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#300
by
collectSPACE
on 09 Dec, 2007 14:55
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Statement by the STS-122 crew:
We want to thank everyone who worked so hard to get us into space this launch window. We had support teams working around the clock at KSC, JSC, and numerous sites in Europe. We were ready to fly, but understand that these types of technical challenges are part of the space program. We hope everyone gets some well-deserved rest, and we will be back to try again when the vehicle is ready to fly.
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#301
by
joncz
on 09 Dec, 2007 14:57
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If they're considering putting a Time Domain Reflectometer in the circuit as part of their additional instrumentation, then they would go for another tanking test in hopes (as Leroy said) that the open circuit reoccurs. The TDR would tell them where the open circuit was.
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#302
by
mark147
on 09 Dec, 2007 15:01
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A lot of the focus of the investigations so far seems to have been on the possible effects of the LH2 and the cryogenic temperatures on the sensors and wiring. Is it possible that it's not that at all and that it is a mechanical problem that arises when you put tonnes of propellant in the tank? That could explain why they haven't been able to reproduce it anywhere else than with the complete stack at the pad. I wonder if that's the thinking behind detanking to the 5% level and waiting for a few hours - the sensors will still be covered but the weight of the tank will be less than the weight at the point that the problem occurred.
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#303
by
STS Tony
on 09 Dec, 2007 16:19
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Thanks for the thread to catch up with what happened
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#304
by
LSainsbury
on 09 Dec, 2007 17:04
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As we are now holding until Jan 08, will the stack be rolled back to the VAB?
If not - will any adverse weather affect the orbiter / ET / SRBs?
I assume if the stack stays the RSS will be rolled back for protection?
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#305
by
apollo13
on 09 Dec, 2007 17:05
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LSainsbury - 9/12/2007 1:04 PM
As we are now holding until Jan 08,
Jan. 2nd 
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#306
by
LSainsbury
on 09 Dec, 2007 17:09
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apollo13 - 9/12/2007 5:05 PM
LSainsbury - 9/12/2007 1:04 PM
As we are now holding until Jan 08,
Jan. 2nd
Yes - I know - I meant Jan 2008!!
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#307
by
Michael22090
on 09 Dec, 2007 17:10
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LSainsbury - 9/12/2007 12:04 PM
As we are now holding until Jan 08, will the stack be rolled back to the VAB?
If not - will any adverse weather affect the orbiter / ET / SRBs?
I assume if the stack stays the RSS will be rolled back for protection?
It is helpful to read back through the thread, because all of the questions have already been answered.
The new launch date is NET Jan. 2. It is not known yet if they will have to roll back. To early to tell. We will know more on Tuesday when a troubleshooting team meets with the PRCB. Also, yes the RSS should be moved back into the mate position later today.
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#308
by
Zoomer30
on 09 Dec, 2007 17:20
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So if they roll back will they just pull Atlantis and put her on a new stack? or try to replace the ECOs? At this point I would want a new tank altogether, just from the "this thing is jinxed" pov.
From my POV it would be quicker to just swap the ship out to another stack (if one is ready) than to have to root around inside the tank to get the ECOs and change them.
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#309
by
LSainsbury
on 09 Dec, 2007 17:21
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OK - will re-read the thread - thanks for that!
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#310
by
Michael22090
on 09 Dec, 2007 17:26
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Zoomer30 - 9/12/2007 12:20 PM
So if they roll back will they just pull Atlantis and put her on a new stack? or try to replace the ECOs? At this point I would want a new tank altogether, just from the "this thing is jinxed" pov.
From my POV it would be quicker to just swap the ship out to another stack (if one is ready) than to have to root around inside the tank to get the ECOs and change them.
They will have to troubleshoot everything first. It would be bad to move Atlantis to a new stack and then it turns out the problem isn't even on the ET side, but in the Orbiter's wiring. Then they would be having the same problem and would have gotten anywhere. I am sure we will know a little more on Tuesday. I am pretty confident that the folks down there at KSC will be working hard in the next few days to figure this problem out.
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#311
by
Zoomer30
on 09 Dec, 2007 17:43
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Do they have a breakdown of ECO issues per shuttle? I mean does it seem like its just one ship or is it just random? I dont know. There really needs to be a way to test these things before they waste cash putting the propellants in only to find out they dont work. I would say at this point since the issue was not the same this time (different sensors) it could be a wiring issue. Broken sensors dont fix themselves.
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#312
by
Zachstar
on 09 Dec, 2007 17:57
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Very saddening to see such a perfect lead up effort get trounced by a flawed system. However they did good work and I want to thank them.
Now that we have a chance to take a breath. Let me throw in my call to disable the entire ECO sensor system.
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#313
by
DaveS
on 09 Dec, 2007 18:00
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Zoomer30 - 9/12/2007 7:20 PM
So if they roll back will they just pull Atlantis and put her on a new stack? or try to replace the ECOs? At this point I would want a new tank altogether, just from the "this thing is jinxed" pov.
From my POV it would be quicker to just swap the ship out to another stack (if one is ready) than to have to root around inside the tank to get the ECOs and change them.
Bad and uninformed POV.
They did *exactly* this with STS-114. They hauled Discovery back to the VAB, demated her from ET-120, mated her to ET-121 rolled back out to the pad, prepped for launch.
Launch day, July 13 2005:
Prior to crew ingress a ECO sensor check was made, and guess what? LH2 ECO sensor#2 failed "WET". Launch attempt scrubbed when Stephen Robinson was being strapped in.
Spent 13 days troubleshooting the problem with no success. Although they found a very small grounding imperfecting in some wiring in Discovery which they fixed, they were never able to pinpoint it as the cause.
Now STS-115 launch attempt#2, September 8 2006:
Launch was scrubbed when LH2 ECO sensor#3 failed "WET". This despite it being changed out in the VAB to prevent this from happening.
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#314
by
Jorge
on 09 Dec, 2007 18:22
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Zoomer30 - 9/12/2007 12:43 PM
Do they have a breakdown of ECO issues per shuttle? I mean does it seem like its just one ship or is it just random? I dont know.
On L2.
There really needs to be a way to test these things before they waste cash putting the propellants in only to find out they dont work.
They "test" them all the time. The sensors behave differently at cryo temperatures so you don't really know if they work until you tank. That is the bottom line here.
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#315
by
kimmern123
on 09 Dec, 2007 18:24
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Will this delay in any way influence the ISS crew exchanges? Leo seems to get a mighty short stay if he goes up on 122 and down again on 123.
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#316
by
Integrator
on 09 Dec, 2007 18:29
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Believe it or not, cryo liquid tanks sensors is one area that could stand some technology improvement. Another is cryo mass flow, that allows determination of what part is liquid, what part is boiling. Turbine flow meters fail in this respect. Delta IV Heavy encountered this on first launch attempt and had an early shutdown, preventing attainment of desired orbit. The problem is rocket engineers are never sure exactly how much fuel and oxidizer their systems are using in flight, so they compensate for uncertainty by overtanking propellants and depend on ground test and derived measurements, such as those from these ECO sensors to determine cutoff criteria. True mass flow through the engine is unknown. Anyone with new sensor technology ideas in these areas should promote them and the various companies that produce liquid rocket engines should investigate integrating these new technologies. It's like driving a car on a long trip with no gas gage.
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#317
by
lcs
on 09 Dec, 2007 18:40
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"They "test" them all the time. The sensors behave differently at cryo temperatures so you don't really know if they work until you tank. That is the bottom line here."
Why don't they test the sensors with real cryo before putting them into the ET?
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#318
by
psloss
on 09 Dec, 2007 18:41
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lcs - 9/12/2007 2:40 PM
Why don't they test the sensors with real cryo before putting them into the ET?
Wayne Hale said they've done that.
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#319
by
ShuttleDiscovery
on 09 Dec, 2007 18:43
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kimmern123 - 9/12/2007 7:24 PM
Will this delay in any way influence the ISS crew exchanges? Leo seems to get a mighty short stay if he goes up on 122 and down again on 123.
I mentioned that way back in the thread, but no one responded. One month after so much training isn't really fair, especially as he is an ESA astronaut so he has a lower chance of flying again.
They may have Leo come down on 124, and everyone else bumped down one flight, but who knows? We'll ahve to wait and see!
