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NASA Astronaut on Columbia Repair (and others)



 
 
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  #41  
Old November 15th 06, 02:07 AM posted to sci.space.shuttle,sci.space.history
Jim Oberg[_1_]
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Posts: 440
Default NASA Astronaut on Columbia Repair (and others)


"Pat Flannery" wrote
I think the odds of this working are about 1% at best.
It still doesn't address the problem of what the EVAing astronauts are
supposed to hold onto while they are putting stuff into the hole, ....


Actually that was the least of their problems -- they would be holding onto
the PLB door, the centerline edge of which would have been positioned
within a few feet of the damaged RCC area. They could have rigged a
workable foot restraint attached to handholds along that edge.



  #42  
Old November 15th 06, 02:25 AM posted to sci.space.shuttle,sci.space.history
Terrell Miller
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Posts: 274
Default NASA Astronaut on Columbia Repair (and others)


"Pat Flannery" wrote in message
...


Had there been warning, you also bet that there wouldn't have been
anybody in the ship doing entry without helmets and gloves -- an
appalling failure of safety practices, in real life, but sadly consistent
with safety standards that had crept up on some (not all, or even most)
of the team.


Yeah, that was a real sloppy thing to do. They were getting very lax about
things, and Story Musgrave's standing reentry really set a bad example in
that regard.


the thing that still galls me about that particular Musgrave Maneuver is
that, the evening of the Columbia disaster, he was on CNN *bragging* about
doing that entry, going on and on about all the neat stuff he saw out the
window. At some point he must have seen Miles's face, or he just suddenly
realized what he was saying, because he got very serious all of a sudden,
and they cut to somebody else.

Trauma makes people do and say some very unfortunate things.

--
Terrell Miller


"Just...take...the...****ing...flower...darlin g"
Terrell's dating style according to OKCupid.com


  #43  
Old November 15th 06, 05:44 AM posted to sci.space.shuttle,sci.space.history
Scott Hedrick
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Default NASA Astronaut on Columbia Repair (and others)


"Jorge R. Frank" wrote in message
...
Normally, the boundary layer trips
to turbulent well after the period of peak heating but rough surfaces can
result in early transitions. A transition prior to Mach 21 can cause
vehicle damage and a transition prior to Mach 24 can cause loss of
vehicle. The improvised Columbia repair would likely have gone turbulent
right from the beginning of entry (Mach 25), exposing the RCC panel and
the trailing black tiles to the superheated air. Columbia's damage
occurred at just about the worst possible location since the shock from
the nose cap intersects the shock from the leading edge between RCC
panels 5 and 13, depending on Mach number.


That's what some of these boneheads don't understand- you can't just use a
spatula and smooth it by eye. It has to be smooth to an extremely fine
degree to hold off (not prevent) boundary layer separation.

I'm afraid it's not something that Real Men (tm) are going to be able to do
off the cuff hanging on the end of a robot arm.


  #44  
Old November 15th 06, 05:54 AM posted to sci.space.shuttle,sci.space.history
Lee Jay
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Default NASA Astronaut on Columbia Repair (and others)

Scott Hedrick wrote:
That's what some of these boneheads don't understand- you can't just use a
spatula and smooth it by eye. It has to be smooth to an extremely fine
degree to hold off (not prevent) boundary layer separation.


Separation or transition?

Lee Jay

  #45  
Old November 15th 06, 06:25 AM posted to sci.space.shuttle,sci.space.history
Derek Lyons
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Default NASA Astronaut on Columbia Repair (and others)

Pat Flannery wrote:

I think the odds of this working are about 1% at best.
It still doesn't address the problem of what the EVAing astronauts are
supposed to hold onto while they are putting stuff into the hole, or the
fact that bags of water will boil and explode as soon as they get
depressurized in the airlock, or water coming out of some sort of
jury-rigged hose is going to emerge as a spray of superfine droplets,
not come out as a stream that will flow into the hole.
You might be able to get the hole filled in with the hose, but it would
be anything but smooth, and you'd have chunks of ice around it that
would break free and do more damage as heating started on reentry.


Not to mention the fact that after you overcome all _those_
difficulties - you have to deal with two different (additional)
problems;

1 - hoping the steam from the vaporizing ice doesn't damage your patch
2 - your patch will also be under attack from behind as the
temperature in the wing goes above freezing.

D.
--
Touch-twice life. Eat. Drink. Laugh.

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL
  #47  
Old November 15th 06, 07:15 AM posted to sci.space.shuttle,sci.space.history
Pat Flannery
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Posts: 18,465
Default NASA Astronaut on Columbia Repair (and others)



Herb Schaltegger wrote:

That's not a real URL, Patrick.

No booze for you!



Yeah, realized that and went to the page it was on instead. :-)

Pat
  #48  
Old November 15th 06, 02:43 PM posted to sci.space.shuttle,sci.space.history
Craig Fink
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Default NASA Astronaut on Columbia Repair (and others)

Personally, I from what I've read in the CAIB, it doesn't look to me that
NASA seriously looked at the repair option before putting out the report.
Bags of water and tools, when they had all sorts of thermal blankets, some
graphite composites, and who knows what else. Having never seriously
looked at the repair option, it's no wonder NASA is has so much trouble
trying to figure out how to actually do a premission planned repair.
Really makes me wonder if the attitude at NASA went from "There is nothing
we can do, so why look" to "There is nothing we could have done anyway, we
did the right thing".

Columbia sometimes it tripped the boundary layer quite early, Mach 19.

....Normally, the transition from smooth to turbulent flow occurs equally
on both wings after the orbiter has slowed to about Mach 8. On some
missions, however, the transition has happened when the shuttle is higher,
in the hottest part of re-entry, moving as fast as Mach 19...
http://www.floridatoday.com/columbia...ry2A44731A.htm
"This is magnified when transition occurs early, which has resulted in
slumped tiles and other damage to the shuttle (tiles). The higher heating
has also aggravated the effect of ascent debris impacts."

Also, you have no idea if an improvised Columbia repair would or would not
have trip the boundary layer. Or, even if it was tripped what damage would
occur, other than a bunch of slumped tiles and possibly an overheated
unusable Vehicle sitting on the runway. Your statement about Mach 24-25
being some sort of limit makes no sense at all. From EI to Mach 25,
temperatures may be high, but density is very low. Dynamic pressure is
below 20 psf, and stagnation heat flux is still building up to this point.
It's not the high heating region.

Page 63, 64
http://caib.nasa.gov/events/public_h...8/present.html

Anybody have a good URL to all the Columbia Repair Studies? How many
different patches were studied? What materials were used in the patches?
Did they have the spacewalk consumables? How did all the candidate repair
materials do in the arc jet facility? Where are the studies? Where are the
test/experimental results? How did the thermal blankets perform on the
leading edge? Did they melt and flow smooth? Did the high spot disappear
first? What Mach Number? How did the glass/water composites perform?

Would a Thanksgiving Turkey have worked better?

In figuring out how to patch some future Orbiter, figuring out how to
patch Columbia wouldn't have been a total waste of time.

--
Craig Fink
Courtesy E-Mail Welcome @
--

On Tue, 14 Nov 2006 23:44:46-0500, Scott Hedrick wrote:

"Jorge R. Frank" wrote in message
...
Normally, the boundary layer trips
to turbulent well after the period of peak heating but rough surfaces can
result in early transitions. A transition prior to Mach 21 can cause
vehicle damage and a transition prior to Mach 24 can cause loss of
vehicle. The improvised Columbia repair would likely have gone turbulent
right from the beginning of entry (Mach 25), exposing the RCC panel and
the trailing black tiles to the superheated air. Columbia's damage
occurred at just about the worst possible location since the shock from
the nose cap intersects the shock from the leading edge between RCC
panels 5 and 13, depending on Mach number.



  #49  
Old November 15th 06, 06:45 PM posted to sci.space.shuttle,sci.space.history
[email protected]
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Default NASA Astronaut on Columbia Repair (and others)


Remember the question why NASA did not release their results on the
in orbit repair options for Columbia?

Incorrect. The results were released with the CAIB report, both as a
chapter in the main report and as an appendix.


The only "results" they released was a statement that their tests were
inconclusive. No report what they tested, how they tested neither
the results they got.


They did no materials testing, only analysis, and very limited analysis
at that. They didn't just say the analysis was inconclusive. They said
more than that.

"The assessment of the level of difficulty of the repair operation
is high. The level of risk to the crew is moderate and the risk of doing
additional damage to the Orbiter is high (i.e. enlarging the wing leading
edge breach). The overall assessment of the expectation of task success
is moderate to low, depending on damage site characteristics and the
required repair technique."

"The results while inconclusive, do not indicate this option was likely
to succeed."


Actually, what you cite above is a report by a NASA team. It was
published by the CAIB but the CAIB was not involved in its writing.
The CAIB conclusion on the subject did not oppose it because they had
no other data then the NASA report to base on:

"Because the NASA team could not verify that the repairs would survive
even a modified re-entry, the rescue option had a considerably higher
chance of bringing Columbia's crew back alive." (CAIB Vol. 1)

In effect, the same guys who immediately after the diasater openly stated
"there was no way to repair" (they even said it that line as the astronauts
were still alive) did later the task to investigate whether their statement
was correct. They did it the NASA disaster way: "inconclusive"


It seems the results were too
unwanted obvious:

Gutierrez is wrong. And it turns out, so were NASA's results from the
CAIB report. The three years of work that have gone into RCC repair
capability since that report have made clear that the in-flight
repair options for Columbia would not have worked.


What is your source? Was it you who said something the same line over
a year ago claiming some knowledge of NASA tests not yet released? As
we got no source it was dismissed as one of the many Columbia Usenet
myths. But maybe there is a report out now. I`m not the only one eager
to read it!


It depends on what you mean by "report". NASA has published no report
directly addressing Columbia repair on STS-107. But then again, that's
not necessary. What I did was to read the CAIB report, both Volume 1
section 6.4 and Appendix D.13, and make careful note of the assumptions
both stated and implicit. Then I read on NASA's work on RCC repair and
entry aerothermodynamics since the CAIB report was published. This work
does not directly address 107, but the results of it invalidate the
assumptions from CAIB. It's as simple as that.

First, the results of the RCC impact tests at SwRI demonstrate that the
area around the hole in panel 8L almost certainly had surrounding areas
where the RCC was cracked and delaminated. Arcjet tests at Ames and JSC
demonstrate that RCC damage propagates rapidly along these cracks. So it
doesn't matter what the crew puts in the hole behind the panel to try to
stop the flow of superheated air; the damage will quickly spread and
allow the superheated air to simply go around the repair.


In simple words you assume the hole in the RCC would grow up until
most the RCC was consumed and the ice block was no longer a blockade.
That would be a clear "no way to repair". But I doubt that the
delamination would spread that fast. Its a plasma oxidation of an
otherwise covered RCC layer on the open crack surface. The hole may
be 2 cm wider after reentry, but not 4 times its size. As you read
it otherwise somewhere (or you got that impression there), please
give me your source.


Second, due to the improvised materials, the repair would not have been
smooth enough to prevent an early boundary layer transition. RCC is rated
to 3000 deg F, the lower surface black tiles to 2200 deg F. The shock
ahead of the vehicle contains superheated air at temperatures up to
10,000 deg F. It is the laminar (smooth) boundary layer that protects the
TPS from these extreme temperatures. Normally, the boundary layer trips
to turbulent well after the period of peak heating but rough surfaces can
result in early transitions. A transition prior to Mach 21 can cause
vehicle damage and a transition prior to Mach 24 can cause loss of
vehicle. The improvised Columbia repair would likely have gone turbulent
right from the beginning of entry (Mach 25), exposing the RCC panel and
the trailing black tiles to the superheated air. Columbia's damage
occurred at just about the worst possible location since the shock from
the nose cap intersects the shock from the leading edge between RCC
panels 5 and 13, depending on Mach number.


We had this issue here before, maybe not with you. Just summ:

1. the hole it had is a larger BL obstacle then any remaining
irregularities from an repair

2. there was no evidence of BL trip related damage by CAIB, it
all developed at the RCC

3. required smoothness criteria for the shuttle was to protect it
against any thermal damage to the tiles. This was to keep the tiles
reusable. In case of an emergency some tile damage would be accecptable.

4. on other missions Columbia had several early BL trips without serious
damage or without any damage at all.


--
JRF



## CrossPoint v3.12d R ##
  #50  
Old November 15th 06, 07:49 PM posted to sci.space.shuttle,sci.space.history
Mary Pegg[_3_]
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Posts: 44
Default NASA Astronaut on Columbia Repair (and others)

The Guy In Ireland wrote:

"Story Musgrave's standing reentry really set a bad example in that
regard. "

Sorry whats that all about? Did he stand for a reentry and why did he?


From http://www.spacestory.com/flyingdr.htm :

"I was conducting my own experiment. The whole flight had been so totally
exhilarating and I was on such a high that I decided to stand throughout
re-entry. It's my nature to press and push, to go beyond what's expected. I
had my Hasselblad camera and I was taking some photos. Also, I wanted to
prove that you can stand while going from zero gravity back into gravity.
That's important if an astronaut ever has to leave the top deck and go
below to throw a switch or circuit breaker. I wanted to show that the
cardiovascular system doesn't have any problem going back into gravity and
that you don't have to be strapped down."

"My standing was smooth and steady, and it shows how the STS system is
maturing. We all had total confidence. Standing up throughout re-entry,
instead of being strapped down, was the perfect end to a perfect trip. I
was having fun, as always. "
--
Something like: "ntlworld" "com" "dot" "at" "marypegg"
 




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