Mission managers have given space shuttle Discovery a go for today's planned launch.
The 39th flight of the orbiter is set to lift off from Kennedy Space Center at 4:50 p.m. This is the final flight of Discovery, the oldest of the three remaining ships in the space shuttle fleet.
The six astronauts will go to the launch pad at 1:30 p.m.
The mission was originally slated to launch in November, but cracks in the external fuel tank forced repairs and the four-month delay.
There's an 80 percent chance of good weather and no significant technical hurdles in the way.
"Discovery looks like she'll fly this time," said shuttle launch director Mike Leinbach.
"Just landed after some T38 (trainer jet) flying around the Cape. A little g (gravity) loading before launch. Beautiful!" astronaut Nicole Passonno Stott, 48, who grew up in Clearwater and attended Clearwater High School, said in a Twitter update Tuesday morning.
Stott, one of the six astronauts slated to fly today, spent three months aboard the International Space Station in 2009.
Discovery will take thousands of pounds of supplies and Robonaut 2, a humanoid robot, to the International Space Station.
Since its first flight in 1984, Discovery has logged nearly 143 million miles in space, with another 4.5 million miles expected during its upcoming journey, making it the most traveled reusable spacecraft.
It carried up the Hubble Space Telescope in 1990, returned John Glenn to orbit in 1998, and got shuttles flying again after the deadly Challenger and Columbia tragedies.
"The last flight of all three vehicles is going to be emotional for all of us," Leinbach said. "I think the emotion will really hit us on the runway when the mission is complete."
"We feel like we're doing something special for the country and really the world … and it's coming to an end, and it's tough."
Information from the Associated Press and McClatchy Newspapers was used in this report.