Discovery's left wing STS-114

In article ,
(ed kyle) wrote:

I read the CAIB report several times. After "eliminate shedding
from ET", the No. 2 recommendation was to increase the shuttle's
ability to sustain debris damage.

That's all well and good and in principle, it's an excellent idea for
spacecraft to be damage-tolerant for entry. The biggest problem with
that recommendation vis a vis the STS orbiter is that it is an
already-existing vehicle built to meet a myriad of design
specifications and requirements. Adding a new requirement ("The
shuttle orbiter shall be capable of withstanding impacts . . . ")
which directly contradicts a basic design premise for the entire stack
("There shall be no debris shedding . . .") seriously complicates and
already-complicated situation. That's why the CAIB made
"recommendations" along these lines rather than making them hard and
firm rules for return to flight.

One of the long-term goals
was to increase the orbiter's ability to re-enter Earth's
atmosphere even with minor damage. The photos show that neither
of these "toughen up the orbiter" recommendations have been
addressed.

That's what all the various on-obit inspection and repair techniques
(which Jon and others have posted about numerous times) are designed
to address.

- Ed Kyle

--
Herb Schaltegger, B.S., J.D.
"Never underestimate the power of human stupidity."
~ Robert A. Heinlein
http://www.angryherb.net

(ed kyle) wrote:
(dave schneider) wrote:
wrote:
Two years, a few billion dollars, and it looks like they're installing
essentially the same equipment that failed before ....


Where did you get the idea that they would be installing something
different?

From the CAIB report, which, second only to eliminating
ET shedding, recommended toughening up the orbiter to
debris impacts.

Indeed, but was there a specific recommendation as to how? Was there
a time frame for that? Did it say "RTF"?

At this point, there is no other equipment that can be installed on
the WLE. Other designs (cue Kim Keller) might have a different answer
to a robust WLE, but to redesign the Shuttle WLE is a major project,
probably involving a couple of years just in the test program.

NASA has put in extra effort on the *repair* issue, and even that is
much harder to accomplish on the WLE than on the bulk tile, has added
WLE *breach detection* systems (actually, impact detection IIRC) to
help determine when the wing has been compromised, and has worked to
reduce possible impactants (cf Ramp Bipod change).

And why did you put another glass windshield in your
car/plane/boat/train when those have been shown to fail when the deer
doesn't clear the hood?

If my original windshield had been plain glass (and if I
had survived the accident), I would have learned that it
was a really good idea to upgrade to shatter-proof safety
glass.

Even Saab and Volvo will tell you that there is no such thing,
although they work hard to reduce the chance of breakage and use
special tempered glass laminates to insure that breakage produces
"popcorn" instead of shards.

If the deer is coming through, it's still coming through. But you're
out there driving towards it anyway, and each improvement raises the
price of the car...would you accept double the price of the car each
time? For fractional improvements?

/dps