If a single engine is lost, and no ATO is called, the shuttle will, on two engines, make it to a normal guidance-initiated shutdown in it's desired orbit.
(Obviously I haven't listed all the abort boundaries above ... just enough to frame my question.)
Is the transition from "ATO" to "Press to MECO" (for single engine failure) at the transition from (2) to (3) above, or from (3) to (4) above?
Or, put another way, during the period of time where flying on two engines without an ATO call will lead to a safe/stable orbit, but not the desired orbit, is the practice to call ATO on single engine loss, or to press to MECO on single engine loss (knowing that it will likely be an ECO-initiated shutdown prior to desired orbit).
Secondary question: When an ATO occurs, does the shuttle always fly to propellant exhaustion (ECO-initiated shutdown)? Or does abort guidance initiate a shutdown when some acceptable orbit has been attained?
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#2727
by
alk3997
on 11 Oct, 2012 13:37
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Question about abort boundaries: During ascent, there will be a transition through the following flour states:
(1) If a single engine is lost, the shuttle cannot make a safe/stable orbit period.
(2) If a single engine is lost, the shuttle can make a safe/stable orbit if an ATO is called.
(3) If a single engine is lost, and no ATO is called, the shuttle will not make its desired orbit, but it will (at the time shutdown occurs as a result of ECO sensors going dry) make a safe/table orbit.
(4) If a single engine is lost, and no ATO is called, the shuttle will, on two engines, make it to a normal guidance-initiated shutdown in it's desired orbit.
(Obviously I haven't listed all the abort boundaries above ... just enough to frame my question.)
Is the transition from "ATO" to "Press to MECO" (for single engine failure) at the transition from (2) to (3) above, or from (3) to (4) above?
Or, put another way, during the period of time where flying on two engines without an ATO call will lead to a safe/stable orbit, but not the desired orbit, is the practice to call ATO on single engine loss, or to press to MECO on single engine loss (knowing that it will likely be an ECO-initiated shutdown prior to desired orbit).
Secondary question: When an ATO occurs, does the shuttle always fly to propellant exhaustion (ECO-initiated shutdown)? Or does abort guidance initiate a shutdown when some acceptable orbit has been attained?
You're kind-of all over the place with your description of "abort boundaries". Abort boundaries were simply velocity versus abort capability. In other words, at this feet / sec, the orbiter could had this capability to reach a landing site or orbit, assuming we were on the standard ascent flight profile.
For intact abort modes, which were RTLS, TAL and ATO, based on payload weights and engine capabilities (and other things) there were a set of velocity cutoffs that said at this point you have both RTLS and TAL capability or you no longer have RTLS capability (negative return). Intact aborts covered all single engine out cases, while contingency aborts included two-engine outs, three-engine outs as well as stuck throttles and other unusual cases. The abort boundary velocities were computed months before flight and then updated on the day of flight.
For ATO, there was a velocity that allowed us to recompute (in real-time), the orbit targets and get to the best orbit we could (such as on STS-51F). This orbit was less than the target orbit but was a stable orbit where the situation could be assessed. Once we hit the single-engine-out MECO velocity, then we could make the normal MECO targets (and therefore the desired orbit) even if one engine was out. ECO sensor dry MECOs are a completely separate subject than intact or contingency aborts since that happens so close to your normal MECO targets that an OMS burn could have made-up any deficiencies (but with the loss of OMS prop).
Contingency aborts had quite a number of permutations as different boundaries were available for two-engine out and three-engine out cases. The intent was to always have a runway available for each of these cases but there were situations (called black-zones) where a runway was not available. For these east coast abort landing contingency aborts, during later flights an onboard display was available that gave the crew a rough idea of which runways were reachable (both in the US and in Europe). Unfortunately we never really had time to fully integrate the use of the display but fortunately it was never really needed.
Finally, I did not include AOA above because the RTLS/TAL/ATO intact aborts covered the entire velocity range to orbit. So, AOA became only necessary for multiple failure scenarios (SSME out plus OMS problem, for instance).
Also note that all of my answers are in the past tense since the program is well over now. That means I'm also relying on my memory, so any details should be double-checked.
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#2728
by
spacecane
on 13 Oct, 2012 02:24
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Let me preface this by saying that I am nothing near a rocket scientist so this could be a really dumb question.
Could the External Tank have been made 25% or so smaller (and a decent percentage lighter) if the SSMEs didn't ignite until staging? Even with the 25% lighter liquid fuel/oxidizer load could the SRBs alone have lifted the stack off the pad and got it high/fast enough at staging for the SSMEs to take the orbiter the rest of the way into orbit?
I have always wondered if the use of the SSMEs prior to liftoff was a performance issue or if the system was designed that way solely to have the ability to evaluate SSME function prior to liftoff. I would imagine that without a launch escape system there would be a pretty big risk if the engines didn't start at staging.
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#2729
by
Danny Dot
on 13 Oct, 2012 16:39
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Press to MECO is not based on making the nominal MECO targets. I is based on keeping the tank off a land mass.
Danny Deger
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#2730
by
AS-503
on 13 Oct, 2012 17:15
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Let me preface this by saying that I am nothing near a rocket scientist so this could be a really dumb question.
Could the External Tank have been made 25% or so smaller (and a decent percentage lighter) if the SSMEs didn't ignite until staging? Even with the 25% lighter liquid fuel/oxidizer load could the SRBs alone have lifted the stack off the pad and got it high/fast enough at staging for the SSMEs to take the orbiter the rest of the way into orbit?
I have always wondered if the use of the SSMEs prior to liftoff was a performance issue or if the system was designed that way solely to have the ability to evaluate SSME function prior to liftoff. I would imagine that without a launch escape system there would be a pretty big risk if the engines didn't start at staging.
You may want to read the Ares-I/CxP details with regard to an air-startable SSME. There was some hefty ground equipment (on the pad), among other things, that get the SSMEs up and running. The original Ares 1 design had a 4 segment SRB and a single SSME (air-start) upper stage. The air-start was not impossible but it was not going to be easy OR cost effective.
Also keep in mind that in an overly simplified perspective, the total thrust of all three SSMEs effectively makes the whole stack about 1.1 million pounds "lighter", so the SRB's have less to lift.
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#2731
by
OV135
on 22 Oct, 2012 14:11
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#2732
by
Jim
on 22 Oct, 2012 14:41
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#2733
by
JayP
on 27 Oct, 2012 21:51
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#2734
by
DaveS
on 27 Oct, 2012 22:22
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like the inspection port they stick a borescope thru to check and make sure the latches have all engaged
Not quite. They don't use a borescope for this task but a multimeter to measure the electrical resistance. The resistance should be less than 2.0Ω to indicate an successful latching.
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#2735
by
JayP
on 28 Oct, 2012 03:36
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Actually, they do both a visual and electrical test. I did misspeaks when I said borescope. They actually just use a small mirror on a stick and a flashlight to see if a mark painted on the latch linkage is visable.
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#2736
by
spacecane
on 31 Oct, 2012 02:49
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Does anybody have (or can draw even if crude) a diagram of the angle of the stack vs. direction of travel during ascent (after roll). For some reason I can't picture how the orbiter was at a negative AoA vs. the slip stream when it seams like the forward direction would be somewhat on the ET side (based upon the drift at liftoff).
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#2737
by
Jim
on 31 Oct, 2012 12:28
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Does anybody have (or can draw even if crude) a diagram of the angle of the stack vs. direction of travel during ascent (after roll). For some reason I can't picture how the orbiter was at a negative AoA vs. the slip stream when it seams like the forward direction would be somewhat on the ET side (based upon the drift at liftoff).
By adjusting the thrust vector of the SRB's and SSME's, the vehicle can fly at different attitudes with respect to the flight path.
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#2738
by
Fequalsma
on 12 Nov, 2012 17:56
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Spacecane -
CBS News' Space Place has STS trajectory info available at:
http://www.cbsnews.com/network/news/space/home/flightdata/downloads.htmlDownload either of these files:
STS-135 SpaceCalcMac (Macintosh formatting; Zip archive)
STS-135 SpaceCalcPC (PC formatting; Zip archive)
And look under the Trajectory tab of the SpaceCalc_XXX.xls workbook for the data.
F=ma
Does anybody have (or can draw even if crude) a diagram of the angle of the stack vs. direction of travel during ascent (after roll). For some reason I can't picture how the orbiter was at a negative AoA vs. the slip stream when it seams like the forward direction would be somewhat on the ET side (based upon the drift at liftoff).
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#2739
by
DaveS
on 12 Nov, 2012 21:33
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Anyone know if the pre-launch aerosurface check (T-3:55) and gimbal check (T-3:25) is commanded by the GLS or is it the RSLS that commands those?