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#280 by Chris Bergin on 19 Dec, 2007 18:03
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Eight options to fix the connector issue being evaluated by NASA. Three allow for Jan 10, five do not.
http://www.nasaspaceflight.com/content/?cid=5312
There's more to come and will write up as much as possible from L2 as we go. -
#281 by Chris Bergin on 19 Dec, 2007 20:00
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Work to remove the foam for ET access (manhole) to begin this weekend.
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#282 by Stowbridge on 19 Dec, 2007 20:08
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Chris Bergin - 19/12/2007 1:03 PM
Eight options to fix the connector issue being evaluated by NASA. Three allow for Jan 10, five do not.
http://www.nasaspaceflight.com/content/?cid=5312
There's more to come and will write up as much as possible from L2 as we go.
Chris, what is that graph in the article? -
#283 by Chris Bergin on 19 Dec, 2007 20:12
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Stowbridge - 19/12/2007 9:08 PM
QuoteChris Bergin - 19/12/2007 1:03 PM
Eight options to fix the connector issue being evaluated by NASA. Three allow for Jan 10, five do not.
http://www.nasaspaceflight.com/content/?cid=5312
There's more to come and will write up as much as possible from L2 as we go.
Chris, what is that graph in the article?
A screenshot from the TDR Results presentation on L2. Here's a full size version of one of the screenshots:
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#284 by Chris Bergin on 19 Dec, 2007 20:14
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To add, that also appears to be the screen they saw in the MLP during testing. Look at where the engineer is pointing (though this is just an assumption, based on timing etc. etc.)
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#285 by shuttle_buff on 19 Dec, 2007 21:35
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This appears to be option 6, 7 or 8?
But all those options required roll back. Why would they be opening up the ET man hole cover if they did not intend to replace the internal connector unless the connector is secured from the inside and not the outside? -
#286 by on 19 Dec, 2007 21:53
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shuttle_buff - 19/12/2007 4:35 PM This appears to be option 6, 7 or 8? But all those options required roll back. Why would they be opening up the ET man hole cover if they did not intend to replace the internal connector unless the connector is secured from the inside and not the outside?
Let's not start making assumptions on here. Let the engineers and managers make the right decision. They will make the decision that is right for the program.
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#287 by ETEE on 19 Dec, 2007 22:09
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For those of us not on L2, can someone explain where this manhole is exactly. Is it an entry into the LH2 tank or the ET outer shell?
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#288 by Chris Bergin on 19 Dec, 2007 22:20
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shuttle_buff - 19/12/2007 10:35 PM
This appears to be option 6, 7 or 8?
But all those options required roll back. Why would they be opening up the ET man hole cover if they did not intend to replace the internal connector unless the connector is secured from the inside and not the outside?
We still have PRCB content coming in from today's meeting on L2. Then we'll try and round up some answers here and another article will follow tomorrow. -
#289 by Chris Bergin on 19 Dec, 2007 22:21
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ETEE - 19/12/2007 11:09 PM
For those of us not on L2, can someone explain where this manhole is exactly. Is it an entry into the LH2 tank or the ET outer shell?
You don't need L2 for that
You can see the manhole foamed up (but still obvious) on ET images of the aft, but here's a good one from the ECO work when they R&R'ed the sensors:
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#290 by MKremer on 19 Dec, 2007 22:25
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ETEE - 19/12/2007 5:09 PM
For those of us not on L2, can someone explain where this manhole is exactly. Is it an entry into the LH2 tank or the ET outer shell?
Go to the KSC Multimedia site and search for "external tank manhole". That will bring up all the pics from when ET-119 had to be entered to replace the ECO sensors.
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#291 by a_langwich on 20 Dec, 2007 00:03
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A thought about the current ECO-tension...
What about injecting a nice gel into the connector? If cryopumping is involved, displacing air with something else that will freeze and thus lock the pins in place seems useful.
The gel/grease I had in mind is the stuff used in Mil Std electrical boxes to reduce fire hazard, but of course it would depend on the thermal coefficient of expansion for that material vs the other material in the connector.
If they go with the soldering option, I suppose you could skip gel/grease and epoxy the whole thing.
It's interesting the problem goes away after the tank warms back up, most connection problems don't. On the other hand, it would have been fixed years ago if it were so cooperative. -
#292 by Jorge on 20 Dec, 2007 00:20
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ETEE - 19/12/2007 5:09 PM
For those of us not on L2, can someone explain where this manhole is exactly. Is it an entry into the LH2 tank or the ET outer shell?
What exactly do you mean by "outer shell"? -
#293 by chas on 20 Dec, 2007 01:32
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Great info on the troubleshooting of the ECO's. Any clues to why STS 120 didn't have any issues?
Luck? -
#294 by Avron on 20 Dec, 2007 04:54
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a_langwich - 19/12/2007 8:03 PM
A thought about the current ECO-tension...
What about injecting a nice gel into the connector? If cryopumping is involved, displacing air with something else that will freeze and thus lock the pins in place seems useful.
Great plan .. I like.. but how do you make sure you have
1) filled all voids
2) Not added a contaminant to reduce pin/socket connection -
#295 by rdale on 20 Dec, 2007 09:34
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chas - 19/12/2007 9:32 PM
Great info on the troubleshooting of the ECO's. Any clues to why STS 120 didn't have any issues?
Luck?
The same reason previous flights came up with no issues - it is an intermittent issue... -
#296 by montmein69 on 20 Dec, 2007 11:16
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Chris Bergin - 19/12/2007 3:00 PM
Work to remove the foam for ET access (manhole) to begin this weekend.
They have to use a clean access to open and go inside the tank. It was never done on the pad, wasn't it ?
Neither the spray of new foam ?
Any other way than a rollback in the VAB to make all that stuff ? -
#297 by Chris Bergin on 20 Dec, 2007 11:39
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montmein69 - 20/12/2007 12:16 PM
QuoteChris Bergin - 19/12/2007 3:00 PM
Work to remove the foam for ET access (manhole) to begin this weekend.
They have to use a clean access to open and go inside the tank. It was never done on the pad, wasn't it ?
Neither the spray of new foam ?
Any other way than a rollback in the VAB to make all that stuff ?
What they are doing with the manhole can be done at the pad. I believe they've even changed ECO sensors out at the pad before years ago....but we await their final plan before we'll know if it involves rollback. Currently, it does not. -
#298 by ETEE on 20 Dec, 2007 11:39
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Chris Bergin - 19/12/2007 11:21 PM
QuoteETEE - 19/12/2007 11:09 PM
For those of us not on L2, can someone explain where this manhole is exactly. Is it an entry into the LH2 tank or the ET outer shell?
You don't need L2 for that
You can see the manhole foamed up (but still obvious) on ET images of the aft, but here's a good one from the ECO work when they R&R'ed the sensors:
Thanks for the heads up! It looks like there must also be a LO2 manhole as well. -
#299 by Jim on 20 Dec, 2007 12:20
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ETEE - 19/12/2007 6:09 PM
For those of us not on L2, can someone explain where this manhole is exactly. Is it an entry into the LH2 tank or the ET outer shell?
There is no "outer shell" of the ET, the tanks are structural members. Two tanks are connected together by the intertank. The tanks are not enclosed
