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#3620
by
Fequalsma
on 29 Aug, 2019 01:21
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Pretty sure that the entire Xo 576 bulkhead is flat, not angled above Zo 420. See photo of 576 without the insulation liner.
F=ma
Quick question to settle a discussion I'm having: The forward edges of the orbiter midbody sidewalls are perfectly vertical when seen from the side, is this correct? There's no angle to them? I'm talking about where the midbody joins with the lower forward fuselage half.
Edit:To make the question a bit more clear, is the interpretation of the attached schematic correct? Teal vertical line being the bottom of the Xo576 bulkhead, green horizontal line the PLBD hinge line at Zo420 and the red diagonal line the tilted upper section of the Xo576 bulkhead.
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#3621
by
DaveS
on 29 Aug, 2019 14:48
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Pretty sure that the entire Xo 576 bulkhead is flat, not angled above Zo 420. See photo of 576 without the insulation liner.
F=ma
It has to be to account the canted upper forward fuselage aft face. Or are you saying that the entire bulkhead is angled in the X-Z plane?
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#3622
by
Hog
on 30 Aug, 2019 16:02
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During STS-107, COlumbia had her internal airlock, then furthur aft there is a tunnel running back to the Spacehab Research Double Module (RDM).
In the case of an on-orbit rescue, who would astros have exitted and entered Columbia?
attachments a wiki diagram of the RDM SPaceHab. Is that round "cover" on top of the mid deck to Spacehab, a hatch cover?
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#3623
by
penguin44
on 31 Aug, 2019 04:50
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There is an airlock in the top section of the jog (the connecting tunnel) to allow EVA in case of unforseen issues. You can see the top hatch on the right.
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#3624
by
Ilikeboosterrockets
on 12 Sep, 2019 22:13
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Random question, apologies if it's been asked before.
How much control authority do the flight control surfaces (especially the vertical tail) have at high aoa and reentry velocity+altitude? I've read that the shuttle pulls high alpha S-turns in early stages of reentry, but I can't imagine the control surfaces are especially effective in that regime. I was specifically wondering about the vertical tail, as it almost seems like it would be in the "shadow" of the leading edge of the wing+the fuselage, especially if there's flow separation?
Thanks
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#3625
by
mkirk
on 12 Sep, 2019 23:21
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Random question, apologies if it's been asked before.
How much control authority do the flight control surfaces (especially the vertical tail) have at high aoa and reentry velocity+altitude? I've read that the shuttle pulls high alpha S-turns in early stages of reentry, but I can't imagine the control surfaces are especially effective in that regime. I was specifically wondering about the vertical tail, as it almost seems like it would be in the "shadow" of the leading edge of the wing+the fuselage, especially if there's flow separation?
Thanks
For most of the entry phase (starting at Mach 25 and 400,000 feet in altitude) the orbiter is at a high 40 degree angle of attack (alpha) - which as you surmised, washes out the tail. The angle of attack begins to ramp down beginning at around Mach 10 as the orbiter aerodynamics change from separated flows to the more conventional laminar flows that we are accustomed to with traditional airplane flight.
When the orbiter performs a roll reversal at the higher Mach numbers it is really a yaw maneuver because the orbiter is rolling around the velocity vector. Remember the 40 degree alpha means that the velocity vector is 40 degrees away from the the orbiters roll axis.
So, to answer your question, these rolls around the velocity vector are initiated by a combination of yaw jets and - and as the altitude decreases and dynamic pressure builds up - deflection of the elevons (used to intentionally induce adverse yaw).
Beginning at Mach 10 (which occurs in the neighborhood of 170,000 to 165,000 feet in altitude) the angle of attack is slowly reduced, and the speed-brake function of the rudder assembly is used as a trim/stability device. Both sides of the rudder panels deploy which produces a pitch up moment. This pitch up moment also increases the effectiveness of the elevons (hence the trim function).
At about Mach 5 (~ 115,000 feet in altitude), and an alpha of around 22 degrees and slowly decreasing, the rudder/speed-brake assembly transitions to a more conventional rudder function.
Mark Kirkman
“Space Shuttle Hugger”
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#3626
by
TMI
on 15 Sep, 2019 10:38
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I watched a video some time ago from a man that worked at or with NASA at the beginning of the Shuttle program, he talked about the data bus, programming in high level vs assembler and the tests they ran at the time, and how they simulated the rocket to test computer systems.
I recall a brown stage area and that it was some kind of official NASA talk, but that could be wrong.
Does anyone know what this video was and is it available to the public?
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#3627
by
Hog
on 01 Nov, 2019 13:25
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This question sort of relates to a question previous dealing with the split tail/speedbrake and it being "washed out" at high AoA's.
After the main landing gear(MLG) settles down on the runway, the parachute is deployed before the nose landing gear(NLG) touches down. As the parachute reefs, is there an off center force experienced by the orbiter that wants to pull the nose of upwards?
Was the parachute "reefing" perceptible to the crew?
As I understand it, the chute is deployed and the commander uses the "trim" controls to bring the nose down rather than using the stick to bring the nose down. Does the parachute force affect this trimming prior to NLG touchdown?
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#3628
by
DaveS
on 15 Dec, 2019 23:40
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Does someone know the Xo coordinates of the two points on the attached photo?
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#3629
by
amirghanbariir
on 19 Dec, 2019 13:38
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#3630
by
JAFO
on 09 Jan, 2020 15:34
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Was any thought ever given to doing STS as an inline vehicle from scratch, with the SSMEs on the ET?
Now that I think about it, it would have meant losing the SSMEs along with the ET, defeating the purpose/selling point of a near fully reuseable vehicle, so I doubt it was ever considered. Bummer, as it would have given a better system from the beginning.
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#3631
by
PahTo
on 09 Jan, 2020 15:36
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Was any thought ever given to doing STS as an inline vehicle from scratch, with the SSMEs on the ET?
Now that I think about it, it would have meant losing the SSMEs along with the ET, defeating the purpose/selling point of a near fully reuseable vehicle, so I doubt it was ever considered. Bummer, as it would have given a better system from the beginning.
The "original" design called for the core to be recoverable (usually as a winged first stage) with the orbiter stacked on top as the orbital stage--so yes, early designs were in-line and fully recoverable.
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#3632
by
DaveS
on 18 Jan, 2020 04:00
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I need some light on a shuttle GN&C term here. When talking about a certain attitude, in some cases it has the prefix of "Bias". What is this and how was it determined? For example, some of the attitudes flown during STS-107 was "BIAS -ZLV -XVV"? How did this attitude differ from a regular "-ZLV -XVV" attitude?
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#3633
by
Jorge
on 18 Jan, 2020 16:30
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I need some light on a shuttle GN&C term here. When talking about a certain attitude, in some cases it has the prefix of "Bias". What is this and how was it determined? For example, some of the attitudes flown during STS-107 was "BIAS -ZLV -XVV"? How did this attitude differ from a regular "-ZLV -XVV" attitude?
Unfortunately, there's no simple answer for this because it depends on the purpose of the bias. For example, while docked to ISS, the shuttle was in a BIAS -XLV -ZVV attitude. In this case, the purpose of the bias was to put the shuttle-ISS stack in a torque equilibrium attitude to minimize ISS prop usage. STS-107 didn't dock so that's not it, obviously, but unless you know the purpose of the bias (comm? thermal? payloads?) you won't know how it was determined.
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#3634
by
libra
on 26 Feb, 2020 08:33
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#3635
by
DaveS
on 01 Apr, 2020 23:11
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Anyone know if this screenshot from STS-131 shows the Ku band antenna dish in the MIP (Master Index Pulse) position?
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#3636
by
pilecarls8
on 04 May, 2020 15:54
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Though the space shuttle accomplished quite a bit, we all know that the Shuttle was a grand fiasco in design, safety, and especially cost. It was responsible in the end for NASA decisively losing the rocket battle to the private sector. But given that NASA consists of thousands of people with as much expertise in spaceflight as anyone (and more than anyone else in the 70s), I'm left wondering how it all stacked up like this.
I heard that back in the 70s, they wanted a reusable spacecraft to cheapen the costs of spaceflight. Did not the NASA people realize that the Shuttle might cost more than a low cost expendable system, and/or that for a reusable design the shuttle was an odd and extremely inefficient way to go? Or was this nothing more than a cosmic miscalculation and failure by NASA?(I know it's because in those days there was no KSP)
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#3637
by
nacnud
on 04 May, 2020 16:04
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There are a lot of threads on this, it's a fascinating story. I suggest taking a look through the many many threads on this already.
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#3638
by
Kansan52
on 04 May, 2020 16:06
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Hubris.
In my opinion.
Cost pressures were intense. Apollo, Apollo Test follow ons, upgraded Saturn V, NERVA, ect. were chopped. Human Spaceflight was on the chopping block and self delusion said the Space Transportation System would save HSF.
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#3639
by
Svetoslav
on 04 May, 2020 16:06
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We've had this discussion numerous times so I'm not sure if it's good to open this topic again. After all, most of the people would agree that:
1. If we judge the Space Shuttle by the original goals of the program - safety, frequent launches, and affordability so not only government astronauts would fly to space, but also ordinary people... yes, the program was a failure.
2. If we judge the Space Shuttle by things accomplished, especially when compared to other crewed programs - total number of people launched to space, Spacelab missions, construction of the ISS and Hubble servicing missions - the program was highly successful.
But then you ask : "Did not the NASA people realize that the Shuttle might cost more than a low cost expendable system?" - I think you're missing a point. Pursuing the goal itself isn't bad. Choosing reusability vs low cost expendable systems is a noble goal - but we may agree that the way NASA tried to do it, via the Space Shuttle, was not an optimal/affordable approach. I don't think many people here will disagree. And most of them won't disagree that Elon Musk's approach towards reusability, which we see with the Falcon rockets and later with Starship, has a bigger potential to succeed.
