The seven-strong crew of the shuttle Discovery is spending another day in orbit, after Monday morning’s scheduled landing was postponed for 24 hours. Bad weather conditions in Florida caused the delay. NASA feared low-lying cloud could have obscured the runway.They will try again on Tuesday with Cape Canaveral once again chosen for touchdown, although back-up sites are also available in California and New Mexico. The orbiter’s return to earth is set to be a nail-biting moment. It is the first shuttle mission since the Columbia craft broke up as it attempted to land in February 2003. In the two and a half years since, NASA has worked to upgrade safety procedures. Despite this, like the doomed craft, Discovery had a problem at lift-off. Both shuttles shed foam, although damage to Discovery is said to be minor and, after an unprecedented repair job in space, NASA is confident all will be well. To get to grips with the flying debris problem, the agency has grounded its shuttle fleet. However, speculation is increasing about a possible flight next month. For the moment, the main concern is ending this mission safely.