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#180
by
Chris Bergin
on 18 Dec, 2007 12:30
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psloss - 18/12/2007 1:28 PM
As noted, the open circuit failure is what they wanted for doing the troubleshooting after stable replenish. And perhaps the intermittent behavior on other circuits, if it remains that way, will provide some additional contrast...
I'm repeating you
but ironically, this is probably the perfect scenario. One hard fail and two intermittent issues to carry out tests on
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#181
by
Chris Bergin
on 18 Dec, 2007 12:33
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I say this is good, but going on the flight rationale document, this is heading into the "offload some payload" area.
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#182
by
dotdk
on 18 Dec, 2007 12:36
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Chris Bergin - 17/12/2007 2:33 PM
I say this is good, but going on the flight rationale document, this is heading into the "offload some payload" area.
As long as that payload isn't Columbus it will be ok
Unless they can actually find the problem and fix it.
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#183
by
DaveS
on 18 Dec, 2007 12:36
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Chris Bergin - 18/12/2007 2:33 PM
I say this is good, but going on the flight rationale document, this is heading into the "offload some payload" area.
Not if they find the fault and it's fixeable out at the pad. Then they're efforst is going to focused on fixing the problem once and for all!
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#184
by
Chris Bergin
on 18 Dec, 2007 12:39
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DaveS - 18/12/2007 1:36 PM
Chris Bergin - 18/12/2007 2:33 PM
I say this is good, but going on the flight rationale document, this is heading into the "offload some payload" area.
Not if they find the fault and it's fixeable out at the pad. Then they're efforst is going to focused on fixing the problem once and for all!
Kinda going on the "New Failure (sensor other than #3 fails) During Tanking Test" with TDR positive and negative Flight Rationale. Both have payload offload.
However, both rationale notes required "All other sensor circuits function during tanking test." - and we're in a grey area with #2 and #3 right now.
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#185
by
Chris Bergin
on 18 Dec, 2007 12:44
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I'm thinking we're closest to this right now....but I'm open to other translations:
"STS-122 Flight Rationale: Assume ECO sensor system will not properly operate
during flight. Launch in plane to mitigate the probability of requiring the ECO
system. Off load payload to further mitigate the probability of requiring the ECO
system. Use the voltage measurement flight rule to mitigate the outcome of requiring
the ECO system when it is not working. Leave ECO system operational during flight
since it may provide some protection and failed dry failures have not been
experienced."
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#186
by
psloss
on 18 Dec, 2007 12:49
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Chris Bergin - 18/12/2007 8:44 AM
I'm thinking we're closest to this right now....but I'm open to other translations:
I would agree, but I'm also open to the possibility that there may be more to come out of this test and that it may affect how they go forward, short and long term.
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#187
by
Donna Spaceships
on 18 Dec, 2007 13:09
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Didn't I read that they've never even used these sensors for turning off the engines before? What would happen if they didn't work and the engines weren't turned off? Wouldn't they stop anyway when the run out of propellant?
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#188
by
Chris Bergin
on 18 Dec, 2007 13:11
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Donna Spaceships - 18/12/2007 2:09 PM
Didn't I read that they've never even used these sensors for turning off the engines before? What would happen if they didn't work and the engines weren't turned off? Wouldn't they stop anyway when the run out of propellant?
Never used before on LH2, yes. They got to within 1.5 seconds on one flight I believe.
The risk is the engines running out of LH2. If that happened, it would be loss of vehicle and crew in a rather nasty scenario of fire/explosion/over spinning turbines ripping up the vehicle etc.
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#189
by
psloss
on 18 Dec, 2007 13:12
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About an hour left to fill the tanks. LO2 about half-full; LH2 about 2/3rds full...
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#190
by
psloss
on 18 Dec, 2007 13:31
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Into topping on the LH2; LO2 about 2/3rds full...
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#191
by
psloss
on 18 Dec, 2007 13:33
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Based on today's signatures, if I heard George Diller correctly they are going to focus the TDR testing on the "intermittent" circuits, #2 and #3.
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#192
by
psloss
on 18 Dec, 2007 13:36
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The final inspection team will also be going to the pad when stable replenish is reached, as they normally do during launch countdown tankings.
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#193
by
psloss
on 18 Dec, 2007 13:50
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LH2 tank is in stable replenish; LO2 still in fast fill, about 80% full. About another 25-30 minutes before it enters stable replenish.
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#194
by
psloss
on 18 Dec, 2007 14:02
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The clock has reached T-3 hours and holding, where it will remain indefinitely...still filling the LO2 tank.
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#195
by
psloss
on 18 Dec, 2007 14:03
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Current forecast is that draining of the tank would be around 1 pm local...
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#196
by
psloss
on 18 Dec, 2007 14:11
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LO2 filling stopped unexpectedly...the pumps went offline...going to be troubleshooting...
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#197
by
psloss
on 18 Dec, 2007 14:15
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George Diller back...says the problem with the LO2 pump appears to be a blown fuse; switching to a backup pump and puts them back about an hour on the timeline. (If I heard correctly.)
Edit: estimate is 45-60 minutes back on the timeline.
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#198
by
Chris Bergin
on 18 Dec, 2007 14:16
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If I heard Diller correctly, they will lose the 45 minutes plus on troubleshooting to move to back up pump on LOX fill. Blown fuse on the primary pump...or as Philip said above
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#199
by
psloss
on 18 Dec, 2007 14:21
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Latest estimate is 30 minutes to get the backup LOX pump working...
but ironically, this is probably the perfect scenario. One hard fail and two intermittent issues to carry out tests on 