Space Forum / Shuttle / March 2007

If you've never had your car beat to pieces or the roof on your house
shredded by a hail storm you are a lucky one. Golf ball sized hailstones
could kill a person hit in the head with them. Apparently you have never
lived in an area that has large hail.

diy-newby beweerde :

You talk about 2 completely different stresses:
A hailstone is stress on a very tiny spot.
Flying super- and hypersonic have a larger surface where the stress is
on.

Example:making a (real!!) deep hole is easier with a drill, than with a
sledge-hammer

André

The tank itself is made of an aluminum lithium alloy, but it's coated with a
spray on foam insulation.  This insulation serves many purposes.  Firstly,
it is there to keep the liquid oxygen and liquid hydrogen cold.  Secondly,
it's there to prevent ice from forming on the outside of the tank.  Thirdly,
it's there to prevent heat, from the aerodynamic heating during flight, from
heating up the tank.

And finally, the insulation is on the outside of the tank for a several
reasons.  Firstly, putting it on the outside allows the aluminum-lithium
tank to be made lighter, because the strength of this alloy is higher at
LOX/LH2 temperatures than it is at your typical Florida temperatures.
Secondly, it's on the outside to eliminate any possibility of the insulation
coming loose and getting sucked into the SSME's turbopumps.  Thirdly, if
it's on the inside, it can't protect the tank from aerodynamic heating.

And, of course, NASA is very cautious about how they deal with the ET
insulation since it was the root cause of the Columbia disaster.

Jeff

you're obviously very uneducated about how spaceflight works.  Do some
research.. sure you could build a rocket damage-resistent to
anything.. but it'd be so heavy it'd never get off the ground.