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#320
by
shuttlefan
on 21 Dec, 2007 14:51
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psloss - 21/12/2007 8:27 AM
Mike_1179 - 21/12/2007 9:16 AM
I suppose the rationale is they have more confidence in the LOX LLCO system (it functioned on STS-93)
Not sure how it factors into the rationale, but yes the LOX level sensor system has not had the type of issues that the LH2 system has. (The LOX low-level cutoff system also triggered MECO on 51-F and 78.)
STS-78? I wasn't aware of that. Obviously the cutoff must have been only a second or less early, because nothing was said about it at the time, but can you shed more light on it? Thanks in advance!
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#321
by
Chris Bergin
on 21 Dec, 2007 15:12
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Latest:
Taken from about five presentations, includes image of the location they will be removing the foam from and a clip of one of the 20 or something images of connector testing (fascinating).
http://www.nasaspaceflight.com/content/?cid=5314
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#322
by
GLS
on 21 Dec, 2007 16:15
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shuttlefan - 21/12/2007 3:51 PM
psloss - 21/12/2007 8:27 AM
Mike_1179 - 21/12/2007 9:16 AM
I suppose the rationale is they have more confidence in the LOX LLCO system (it functioned on STS-93)
Not sure how it factors into the rationale, but yes the LOX level sensor system has not had the type of issues that the LH2 system has. (The LOX low-level cutoff system also triggered MECO on 51-F and 78.)
STS-78? I wasn't aware of that. Obviously the cutoff must have been only a second or less early, because nothing was said about it at the time, but can you shed more light on it? Thanks in advance!
According to an earlier article, STS 78 was almost running out of LH2... it didn't....
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#323
by
nathan.moeller
on 21 Dec, 2007 17:07
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GLS - 21/12/2007 11:15 AM
shuttlefan - 21/12/2007 3:51 PM
psloss - 21/12/2007 8:27 AM
Mike_1179 - 21/12/2007 9:16 AM
I suppose the rationale is they have more confidence in the LOX LLCO system (it functioned on STS-93)
Not sure how it factors into the rationale, but yes the LOX level sensor system has not had the type of issues that the LH2 system has. (The LOX low-level cutoff system also triggered MECO on 51-F and 78.)
STS-78? I wasn't aware of that. Obviously the cutoff must have been only a second or less early, because nothing was said about it at the time, but can you shed more light on it? Thanks in advance!
According to an earlier article, STS 78 was almost running out of LH2... it didn't....
They've had three LOX low-level cutoffs in the history of the program, but zero LH2 low-level cutoffs.
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#324
by
Jason Davies
on 21 Dec, 2007 17:19
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nathan.moeller - 21/12/2007 12:07 PM
GLS - 21/12/2007 11:15 AM
shuttlefan - 21/12/2007 3:51 PM
psloss - 21/12/2007 8:27 AM
Mike_1179 - 21/12/2007 9:16 AM
I suppose the rationale is they have more confidence in the LOX LLCO system (it functioned on STS-93)
Not sure how it factors into the rationale, but yes the LOX level sensor system has not had the type of issues that the LH2 system has. (The LOX low-level cutoff system also triggered MECO on 51-F and 78.)
STS-78? I wasn't aware of that. Obviously the cutoff must have been only a second or less early, because nothing was said about it at the time, but can you shed more light on it? Thanks in advance!
According to an earlier article, STS 78 was almost running out of LH2... it didn't....
They've had three LOX low-level cutoffs in the history of the program, but zero LH2 low-level cutoffs.
Time to link the video of the STS-93 event!
http://forum.nasaspaceflight.com/forums/thread-view.asp?tid=11065&start=271
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#325
by
Flightstar
on 21 Dec, 2007 19:31
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Chris Bergin - 21/12/2007 6:49 AM
Lee Jay - 21/12/2007 1:00 AM
uko - 20/12/2007 3:02 PM
Can you please explain what is "fuel bias"?
Making the probability of running out of LOX different than the probability of running out of LH2 (LOX higher, LH2 lower, in this case).
There's a possibility that I don't truly understand this, but I'm sure someone will come along and correct me if I'm wrong. There's one heck of a presentation on this on L2 right now. It's a beauty, and written in terms most people could understand.
Thanks Lee, I missed the question....and I will be looking at writing up those presentations up at some point, as they are fascinating.
Going to round up the ET evaluations as of where things stand today, first.
You should write it up. Norm Knight has achieved a great overview of the dilemma involved.
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#326
by
psloss
on 21 Dec, 2007 19:38
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#327
by
stockman
on 21 Dec, 2007 19:41
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With regards to the re-foaming after repair, am I correct in assuming that we are in a non lethal area of the tank - ie, any possible sheading of foam from this low in the tank would most likely miss the orbiter (as opposed to shedding higher up the tank).
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#328
by
Chris Bergin
on 21 Dec, 2007 19:45
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#329
by
Chris Bergin
on 21 Dec, 2007 21:22
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Flightstar - 21/12/2007 8:31 PM
Chris Bergin - 21/12/2007 6:49 AM
Lee Jay - 21/12/2007 1:00 AM
uko - 20/12/2007 3:02 PM
Can you please explain what is "fuel bias"?
Making the probability of running out of LOX different than the probability of running out of LH2 (LOX higher, LH2 lower, in this case).
There's a possibility that I don't truly understand this, but I'm sure someone will come along and correct me if I'm wrong. There's one heck of a presentation on this on L2 right now. It's a beauty, and written in terms most people could understand.
Thanks Lee, I missed the question....and I will be looking at writing up those presentations up at some point, as they are fascinating.
Going to round up the ET evaluations as of where things stand today, first.
You should write it up. Norm Knight has achieved a great overview of the dilemma involved.
I will.
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#330
by
Chris Bergin
on 21 Dec, 2007 22:59
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Bill Harwood's bagged an interview with Wayne Hale.
http://www.cbsnews.com/network/news/space/current.htmlNow, as he's written, and the same for us, a plan has not been decided on. However, there's an interesting insight that one can only get from a one-on-one interview, and that's Mr Hale's apparent preference to soldering the pins (thus keeping them in place, stopping the open circuit - in theory, as cryopumping is possibly affecting the connection of the pins in the socket/connector).
Looking at the L2 presentation on associated timelines with associated repair options, soldering the external plug places the estimated repair timeline as NET Jan. 25. Soldering both external and internal plugs puts the repair timeline at NET Feb. 15.
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#331
by
Lee Jay
on 21 Dec, 2007 23:38
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Chris Bergin - 21/12/2007 4:59 PM
Bill Harwood's bagged an interview with Wayne Hale.
http://www.cbsnews.com/network/news/space/current.html
Now, as he's written, and the same for us, a plan has not been decided on. However, there's an interesting insight that one can only get from a one-on-one interview, and that's Mr Hale's apparent preference to soldering the pins (thus keeping them in place, stopping the open circuit - in theory, as cryopumping is possibly affecting the connection of the pins in the socket/connector).
Looking at the L2 presentation on associated timelines with associated repair options, soldering the external plug places the estimated repair timeline as NET Jan. 25. Soldering both external and internal plugs puts the repair timeline at NET Feb. 15.
Are these pins/sockets much different than standard mil-spec pin/socket quick disconnect connectors? They look about the same.
If they are the same, I'd have a very hard time imaging the cryo temps or cryo pumping separating the wire from the pin/socket crimp. That's a very effective crimp that comes from four directions (usually) and plastically deforms both the pin/socket and the wire. I don't see how soldering the wires into the pins/sockets would help much.
On the other hand the pin/socket connection is very weak by comparison to keep insertion forces low. I could completely imagine that contact separating from cryo temperatures and/or cryo pumping.
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#332
by
SimonShuttle
on 22 Dec, 2007 11:21
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Chris Bergin - 21/12/2007 5:59 PM
Bill Harwood's bagged an interview with Wayne Hale.
http://www.cbsnews.com/network/news/space/current.html
Now, as he's written, and the same for us, a plan has not been decided on. However, there's an interesting insight that one can only get from a one-on-one interview, and that's Mr Hale's apparent preference to soldering the pins (thus keeping them in place, stopping the open circuit - in theory, as cryopumping is possibly affecting the connection of the pins in the socket/connector).
Looking at the L2 presentation on associated timelines with associated repair options, soldering the external plug places the estimated repair timeline as NET Jan. 25. Soldering both external and internal plugs puts the repair timeline at NET Feb. 15.
Yeah, just been looking at the soldering options on the repair timeline doc. Looks like it'll push everything one flight to the right, with STS-122 going into STS-123's window. Not sure how that is a "quick fix"?
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#333
by
psloss
on 22 Dec, 2007 12:15
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SimonShuttle - 22/12/2007 7:21 AM
Yeah, just been looking at the soldering options on the repair timeline doc. Looks like it'll push everything one flight to the right, with STS-122 going into STS-123's window. Not sure how that is a "quick fix"?
Nit: there is no "window" for 1J/A; middle February was likely where the schedules had it falling on the calendar.
They have an opportunity to launch every day, with some programmatic constraints. There's a cutout for the Increment 16/17 rotation in the middle of April and there's a cutout for beta angle in the middle of May. And actually the "cutout" for a ISS expedition crew rotation with the Soyuz is about the same duration as beta angle cutouts. (Given the fluidity of the schedules right now, I wouldn't be surprised if the ATV launch has to be "deconflicted" with something again.)
There's also the issue with one of the BGAs on S4 that the ISS program may want to do before 1E:
http://forum.nasaspaceflight.com/forums/thread-view.asp?tid=61&start=556#M226326The "window" in December was more of a "window of opportunity" to fly 1E/STS-122 before New Year's than a launch window. That "opened" almost as soon as the STS-122 hardware and GSE could support the first launch attempt and "closed" when the current beta angle cutout started -- which coincides with other programmatic-type "end of year" constraints.
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#334
by
SimonShuttle
on 22 Dec, 2007 12:48
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psloss - 22/12/2007 7:15 AM
SimonShuttle - 22/12/2007 7:21 AM
Yeah, just been looking at the soldering options on the repair timeline doc. Looks like it'll push everything one flight to the right, with STS-122 going into STS-123's window. Not sure how that is a "quick fix"?
Nit: there is no "window" for 1J/A; middle February was likely where the schedules had it falling on the calendar.
Copy that
What's the best way of speaking of a launch date range? Such as, the new STS-122 date, whatever that will be, would not be called the opening of the window, given what you said?
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#335
by
psloss
on 22 Dec, 2007 13:24
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SimonShuttle - 22/12/2007 8:48 AM
Copy that
What's the best way of speaking of a launch date range? Such as, the new STS-122 date, whatever that will be, would not be called the opening of the window, given what you said?
I'm just nitpicking. :bleh: I don't see ranges because the constraint periods are much shorter than the "non-constraint" periods. I'm sure they plan to avoid cutouts as much as is reasonable, but to me looking from the outside, long-term planning seems to diminish in relevance given the current uncertainty.
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#336
by
TJL
on 22 Dec, 2007 16:17
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#337
by
Chris Bergin
on 22 Dec, 2007 16:25
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#338
by
ItsyAndy
on 23 Dec, 2007 03:24
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TJL - 22/12/2007 6:17 PM
Anyone else here having problems opening the KSC media link...
http://mediaarchive.ksc.nasa.gov/search.cfm?cat=4
Thank you.
I've been unable to open ksc.nasa.gov for all this month, just like other people I know from Europe and north America. The problem is on their side and looks like a filtering or routing issue. I wrote to them long ago with no results so far.
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#339
by
rgerhards
on 23 Dec, 2007 10:09
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For me, the media gallery started to be defunct yesterday. I analyzed the problem from systems both in north America and Europe (I am a network guy). As it looks, they have an invalidly configured router which sends packets in loops. Maybe there is someone over here knowing whom to write to?
Thanks,
Rainer
