Around 4:50 p.m. est, the space shuttle Discover cleared the tower of the Kennedy Space Center in Cape Canaveral, Florida, for its final launch. After a brief repair, the liftoff occurred with only two seconds left to spare in the day’s launch window. By now, the shuttle and its six astronaut passengers are in orbit. It is the shuttle’s 39th mission. There will be only two more shuttle launches before NASA discontinues the program: The Endeavour in April and the Atlantis in late June.