scope:

Abstract:

The flight element design agency modified the design of the External Tank Ground Umbilical Carrier Plate, which is used to vent hydrogen. The design changes were considered minor enough that modeling and simulation were deemed sufficient to certify the part for use. During STS-114 launch operations, a camera recorded a cryogenic liquid leaking from the shroud used for purging the umbilical. Because oxygen liquefies before nitrogen, the evidence of liquid caused a concern that oxygen was liquefying from air and posing a risk to launch operation safety.