11.   If the shuttle cannot land in Florida, a backup landing site at Edwards Air Force Base would be available Thursday.

12.   If the shuttle cannot land, a backup landing site at Edwards Air Force Base in California would be available on Thursday.

13.   Shuttle lands as crew faces inquiry into mistakes.

14.   The shuttle probably could land safely with just one of the units, but NASA prefers to have two working backups.

15.   They held out hope the shuttle could land during the second and last attempt for Tuesday, but the weather did not improve.

16.   Where the shuttle lands, and whether it lands in one piece, has long been a matter of debate.