ET Thermal Conductivity

Question:

Is it possible that the change in thermal conductivity between the
alloy used to build the Lightweight ET and the Super Lightweight ET is
the cause of the increased cryopumping that has led to foam loss on the
recent tanks? My understanding is that the new aluminum-lithium alloy
has a much lower thermal conducticity than the old material. I was
thinking that this would result in more thermal energy from ascent
heating being trapped at the foam level, vs before when some of that
energy was transmitted into the tank via the aluminum alloy skin.
Likewise, the decreased TC causes the liquid fuel in the tank to not be
able to keep the trapped liquid gases within the foam as cool as before
during ascent, thus resulting in increased cryopumping and resultant
foam liberation.

NASA hasn't really been able to understand the mechanism for foam
liberation despite three years of intensive work on the matter, so I
figured maybe it was time to get some amateur brain power wokring on
the issue.


-Craig

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Relevant Pages

  • Re: ET Thermal Conductivity
    ... Is it possible that the change in thermal conductivity between the ... the cause of the increased cryopumping that has led to foam loss on the ... My understanding is that the new aluminum-lithium alloy ... the decreased TC causes the liquid fuel in the tank to not be ...
    (sci.space.shuttle)
  • Re: ET Thermal Conductivity
    ... Is it possible that the change in thermal conductivity between the ... alloy used to build the Lightweight ET and the Super Lightweight ET is ... My understanding is that the new aluminum-lithium alloy ... Who says the metric system doesn't have unit conversion issues? ...
    (sci.space.shuttle)