Editor's note: Atlantis' journey to the International Space Station will be NASA's 135th and final mission in the space shuttle program, which began 30 years ago. Tune in to CNN's live coverage of the launch Friday, starting at 10 a.m. ET on CNN, CNN.com/Live and the CNN mobile apps. Then check out "CNN Presents: Beyond Atlantis" Friday at 10 p.m. ET.
Despite a good chance of thunderstorms, the four-member crew of Atlantis climbed aboard the fueled-up ship and prepared to blast off Friday morning in the final mission of America's 30-year space shuttle program.
The very last launch for a space shuttle is set for 11:26 a.m. ET.