Post-test inspection of Morton Thiokol's space shuttle booster fired April 22 has shown that at least one of the joints performed as expected.

But the jury remains out on the critical center field joint, which contained a built-in flaw. Results are also still being awaited on the case-to-nozzle joint, which also had deliberate flaws.Members of a combined Morton Thiokol/NASA inspection team said the aft field joint looked good, but they had yet to complete their examination of the center field joint. NASA officials say that if the joint sealed despite the flaw, it will demonstrate the joint's fail-safe measures.

The booster redesign must pass two more qualifying tests before the shuttle Discovery can be cleared to fly in early August. The remaining two tests are scheduled for June and July.