Small areas of loose insulation have been found in at least four of the eight solid-fuel booster segments needed for the first post-Challenger shuttle mission, officials say.

But NASA engineers said Tuesday it appears the insulation "unbonds" can be repaired with minimal impact on the launch processing schedule, although an extensive series of tests will be required to confirm whether the fix will prevent further problems."I feel, at this point, it is a good repair and the tests we are going to accomplish will, in fact, verify that before we launch," said Bob Marshall, manager of the shuttle projects office at the Marshall Space Flight Center in Huntsville, Ala.

In the meantime, the National Aeronautics and Space Administration is proceeding with repairs and booster assembly on the assumption that the test program will prove the current repair technique is sufficient. The shuttle Discovery is scheduled for blastoff in August.