As the penultimate shuttle launch counts down, traffic jams may cause gridlock on the Space Coast.
Traffic woes may mire shuttle launch plans as an estimated 750,000 spectators will converge around the Kenendy Space Center area Friday.
U.S. President Barack Obama and U.S. Congresswoman Gabrielle Giffords among launch guests.
Stricken congresswoman "feisty, fired up," says NASA chief.
UPDATE: Today's shuttle launch has been scrubbed because of a concern associated with Auxiliary Power Unit 1 heaters. NASA will hold a press conference to address the issue.
With up to 750,000 spectators expected to converge around the Kennedy Space Center area Friday, NASA's launch team has an added concern if weather or technical problems delay today's launch of shuttle Endeavour -- traffic.
"Driving home is going to be a challenge and that's going to factor into our decision this time more so than ever in the past," launch director Mike Leinbach told reporters.
Liftoff is slated for 3:47 p.m. EDT. Meteorologists on Thursday predicted a 30 percent chance the weather could be a problem for launch. Typically, NASA would try again 24 hours later. This time, however, 48 hours might be needed to allow workers enough time to get home, get rested and return to the space center to try again.