HOUSTON, Dec. 2 (UPI) -- NASA might delay the next U.S. space shuttle launch because of recently discovered cracks in a foam "ramp" on the shuttle's external fuel tank.
The National Aeronautics and Space Administration shuttle program manager, N. Wayne Hale, said in an internal memo the finding might present an "unacceptable safety threat" to the orbiter, the Washington Post reported Friday.
The ramp cracks were discovered last month during an inspection. The vertical cracks in the external tank's "protuberance air load," or PAL, ramp extend deep into the foam insulation and appear to have been caused by contraction and expansion as the tank was being filled with super-cold liquid hydrogen and oxygen, the memo said.
Because all shuttle fuel tanks undergo such "cryoloading," cracking "must be presumed possible in any PAL ramp on any flight vehicle," Hale wrote.
Hale said the judgments were "preliminary" but it "appears mandatory" that the shuttle team must eliminate the ramp for upcoming shuttle flights, including the May launch.