Shuttles grounded?

"Pat Flannery" wrote in message
dakotatelephone...


Brian Gaff wrote:
As far as I'm aware, late release should not be aproblem as the breaking
forces of the atmosphere could not impart much differential velocity to the
debris. There is always debris on tank release and just before.

In this case, the major foam shedding was fairly early in the flight when a
combination of acceleration and air density can make the shed foam pick up
enough velocity to do damage on impacting the Shuttle.
Shedding occurred at 1 minute 47 seconds, 1 minutes 55 seconds, and 6 minutes
17 seconds. Although the last piece was pretty large... around six inches
square... by that time air density was low enough that it didn't develop any
dangerous degree of acceleration in relation to the ascending orbiter/ET stack


Could the foam problem have anything to do with how many times
they attempted to launch? This one did take three tries was it?


Jonathan



Assuming the shed foam from the intertank structure earlier on was 1/2 inch
thick, as NASA states, then a piece 4 inches wide by 3 feet long equals 36 x 4
= 144 x .5 = 72 cubic inches (this is a minimal estimate, on the ET photos
after jettison some of the shed pieces look as much as 5 feet long, and the
foam wraps around the ribs on the intertank, so flattened out it could be
wider than 4 inches. Assuming 5 feet long and 6 inches wide gives 180 cubic
inches as a max estimate).
This compares to the far larger piece that hit Columbia that was estimated to
be around 1,200 cubic inches in volume.
So although in all likelihood too small to damage the leading edge RCC panels
much, this is a lot larger than the pieces normally seen due to "popcorning".

Pat