The landing of space shuttle Atlantis has been postponed until tomorrow morning at the earliest* because of bad weather at Kennedy Space Center in Florida.

Atlantis had two landing opportunities at Kennedy today, but both were waved off this morning because of elevated crosswinds, a low cloud ceiling and nearby thunderstorms, all three of which fell outside NASA's parameters for a shuttle touchdown.

The first of four landing opportunities tomorrow is at 9:16 A.M. (Eastern Daylight Time) at Kennedy, but continued inclement weather in Florida could shift the site to Edwards Air Force Base in California, which has two landing opportunities Saturday. Landing in California is not as desirable because the shuttle must then be ferried back to Kennedy atop a specially equipped NASA 747 at a reported cost of $1.8 million. Such was the case after space shuttle Endeavour landed at Edwards at the end of November—click here to see an overhead photograph of the orbiter hitching a ride back to the East Coast.

If neither Kennedy nor Edwards pans out tomorrow, Atlantis has six chances to land Sunday, including two opportunities at White Sands Space Harbor in New Mexico.

*UPDATE (5/23/09, 9:05 A.M.): NASA has waved off Saturday's landing opportunities as well. In a statement, Greg Johnson, the mission's capcom, or spacecraft communicator, said, "There's a chance for a landing at Kennedy tomorrow [Sunday], and we're going to keep that option open. Edwards remains good for tomorrow and Monday, if needed."

Photo of Atlantis mission specialist Mike Massimino, aka Astro_Mike, in orbit: NASA