Preliminary results show that two of three joints on the redesigned space shuttle booster rocket did not leak during an April 22 qualifying test, a NASA official said today. Dave Mobley, NASA deputy project manager for the redesign effort, said that engineers have inspected the aft and center field joints and found both to be working as designed. Results of tests on the forward joint are expected Friday. Mobley said today that engineers found that the center field joint, which had an intentional flaw built into it for an April 22 test-firing at the Morton Thiokol plant 25 miles west of here, did its job. He said the center field joint flaw allowed superhot gases to reach insulation and the joint's O-ring, but the ring held. ``There was no damage to the O-ring at all,'' he said. ``There was no evidence the gas got past'' the ring. Failure of an O-ring seal is blamed for triggering the Jan. 28, 1986, explosion that destroyed the space shuttle Challenger and killed its seven-member crew. The booster tests are designed to evaluate the redesigned booster, which is made up of several sections that are joined together, and qualify the joints for use in an actual launch. Mobley also said engineers found no damage to the rocket's nozzle section. In a December test-firing, a redesigned boot ring on the section came apart. The April test used a boot ring that had proven reliable in the past. Mobley said engineering evaluations would be conducted late today on the redesigned booster's forward field joint, with results expected Friday. He noted that while thorough, results from the evaluations were tentative. A final report, based on more extensive study, isn't expected to be ready for several weeks, he said. Two more full-scale tests of the booster are planned for June and July, and the shuttle launch is tentatively set for late August or early September.
