Hello, Leonard.

Please also see my response to Matt.

 JH> Unfortunately, I didn't see anything about the rationale for the 500+
 JH> mph impact.  In any event, it is clear that the shuttle was moving out
 JH> smartly, and the lightweight insulation must have slowed down a lot
 JH> due to air friction before it struck the wing of the orbiter.

 LE> The insulation wasn't falling that fast.

Hmmm - How "fast" do you think that there chunk of insulation may have
been "falling" with respect to the rest of the launch vehicle? How can
we get to a 500+MPH differential velocity?

Have you ever held your arm and hand out the window of a vehicle
travelling maybe 70MPH on Interstate?  Strong forces, right?
At subsonic velocities, wind forces increase as the square of the
velocity, so at just 490MPH vs. 70MPH, wind forces would be 49 times
greater, right?

 LE> But the orbiter was moving up
 LE> at (as you said) "a fair clip". So it was actually more a
case of the
 LE> wing hitting the insulation rather than the other way around.

Well, they hit one-another, that is for sure. [;-D.  Orbiter Wing was
accelerating its way up into orbit.  Insulation piece was decellerating
its way back toward earth after falling off of its appointed station.
Hey, maybe we need some of them litigating lawywers to get into this to
finally decide who hit whom?  (ROFL)

You want to run some numbers on a "piece of insulation" falling away
from somewhere on the External Tank and impacting an Orbiter wing panel
maybe 120' tops downstream?   Unless you figure in some drastic
decelleration for that lightweight insulation piece, I think you won't
ever get to a relative speed difference of 500+ MPH as NASA is using for
their tests.

Or, lets think of a simple-minded experiment -  get out on Interstate,
going 70MPH, and take along a piece of say 8"x8"x8" styrofoam
insulation.  Hold it out the window at that constant speed, then turn it
loose - I think you already know that you can expect that you will see
it decelerate rapidly wrt your constant-velocity vehicle, due to the
force of wind friction on it.  The air friction effect would be even
more dramatic at higher vehicle velocity

Good luck
- - -   JimH.

... Inquiring minds want to know. - Bubba
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