1.   Stormy weather, however, could keep the shuttle grounded until next week.

2.   They include continuing to fly without changes, flying while changes in the nozzle are made or grounding the shuttle.

3.   The shuttle had been grounded because of trouble with bolts, a valve, wind and a pin.

4.   The shuttle would be grounded until May.

5.   The shuttle had been grounded since last Thursday because of trouble with bolts, a valve, wind and a pin.