-
#140
by
nathan.moeller
on 06 Dec, 2007 18:23
-
dember - 6/12/2007 1:21 PM
What about STS-115?
STS-115 had so many delays I honestly can't remember what happened with the ECO sensors for that flight. I think it resolved itself but someone else will have to elaborate.
-
#141
by
nathan.moeller
on 06 Dec, 2007 18:23
-
Yegor - 6/12/2007 1:22 PM
Thank you very much for quick answers! 
Our pleasure
All part of the NSF community.
-
#142
by
psloss
on 06 Dec, 2007 18:26
-
dember - 6/12/2007 2:21 PM
What about STS-115?
In that case, they followed the procedure agreed upon after STS-114, which was to detank and then retank the next day. None of the circuits failed WET on the second attempt and they launched.
This situation isn't exactly the same as two of the LH2 ECO measurements are showing this behavior; in the previous launch attempt cases, only one measurement failed WET.
-
#143
by
Zoomer30
on 06 Dec, 2007 18:37
-
I dont get how on one try the ECOs dont work and then next try they do. Seems a little odd. Such an important part needs to work 100% of the time. Running out of gas in a car is inconvinent. Running out of gas on the shuttle is deadly (the turbo pumps spin out of control).
Its like a PC. One day it acts up, you dont do anything to fix it, the next try its fine...huh? I remember thats what they did the last time the ECOs failed wet. Just try again and hope for the best.
-
#144
by
Zoomer30
on 06 Dec, 2007 18:40
-
Would be nice if there was some sort of test they could run in the VAB BEFORE they rolled out and all that to find out before that the ECOs where toast. Makes me worry about the CEV Stick and the LEV Launcher, they will probably have the same sensors!
-
#145
by
nathan.moeller
on 06 Dec, 2007 18:41
-
Zoomer30 - 6/12/2007 1:37 PM
I dont get how on one try the ECOs dont work and then next try they do. Seems a little odd. Such an important part needs to work 100% of the time. Running out of gas in a car is inconvinent. Running out of gas on the shuttle is deadly (the turbo pumps spin out of control).
Its like a PC. One day it acts up, you dont do anything to fix it, the next try its fine...huh? I remember thats what they did the last time the ECOs failed wet. Just try again and hope for the best.
It's a pretty complex little piece of equipment. And some believe the problem isn't in the sensors themselves. Some think it's related to connections between the sensors and the orbiter avionics. Very, very complex.
-
#146
by
Jim
on 06 Dec, 2007 18:46
-
Zoomer30 - 6/12/2007 2:40 PM
Would be nice if there was some sort of test they could run in the VAB BEFORE they rolled out and all that to find out before that the ECOs where toast. Makes me worry about the CEV Stick and the LEV Launcher, they will probably have the same sensors!
They won't
-
#147
by
dember
on 06 Dec, 2007 18:49
-
It would make it easier if they could run tests.
-
#148
by
Zoomer30
on 06 Dec, 2007 18:50
-
Its like a light switch that one day you hit it and the light does not come on, the next day it works fine.
That article ECO SENSORS 101 explains the issue well. Reading that makes me wonder if we should even be flying with such a touchy and important item that has an issue that just cant be explained. From that ECO 101 article it seems the sensors could fail dry and shut the engines off way early, or fail wet and run out of fuel or O2. Run out of fuel and you have a oxygen rich issue, lots of fire risk. The other way and you have turbo pump cavitation, they go from normal speed to who knows how fast in the blink of an eye and come apart.
-
#149
by
Chris Bergin
on 06 Dec, 2007 18:53
-
MMT meeting to discuss 24 hours or longer on the turnaround.
-
#150
by
psloss
on 06 Dec, 2007 18:53
-
Zoomer30 - 6/12/2007 2:50 PM
From that ECO 101 article it seems the sensors could fail dry and shut the engines off way early, or fail wet and run out of fuel or O2. Run out of fuel and you have a oxygen rich issue, lots of fire risk. The other way and you have turbo pump cavitation, they go from normal speed to who knows how fast in the blink of an eye and come apart.
That's why they have four of them on both sides.
-
#151
by
nathan.moeller
on 06 Dec, 2007 18:57
-
dember - 6/12/2007 1:49 PM
It would make it easier if they could run tests.
They do run tests. They run tests several times during the launch countdown. You have to fill the tank to truly test these things out. That way they can run simulated dry commands and make sure they're functioning properly. It won't help you much to run tests when the tank is empty. You'll be making sure they'll show 'dry' when it's really dry. But you have to make sure it'll will also show 'wet' when it's loaded. It HAS to work both ways, and the only way to try it out is by filling the tank on launch day. If it works, great. If not, find the problem, fix it and try again.
This sort of thing happens, people. This is how they've approached this sort of problem before and, just like all the others, they'll get it fixed for STS-122. Let's quit questioning/criticizing their methods and let them do their jobs. For all we know, they could try tomorrow and everything could work fine. Just sit back and enjoy the ride.
-
#152
by
nathan.moeller
on 06 Dec, 2007 18:59
-
psloss - 6/12/2007 1:53 PM
Zoomer30 - 6/12/2007 2:50 PM
From that ECO 101 article it seems the sensors could fail dry and shut the engines off way early, or fail wet and run out of fuel or O2. Run out of fuel and you have a oxygen rich issue, lots of fire risk. The other way and you have turbo pump cavitation, they go from normal speed to who knows how fast in the blink of an eye and come apart.
That's why they have four of them on both sides.
It's also why they have four instead of the required two. If something goes wrong with one, or even two, sensors, they have complete redundancy to pick up the slack.
-
#153
by
Chris Bergin
on 06 Dec, 2007 19:17
-
-
#154
by
Joffan
on 06 Dec, 2007 19:23
-
One positive here (in a back-handed kind of way) is that the SIM DRY signal identfied a real issue wth sensors #3 and #4, as evidenced by their behaviour on de-tanking.
This means to me that if the Shuttle team does decide to have another try tomorrow, and the sensors show good in the tests, we can have a high level of confidence in that result.
(ETA: I'm counting the whole signal path as part of the sensor here).
-
#155
by
marshallsplace
on 06 Dec, 2007 19:28
-
Up beanie and waiting patiently....
-
#156
by
jacqmans
on 06 Dec, 2007 19:35
-
-
#157
by
mkirk
on 06 Dec, 2007 19:35
-
It looks like the afternoon briefing is going to slip, no new time as yet (MMT is still in progress).
I am sure nobody is surprised.
Mark Kirkman
-
#158
by
kimmern123
on 06 Dec, 2007 19:55
-
Does the flight crew have any input on the final decision of whether to try again tomorrow or not?
-
#159
by
Chris Bergin
on 06 Dec, 2007 19:56
-
ECO sensors still acting strange even now. Engineers are concerned, as LH2 ECO #1 went WET for no reason within the last hour.
Really not sure how the FD is thinking this is looking good for tomorrow, but we'll see what the MMT say.
MMT on a break, about to head back in.
