THE FINAL FLIGHT

If all goes as planned, Atlantis will blast off at 10:26 a.m. CDT Friday from Kennedy Space Center in Cape Canaveral, Fla., for a 12-day mission to the International Space Station and the final flight of the space shuttle program.

The shuttle fleet had just five spaceships, plus a prototype, Enterprise, that never made it to orbit. In total, vessels have flown 537 million miles (NASA's exact number: 537,114,016). Discovery, Endeavour and Atlantis are the three surviving orbiters. The two oldest shuttles met disaster. Challenger blew up in 1986 as it soared into the Florida sky, and Columbia disintegrated over Texas as it returned to Earth in 2003.