[AR] Columbia etc. (was Re: Valley Tech...)
- From: Henry Spencer <hspencer@xxxxxxxxxxxxx>
- To: Arocket List <arocket@xxxxxxxxxxxxx>
- Date: Fri, 27 Mar 2020 14:55:20 -0400 (EDT)
On Thu, 26 Mar 2020, ken mason wrote:
I know the official story Bill but It is common knowledge such imagery
was used in a earlier mission were tiles were dislodged from the aft end
of the orbiter, can't remember the mission but it's on record. So it
would be ludicrous that they wouldn't utilize such assets again.
Note what Bill said: yes, such imaging was done on other occasions (the
missing-tiles incident you're thinking of was probably STS-1), but this
time, the risk was thought slight and it didn't seem worth the hassles of
trying to talk the spooks into doing short-notice imaging. These weren't
*NASA* assets, remember: it meant asking for a big favor from some
difficult people.
I also remember the chatter about preparing Atlantis for a
rescue mission... Why would such discussions of a rescue take place if
no damage wasn't plausible?
The discussions took place because some people were worried, especially
early on. But a careful assessment concluded -- correctly! -- that the
falling foam couldn't plausibly do dangerous damage to the tiles. And
damage to the carbon-carbon panels was not seriously considered, partly
because nobody really understood that old, weathered carbon-carbon wasn't
nearly as durable as the freshly-made stuff. Not everybody was entirely
reassured, but you can't automatically push the panic button because of
that -- somebody has to make a judgement call.
By the way, it's by no means certain that spysat imaging -- with limited
resolution, possibly some motion blur, and probably less-than-ideal
lighting and background -- would have clearly showed a hole in a *black*
surface. Doing that imaging might simply have satisfied everyone that
there was nothing to worry about.
The real problem was that NASA shuttle ops had fallen back into the same
trap that caused Challenger: "we got away with it a few times so it must
be okay". This was not the first time there'd been falling foam, but the
matter wasn't being treated as urgent.
This was not some random aberration, but a problem built into the system,
which would have caused trouble in some other way eventually if it hadn't
that time: a fragile, semi-experimental vehicle was being treated as an
operational transport.
NASA had never been given the money and resources and time to properly
develop and test an operational transport (and in any case, NASA didn't
really know how), but NASA needed an operational transport so the Shuttle
was decreed to be one. (Hint: truly experimental vehicles carry no
people except test pilots, and no payloads except test instrumentation.)
And so, despite pious pronouncements about how it would always be an
experimental vehicle, there was constant pressure to *treat* it as an
operational transport, well understood and unlikely to have dangerous
problems. After Columbia, a fellow who'd been involved in Shuttle
development told me that on watching the Mission Control reentry video, he
was shocked at how *unconcerned* people seemed as problems developed.
They thought of it as an operational vehicle.
Oh, and despite considerable effort after Columbia was lost, the foam
problem was never fully cured: there was falling foam on most of the
post-Columbia flights too, right up to the very last.
Don't be too sure these problems have gone away -- think about SLS and
Orion. Even with Commercial Crew, there's still a major flaw in the
system: NASA is simultaneously the customer and the safety authority.
It's much better if safety assessment and approval is done by people who
*don't* have a vested interest in meeting schedules and budgets.
Henry
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