NASA engineers are studying a tiny crack in a hinge aboard the shuttle Atlantis to determine if the ship can be safely launched without time-consuming repairs like those grounding the shuttle Discovery.

A teleconference was scheduled Wednesday afternoon to resolve the matter before Atlantis' scheduled move from its hangar to the Vehicle Assembly Building Friday for attachment to a pair of boosters and an external fuel tank.Rollout to launch pad 39B is planned for next week with liftoff on tap around April 5, one day later than originally planned. The goal of the flight is the deployment of the 36,000-pound Gamma Ray Observatory, a space telescope built to study extremely high-energy radiation from deep space.

"I'm through trying to figure out how this decision is going to go," one National Aeronautics and Space Administration manager said of the crack issue. "I thought last week we were going to clear Discovery for flight. I'm not sure how this decision is going to turn out."