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#360
by
Chris Bergin
on 08 Dec, 2007 01:12
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Wayne Hale underwear manifest reference
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#361
by
psloss
on 08 Dec, 2007 01:13
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Mike Leinbach notes that the LH2 top off completed a few hours ago; can support Sunday and Monday attempts. After that 72-hour recycle to top both cyro quantities.
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#362
by
triddirt
on 08 Dec, 2007 01:14
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Nice reference to Wayne Hales clothing packing strategy :-) (Search for WHUM)
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#363
by
psloss
on 08 Dec, 2007 01:14
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The shortened launch window would be on the order of about one minute beginning at the in-plane time.
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#364
by
psloss
on 08 Dec, 2007 01:15
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As seen on some of the screencaps, they are holding at T-11, will extend for another 24 hours.
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#365
by
Falcon
on 08 Dec, 2007 01:16
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Mike Leinbach just said the new flight rules require all 4 of the ECO sensors to be working. So if they try to launch Sunday and there are any problems with the ECO sensors, it'll be a scrub.
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#366
by
psloss
on 08 Dec, 2007 01:17
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Falcon - 7/12/2007 9:16 PM
Mike Leinbach just said the new flight rules require all 4 of the ECO sensors to be working. So if they try to launch Sunday and there are any problems with the ECO sensors, it'll be a scrub.
Yes, that was part of the proposal that Wayne Hale mentioned came from the Flight Crew Office (FCOD).
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#367
by
Ford Mustang
on 08 Dec, 2007 01:20
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Marcia Dunn had a good question about flying with 2 ECO sensors.
Hale says "Going to 2 of 4 is not where we want to be.."
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#368
by
psloss
on 08 Dec, 2007 01:21
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The logic behind going back to 4 of 4 is the tanking history (no failed WET channels during retanking).
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#369
by
psloss
on 08 Dec, 2007 01:28
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The FCOD proposal would be to allow the voltage readings to be used as a part of the decision-making during ascent.
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#370
by
psloss
on 08 Dec, 2007 01:32
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Wayne Hale answering Bill Harwood's question now doing a shortened version of ECOs 101. (Now talking about the arming mass noted in this thread earlier.)
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#371
by
psloss
on 08 Dec, 2007 01:33
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Another nice description from Wayne Hale about the orbiter software logic after reaching the arming mass.
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#372
by
ArielGold
on 08 Dec, 2007 01:35
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Just to expand on psloss' explanation of 4/4, for those who may not have seen the briefing: Hale explained that they have decided to require all four ECO sensors, because evidence shows that when this has happened in the past, all four ECO sensors worked nominally during re-tanking in the subsequent attempt. So, if all four work nominally when they go for the next attempt, that tells them that it is a (so far) consistent off-nominal issue that acts the same in every situation. If less than 4/4 function, this tells them it is not necessarily the same issue, and would require them to evaluate it differently. For instance, Hale said the sensors have never "failed dry", so if they were to see something like that, this would alert them that it was something different from what has been seen in the past. Hope that helps explain it to those who may not be as technically knowledgeable.
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#373
by
psloss
on 08 Dec, 2007 01:41
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Thanks for elaborating...just to be clear, Wayne Hale said that they are still evaluating the FCOD proposal and will decide on whether to accept it tomorrow.
Basically, if the proposal is accepted and any of the LH2 ECO circuits fail (WET or DRY) during the next tanking, they would be no-go.
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#374
by
psloss
on 08 Dec, 2007 01:45
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Briefing completed.
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#375
by
Ford Mustang
on 08 Dec, 2007 01:46
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Press conference after tomorrow's MMT meeting at 1.
Tanking will start at 5:55 AM EST on Sunday, if they do decide to go with a Sunday launch.
Intermittent updates on tanking will be before launch coverage, barring they go with Sunday.
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#376
by
dember
on 08 Dec, 2007 01:47
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Good Plan! I'm comfortable with it.
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#377
by
nsf-rt
on 08 Dec, 2007 01:54
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Someone at the briefing did ask about when during the count down 4/4 sensors had to be working. I didn't think the answer was clear. Is it the case that if one sensor behaves unexpectedly at any point that day's tanking and subsequent launch attempt will be scrubbed, or are they looking just for 4/4 to be working at the point they commit to launch? (As I write this I can see psloss has interpreted the briefing as any sensor failure during tanking will result in a scrub. )
Another question arising from the briefing is where does the output of the new "voltmeter" readings coming out of these sensors get routed to - do the crew have access to these live during ascent, are they fed into the computers, or are they read by people on the ground?
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#378
by
ETEE
on 08 Dec, 2007 01:54
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This is a very good plan and I have every confidence in Mr Hale. I also understood that there has to be a 4/4 no fault sensor flight rule in order to launch. The extra telemetry from the additional circuits would be used if sensors failed after launch.
On the sensor system, it seems strange to me that an open circuit wiring fault on the ECO sensors is designed as a fail to wet. Surely it would be better and safer if an o/c fault failed to dry?
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#379
by
TJL
on 08 Dec, 2007 01:55
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What time is T-0 on Sunday attempt?
