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#2020
by
Nikola
on 29 Jun, 2011 23:56
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Hi,
does anybody know what is the thickness of the ET thermal insulation foam?
Somehow, I always imagined that it is really tick.
Also, what is the consistency? Can you for example cut a chunk of foam with kitchen knife?
Thanks.
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#2021
by
Namechange User
on 30 Jun, 2011 00:01
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Hi,
does anybody know what is the thickness of the ET thermal insulation foam?
Somehow, I always imagined that it is really tick.
Also, what is the consistency? Can you for example cut a chunk of foam with kitchen knife?
Thanks.
The thickness varies for different parts of the tank. Consistency I guess is harder to answer but the closest analogy I can think of right now is something like styrofoam, and yes it can be cut, shaved, etc.
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#2022
by
Jim
on 30 Jun, 2011 11:51
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Hi,
does anybody know what is the thickness of the ET thermal insulation foam?
Somehow, I always imagined that it is really tick.
Also, what is the consistency? Can you for example cut a chunk of foam with kitchen knife?
Thanks.
It is very similar to this stuff
http://greatstuff.dow.com/This even turns the same color when exposed to sunlight
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#2023
by
DMeader
on 30 Jun, 2011 15:19
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Also, what is the consistency? Can you for example cut a chunk of foam with kitchen knife?
Thanks.
Back in 1995, woodpeckers pecked out nearly 100 holes in the STS-70 ET foam insulation. Needed rolled back to the VAB for repairs.
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#2024
by
Nikola
on 02 Jul, 2011 22:33
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The thickness varies for different parts of the tank. Consistency I guess is harder to answer but the closest analogy I can think of right now is something like styrofoam, and yes it can be cut, shaved, etc.
Yes, I expected it probably varies.
But in what range is it? I mean is it 3 cm or 30cm.
I have another question. Is there any very high quality sound recording of a space shuttle launch? I guess HD video has good sound but it's optimized for video and not sound since it's HD *video*.
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#2025
by
Jason1701
on 03 Jul, 2011 00:01
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This video is amazing.
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#2026
by
kraisee
on 03 Jul, 2011 01:36
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Nikola,
The SOFI varies across the entire structure of the tank. Generally, it is between 0.25" to 1.52" thick on the cryogenic tanking structures. The LH2 tank tends to have the thickest material, the LOX tank uses thinner. The tank domes inside the Intertank are protected from airflow, so they are fairly thin.
The Intertank structure typically has the thinnest material, as thin as 0.15" thick.
The SLWT System Definition Handbook has precise details. Its available in the L2 section.
Ross.
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#2027
by
Nikola
on 03 Jul, 2011 12:39
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Thanks.
It's not a very tick layer. I mean from the appearance of the tank you could think is like 1m tick
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#2028
by
Specifically-Impulsive
on 05 Jul, 2011 22:32
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How fast can each of the individual joints on the RMS move? Also, what are the overall speed limits for the RMS? The RMS speed seems to be limited to 2.0 fps (according to the PDRS documents I've seen), but I'm wondering if this is due to mechanical constraints or just so it doesn't bump into anything.
The rates are set by software based on the mass and inertias of the payload. The 2 fps tip rate is for the unloaded arm. The overriding consideration is that the system should be able to detect a failure and stop motion as long as the payload remains more than five feet from structure (the flight rule limit). Heavy payloads will move much slower than the unloaded arm to protect this stopping distance constraint.
Individual joint rates scale down with the allowable tip rate. If you take the 50 foot arm and figure out what rotational rate gives you 2 fps at the tip, you will be darn close to the shoulder joint rate for unloaded motion.
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#2029
by
JLicklider
on 08 Jul, 2011 05:18
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Im looking for a chart or list of the milestones, speeds, times, MCC calls etc. from T-0 to MECO. I did a search and found the same question asked in the Shuttle Q&A thread number 2, the reply was to see
http://science.ksc.nasa.gov/shuttle/countdown/count.html#T-01M00S but it only goes to T-0. Clicking LIFTOFF on that page takes to a countdown clock but no launch info. (Searching for "launch milestone" on a spaceflight forum returns quite a few results!)
Any ideas?
Joey
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#2030
by
alexw
on 08 Jul, 2011 05:55
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Im looking for a chart or list of the milestones, speeds, times, MCC calls etc. from T-0 to MECO. I did a search and found the same question asked in the Shuttle Q&A thread number 2, the reply was to see http://science.ksc.nasa.gov/shuttle/countdown/count.html#T-01M00S but it only goes to T-0. Clicking LIFTOFF on that page takes to a countdown clock but no launch info. (Searching for "launch milestone" on a spaceflight forum returns quite a few results!)
Any ideas?
Try:
http://spaceflightnow.com/shuttle/sts135/fdf/135ascent.htmlNote that the times may not be exact to the second --- the precise launch window depends on recent updates of the station's position, and they target the center of the window. Although, this version says updated 8 July, so it should be about on the money.
-Alex
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#2031
by
JLicklider
on 08 Jul, 2011 06:04
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Perfect! Thanks!
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#2032
by
tminus9
on 08 Jul, 2011 08:33
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Im looking for a chart or list of the milestones, speeds, times, MCC calls etc. from T-0 to MECO. I did a search and found the same question asked in the Shuttle Q&A thread number 2, the reply was to see http://science.ksc.nasa.gov/shuttle/countdown/count.html#T-01M00S but it only goes to T-0. Clicking LIFTOFF on that page takes to a countdown clock but no launch info. (Searching for "launch milestone" on a spaceflight forum returns quite a few results!)
Any ideas?
Try: http://spaceflightnow.com/shuttle/sts135/fdf/135ascent.html
Note that the times may not be exact to the second --- the precise launch window depends on recent updates of the station's position, and they target the center of the window. Although, this version says updated 8 July, so it should be about on the money.
-Alex
Also, the abort boundary calls are made in real-time by Mission Control based on performance and other factors.
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#2033
by
Mark Dave
on 08 Jul, 2011 20:01
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with the shuttle fleet retiring, what becomes of the one remaining ET-94 left in Michoud? Will it be scrapped or put in an exhibit with Atlantis or the other orbiters?
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#2034
by
iskyfly
on 09 Jul, 2011 18:48
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Watching the STS-135 replays, about 8 seconds after SRB sep and just prior to OMS ignition that if you use the background of the earth as a reference you can see what appears to be a tail left / nose right yaw. Why is this?
Next- just after the roll program there always seems to a be slight roll back in the opposite direction. Is this because of the enormous forces involved in the roll that there will always be a need for a correction back?
Finally, I have noticed the following on prior launches, including this one; During ascent, if you use the shadows cast on the stack or the Earth as reference you will notice what appears to be slight rolling back and forth around the vertical axis. What causes this?
Thank you!
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#2035
by
mtakala24
on 09 Jul, 2011 19:18
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Watching the STS-135 replays, about 8 seconds after SRB sep and just prior to OMS ignition that if you use the background of the earth as a reference you can see what appears to be a tail left / nose right yaw. Why is this?
Quidance is open-loop during SRB firing (first stage) - that means that the flying follows a preset profile, not taking realtime things, such as performance variations, into account. Soon after separation, the computers calculate what needs to be done to achieve the pinpoint orbital targets, and actively start steering the shuttle there.
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#2036
by
Lee Jay
on 10 Jul, 2011 01:24
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How much does a couple minute hold like we had on 135 affect the OMS 2 and NC burns?
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#2037
by
sdsds
on 10 Jul, 2011 18:51
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How much does a couple minute hold like we had on 135 affect the OMS 2 and NC burns?
Compare the values psloss provides to the preliminary values in the attachment to his post. Non-trivial difference!
NC-4 burn updates:
Weight: 248252 lbs
TIG: 01/19:26:23.4 --> 10:55:27 GMT / 5:55:27 Central
TGT PEG7:
dVx: +143.9 (fps)
dVy: 0
dVz: +7.6
Lots of questions about that preliminary "PAD", BTW, like almost all the acronyms. The math for {delta}VTOT is clear: sqrt((139^2) + (38.4^2)) = 144.2. TGO must be burn duration? But what are R, P, and Y for BURN ATT? And TGT HA and HP?
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#2038
by
ChrisGebhardt
on 11 Jul, 2011 00:04
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1) Watching the STS-135 replays, about 8 seconds after SRB sep and just prior to OMS ignition that if you use the background of the earth as a reference you can see what appears to be a tail left / nose right yaw. Why is this?
2) Next- just after the roll program there always seems to a be slight roll back in the opposite direction. Is this because of the enormous forces involved in the roll that there will always be a need for a correction back?
3) Finally, I have noticed the following on prior launches, including this one; During ascent, if you use the shadows cast on the stack or the Earth as reference you will notice what appears to be slight rolling back and forth around the vertical axis. What causes this?
Thank you!
1) Approximately 10 seconds prior to SRB separation, the Flight Computers initiate an "attitude hold" command to the SSMEs to hold the SSV stack in a 'rock-solid' attitude for SRB separation. When the SRBs separate, dispersions are induced onto the ET/Orbiter pair, changing their attitude ever-so-slightly. About 5 secs after SRB sep, the Flight Computers command the guidance programs to converge. This dampens out - or corrects - those attitude dispersions induced at SRB sep as well as begin to align the vehicle precisely with the mission's MECO targets.
2) Basically, yes.
3) If you are referring to the movement of shadows during SRB powered flight, the slight movement of the SSV stack is caused by aerodynamic and atmospheric forces (i.e. upper level winds) acting on the vehicle as it ascends through the dense lower atmosphere of Earth and the Thrust Vector Control system on the SRBs and the guidance system gimbaling of the SSMEs to correct the vehicle's attitude as it encounters these forces.
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#2039
by
Jorge
on 11 Jul, 2011 04:44
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How much does a couple minute hold like we had on 135 affect the OMS 2 and NC burns?
Compare the values psloss provides to the preliminary values in the attachment to his post. Non-trivial difference!
NC-4 burn updates:
Weight: 248252 lbs
TIG: 01/19:26:23.4 --> 10:55:27 GMT / 5:55:27 Central
TGT PEG7:
dVx: +143.9 (fps)
dVy: 0
dVz: +7.6
Lots of questions about that preliminary "PAD", BTW, like almost all the acronyms. The math for {delta}VTOT is clear: sqrt((139^2) + (38.4^2)) = 144.2.
In this case, yes, because dVy was zero.
TGO must be burn duration?
Correct.
But what are R, P, and Y for BURN ATT?
Roll, pitch, and yaw in inertial M50 coordinates.
And TGT HA and HP?
Target height of apogee and perigee, in nautical miles.
