Don't expect another shuttle launch any time soon.

The next shuttle mission had been scheduled for September, but now is expected to occur no earlier than March.

NASA grounded its fleet after a large, potentially deadly chunk of foam insulation broke off Discovery's modified external fuel tank during liftoff last month.

Unlike in Columbia's tragic case, the piece did not hit the space ship this time. Columbia was destroyed on re-entry in 2003 after its left wing had been cracked during takeoff by a piece of the foam.

One of the main missions of Discovery's flight was to test new methods of inspecting the orbiter for damage and repairing any problems that are found.

Critics say NASA has been putting astronauts at risk by rushing to launch to meet deadlines even as design problems persist. A minority report from an oversight committee that was released Wednesday said the culture of NASA was still dangerous.