CAPE CANAVERAL, Fla. — Rain threatened to delay space shuttle Discovery's homecoming Monday and keep its seven astronauts in orbit an extra day.
Discovery was scheduled to land at 8:48 a.m., two weeks to the day since it rocketed away to the International Space Station. Its re-entry path was going to cut diagonally across North America from northwest to southeast, providing a phenomenal light show, weather permitting.
But well before dawn, it was drizzling at Kennedy Space Center. Mission Control informed shuttle commander Alan Poindexter that the rain appeared to be moving offshore. "Hopefully, things will clear out," Mission Control radioed.
"We know you guys will be working it hard," Poindexter replied. "Looking forward to landing in Florida today if the weather works out."
Mission Control needed to decide at least an hour in advance whether to shoot for the first of the morning's two landing attempts. The second touchdown opportunity was at 10:23 a.m.
The volcanic eruption in Iceland, at least, was not interfering with NASA's effort to bring Discovery home. The re-entry path does not go anywhere near the European airspace threatened by volcanic ash.
For the first landing attempt, Discovery would be streaking down over British Columbia and Alberta, Montana and the Dakotas, Sioux City, Iowa, Missouri, the border of Arkansas and Tennessee, northeastern Mississippi and Alabama, then southwestern Georgia and on into Florida, almost directly over Jacksonville.
The second try would have the shuttle descending slightly more to the south, over Washington state and the nation's heartland.
The last time a shuttle crisscrossed the U.S. was in 2007. After this mission, no more are planned as the shuttle program draws to a close. NASA has tried to keep continental flyover re-entries to a minimum for public safety reasons, ever since Columbia shattered over Texas in 2003.
Mission Control said if Discovery can't return to Earth on Monday, the Florida forecast looks more promising for Tuesday and there's always the backup touchdown site in Southern California. The shuttle has enough supplies to remain in orbit until Wednesday.
The astronauts are wrapping up a successful two-week trip to the space station. They left behind tons of science experiments and equipment so the orbiting outpost can operate for years to come. Their biggest contribution was a new tank full of ammonia coolant; it took three spacewalks to hook it up.
A pressure valve in the space station's cooling system got stuck after the ammonia tank was plugged in. Astronauts will have to deal with the problem on a future spacewalk. For now, though, the lab complex is being cooled properly.
This is Discovery's next-to-last flight. NASA has only three shuttle flights left NASA has only three shuttle flights left before retiring the fleet. Atlantis is next up in less than four weeks. The final shuttle mission — by Discovery — is scheduled for September.