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#80 by dember on 09 Dec, 2007 04:15
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Could NASA still extend this mission two extra days? I'm doubting since they'll be cutting it close to Christmas.
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#81 by makims on 09 Dec, 2007 04:22
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Yes. They can even when launch will be delayed to Dec 13.
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#82 by punkboi on 09 Dec, 2007 04:38
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Quote
dember - 8/12/2007 9:15 PM Could NASA still extend this mission two extra days? I'm doubting since they'll be cutting it close to Christmas.
One of the reasons why the RSS was rolled back to enclose Atlantis on Thursday was to top-off the fuel cells (the liquid hydrogen, to be exact)...so NASA could maintain the two-day extension
And it's New Years Day that NASA is wary of...because of the YERO computer issue, among other things
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#83 by dember on 09 Dec, 2007 05:17
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They had that same problem with STS-116.
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#84 by lsullivan411 on 09 Dec, 2007 07:50
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Looks like maybe a damaged Tyvek cover, or is this just shadow?
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#85 by hey you on 09 Dec, 2007 07:55
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The last ECO sensor comments on this thread apparently were posted several hours ago. However,
some thoughts have occurred to me during the night and I have clipped and posted them below:
------------------------------------------------------------------------------------------------------------------------------------------------------------
Following much of the discussion related to the ECO sensors, several thoughts have surfaced.
First, for background, I do not have L2 info which limits the basis for these comments.
A partial list of concerns follows. [Note: the ordering is not in order of importance.]
The ECO sensor problem is clustered among tanks of relatively recent production. Hence,
tossing reliability numbers around using the total number of tanks ( >100 ) seems to
be improper use of statistics.
There have been less than 300 flights. 3 sigma numbers that are talked about means
approximately (notice I wrote approximately) 1 item in 300 can be outside the limits
and a 3 sigma limit can still be met. That is in the vicinity of 99.7 percent likely
to work. (Somewhere, I thought I saw a claim that 3 sigma was grounds to claim
99.95 percent reliability -- ie., 1 chance in 2000 of failure. I could be wrong, but
it seems to me that it may have been posted somewhere on these threads -- it may have
even been someone merely quoting someone else from off thread -- the point is that
3 sigma -- even widely promulgated by some -- is not failsafe, especially when an
activity consists of a chain of events totally far more than 300.)
The total time over which the sensors have had the opportunity to "malfunction" (?) during
ground tests over recent flights is large (tanks are fueled for hours measured from
start of fast fill to liftoff). Total vehicle flight time with "suspect" sensors is probably
less than an hour. The odds favor no anomalous behavior (so far) during flight time
but rather while on the ground. (An alternate explanation that a root cause might
identify is that the problem can only occur on the ground and in fact is impossible
following liftoff, which includes removing all ground support equipment at the pad
from the equation and, presumably, many of the computers at the launch complex.)
Since erratic sensor behavior is a distinct possibility, it can/should no longer be
considered a failure if sensors act erratically during the ride uphill. What is the
minimum number of failures that might provide *momentary* loss of comm? If the answer is
one, and it takes time to switch to backup equipment or a backup link, the "now
non-failure within family erratic behavior" of the ECO sensors with a comm dropout
leaves the shuttle in a "coin toss' situation relative to shutting down engines or not.
What will/does the cue card indicate for this?
From the viewpoint of a control system, how much time is there from a valid indication
during flight of an ECO sensor switching state and the crew having to take action (flip
a switch or whatever) in an irrevocable manner - shutdown one or more engines? What is
the round trip time delay for comm -- each viable path (ground tracking station vs TDRSS)
and for commanding from Mission Control? (Any satellite links? Any delays from capcom
to and from the "back rooms"?)
Now for a few thoughts of "deja vu all over again" (apparently a Yogi Berra-ism):
The SRB O-ring seals repeatedly had problems (or was that normal behavior, based
on the analysis in that time frame?). A condition that was outside the then current
flight experience (cold weather) plus, perhaps, the need for (or could that part
be omitted) a significant wind shear on ascent led to the Rogers Commission. (Richard
Feynman certainly issued an "interesting" minority report as an appendix.)
The foam falling off the shuttle was downgraded to nothing more than a source of
maintenance work. It seems that an out-of-family piece of that same foam lead to
the CAIB.
Speaking of the CAIB, some interesting comments relating to power point presentation
were made that were not particularly complimentary when the objective is to get to
the bottom of things -- hmmm, an inadvertent pun considering where some of the ECO
sensors are located. Why mention that here? Perhaps with L2 (which I do not have),
my viewpoint would be different. However, based on what information I do have,
this current situation is too reminiscent of the situation that led to CAIB and
to the Rogers Commission. (Management hat vs Engineering hat -- anybody mind if
I wear a helmet instead?)
If the new "instrumentation on instrumentation" is providing sufficiently timely and
accurate information, take the time to "hardwire" it or "firmly" patch it into the
onboard software so that the crew can take appropriate action. Forget about
the schedule. A recent action, referred to as good news on this site, seems to indicate
that flight past the Sept 30, 2010, date is plausible. It is hard to believe that if
a good-faith effort to meet that date were to still result in a 1 or 2 month slippage past it
(which would also mean that the current 6 month or so pad following March, 2010, would have
also have been used), that the Congress would not provide a one-time incremental funding
On the other hand, was it Gen. Eisenhower that said he would rather have someone under his command
that was lucky than good? Thinking that through, hopefully, at a minimum, good luck rides with the crew
and preferrably both good luck and good decisions whenever the actual launch occurs.
------------------------------------------------------------------------------------------------------------------------------
Enough lost sleep for me -- back to sleep for a few hours.
Just my thoughts. -
#86 by Wisi on 09 Dec, 2007 08:27
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Errr... as I'm not that goot at statistics I have a rather simple question:
where has the countdown clock in NASA-Web 5.0 gone??
I miss it! -
#87 by MKremer on 09 Dec, 2007 08:31
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Quote
lsullivan411 - 9/12/2007 2:50 AM
Looks like maybe a damaged Tyvek cover, or is this just shadow?
Looks like its little 'parachute' may be flapping in the breeze a bit.
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#88 by MKremer on 09 Dec, 2007 08:33
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Quote
Wisi - 9/12/2007 3:27 AM
Errr... as I'm not that goot at statistics I have a rather simple question:
where has the countdown clock in NASA-Web 5.0 gone??
I miss it!
This one?
http://countdown.ksc.nasa.gov/shuttle/countdown/cdt/
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#89 by Wisi on 09 Dec, 2007 08:37
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Quote
MKremer - 9/12/2007 10:33 AM
QuoteWisi - 9/12/2007 3:27 AM
Errr... as I'm not that goot at statistics I have a rather simple question:
where has the countdown clock in NASA-Web 5.0 gone??
I miss it!
This one?
http://countdown.ksc.nasa.gov/shuttle/countdown/cdt/
No, the small Flash-Clock that could be found via the Shuttle-Main-Page on the old NASA-Website. But this one works to. Is it up to date? As per http://spaceflightnow.com/shuttle/sts122/status.html we should be already in the T-6 hours hold... but the clock shows T-6hrs 17mins -
#90 by lsullivan411 on 09 Dec, 2007 08:50
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Quote
MKremer - 9/12/2007 4:31 AM
Quotelsullivan411 - 9/12/2007 2:50 AM
Looks like maybe a damaged Tyvek cover, or is this just shadow?
Looks like its little 'parachute' may be flapping in the breeze a bit.
Thanks - was watching a little longer and starting to think that's what it might be.
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#91 by punkboi on 09 Dec, 2007 08:53
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Wisi - 9/12/2007 1:27 AM Errr... as I'm not that goot at statistics I have a rather simple question: where has the countdown clock in NASA-Web 5.0 gone?? I miss it!
The webmaster for NASA.gov probably has little confidence that Atlantis will launch today that he/she didn't feel like updating the countdown clock on the page :bleh:
PS: The Tyvek covers on the shuttle look fine.
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#92 by dember on 09 Dec, 2007 08:58
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One hour til tanking begins.
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#93 by Chris Bergin on 09 Dec, 2007 09:29
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Go for tanking expected soon.
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#94 by Chris Bergin on 09 Dec, 2007 09:30
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#95 by Chris Bergin on 09 Dec, 2007 09:39
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15 minutes to tanking, which will begin with chilldown, then slow fill.
Fast fill follows, and then we'll start to be in the area of watching the ECO readings. -
#96 by Chris Bergin on 09 Dec, 2007 09:48
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About an hour before the first SIM command which is when the ECO readings went bad last time out.
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#97 by dember on 09 Dec, 2007 09:49
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Is nasa tv coverage still scheduled to start at 6:00?
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#98 by Chris Bergin on 09 Dec, 2007 09:51
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dember - 9/12/2007 10:49 AM
Is nasa tv coverage still scheduled to start at 6:00?
Probably.
Remember everyone, this is a live update thread. No posts unless it is an update on status. -
#99 by psloss on 09 Dec, 2007 09:51
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dember - 9/12/2007 5:49 AM
Yes, since essentially nothing has changed.
Is nasa tv coverage still scheduled to start at 6:00?
If there's a schedule, it's only likely to be pre-empted by a change. If a TV event says "no earlier than," that means they aren't sure when it's going to start.