It's taken four months to get this far, but the space shuttle Discovery is finally set for launch this Thursday afternoon.
The shuttle's 39th and last flight will take a cargo carrier to the International Space station. NASA says the weather forecast gives an 80 percent chance that the launch will - finally - go ahead as planned.
All six astronauts for Discovery's final mission, STS-133, are now at the Kennedy Space Center for prelaunch preparations, and commander Steve Lindsey and pilot Eric Boe have been practicing landing approaches in a Gulfstream II jet modified to simulate a shuttle's cockpit, motion and handling qualities.
Around lunchtime today, engineers will start loading Discovery's fuel tanks with liquid hydrogen and oxygen.
The delays were caused by cracks to the 'stringers' supporting Discovery's external fuel tanks - all sorted now, says NASA.
"I’ve been through a lot of shuttle issues for many years, and this is probably one of the most difficult technical issues, I think, we’ve ever faced because the answers were not obvious," says Lindsey.
"It wasn’t obvious what was wrong, why it was wrong, or how to fix it, and then you had the additional, if you will, pressure of the shuttle program winding up and we keep slipping and slipping and slipping."
During its 27-year career, Discovery has clocked up 322 days in space, orbiting the Earth 5,247 times - indeed, it's flown more than any other shuttle. After its return from the 11-day mission it will be retired and sent to a museum, probably the Smithsonian.