Cracked Door Hinges Jeopardize Year's First Shuttle Flight
Feb. 19, 1991
CAPE CANAVERAL, Fla. (AP) _ NASA's first shuttle flight of the year, a March military mission, could be delayed up to a month because of cracked door hinges that appear limited to Discovery, officials said Tuesday.
A quick check of the other two shuttles uncovered chipped paint on the hinges but no cracks, said launch director Bob Sieck. Those shuttles will be examined more thoroughly and their inspection records will be reviewed, he said.
Cracks were discovered in Discovery at the launch pad on two of the four aluminum hinges on two flapper doors. The doors on the belly of the shuttle are supposed to close once the big external fuel tank drops off shortly after liftoff.
The cracks are 2 inches long and about one-eighth of an inch wide.
Engineers feared Discovery's two other door hinges also were cracked, but further inspection showed they were fine, said Charles Stevenson, chief of the orbiter mechanical systems branch. There was no evidence of chips in the anti- corrosive paint on the hinges.
Engineers were studying the problem to determine whether to return Discovery to the hangar for repairs - a move that would mean a delay of several weeks to a month - or go ahead with liftoff around March 9.
The shuttle may have been flying with the cracks for some time without any problem, said John Fairey, a NASA official in charge of Discovery's pre-launch operations.
Both doors must be kept closed during the shuttle's return to Earth to keep out the intense heat of re-entry.
During Discovery's eight-day flight, the astronauts will release a ''Star Wars'' spacecraft that will study the shuttle's exhaust plumes. The Pentagon will use the information to develop sensors for detecting enemy missiles.
The mission already is 1 1/2 weeks late because of work to replace three bad steering thrusters.
NASA had been hoping for a smooth year after 1990. Hydrogen leaks crippled two of the three shuttles last summer, pushing three of the nine flights planned for 1990 into this year. Seven missions are scheduled this year.
''I'm sure there are a lot of people that are getting that 'here we go again' feeling,'' said NASA spokesman Karl Kristofferson. ''The team has been through this so many times. Hopefully, it will be a problem that can be solved fairly quickly.''