NEWS: Cryopumping still lead suspect in foam frazzle

Kent Betts wrote:

First the engineers were speculating that air and moisture were getting
under the foam and getting frozen. Now the idea is that there is stuff
under the foam but it is not frozen water from outside, it is cryogenic gas
from inside the tank.

You misunderstand the report. The cryogenic liquid-gas was liquefied
air that seeped by or through the foam. There was no cryo leak.

Mike Walsh

I don't buy it, because what are the odds that the cryo leak and so forth
would occur under the biggest chunk of foam on the tank? I think the foam
chunk came off because it was hanging too far out in the airstream and was
not of adequate mechanical or aerodynamic design to stay attached at Mach
one.

The tank attach point insulation is going to get a rework. No mention of it
in the press for months. Heh heh....a little amusing that the most direct
remedy, fixing the thing that actually caused the accident, is the easiest
task on their return to flight to-do list.

"Michael Walsh"

You misunderstand the report. The cryogenic liquid-gas was liquefied
air that seeped by or through the foam. There was no cryo leak.

"We've found out that the bolts and the nuts being applied to actually
construct the different areas of the tank ... before you put the insulation
on, that any kind of gap in there might be an opportunity for liquid
nitrogen or liquid air to form,"

The article refers to a "different type of cryopumping" but is not explicit
as to what this means. I agree that it does not say that there is a
cryogenic leak. This was an erroneous supposition on my part upon reading
about gaps in the fasteners. It says that gaps around the nuts and bolts
provide an opportunity for air and nitrogen to freeze. So at launch time,
this frozen stuff heats and expands and does bad stuff to the foam.