SpaceBanter.com - View Single Post - NASA Astronaut on Columbia Repair (and others)

**Jorge R. Frank** · November 15th 06, 11:32 PM posted to sci.space.shuttle,sci.space.history

wrote in
:

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.

Yes, I know that, and I never claimed otherwise. I *said* the results
were released *with* the CAIB report.

"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"

That's about all they could do, under the time constraints required by
the CAIB.

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.

What data are you basing that doubt on? As a matter of fact, you're
wrong. A 15-minute arcjet test on an RCC specimen with a 0.03" crack had
to be aborted a little after the five minute mark because the specimen
was eroding so 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.

My source was a presentation on RCC arcjet test results given to the
Orbiter Return-To-Flight Working Group, sometime in the spring of 2004.

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

There was no evidence *remaining*. The RCC panel in question eroded away
quickly; *none* of its lower surface was recovered. Likewise the lower
surface of the wing behind it. The CAIB noted there was very little
debris recovered from the left wing.

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.

It depends on where the damage is.

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

The earliest of those BL trips was around Mach 19, more than halfway
through the peak heating period. I'm talking about a BL that goes
turbulent from the *very beginning*, at Mach 25.

--
JRF

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