Florida ? NASA started a countdown Tuesday toward the first space shuttle flight of the year. Engineers reported no major technical problems and the weather forecast looked favorable for a Friday launch.

The countdown clock began ticking on schedule Tuesday at 8 p.m. CDT.

There was a 70 percent chance that the weather would be suitable at 6:38 p.m. CDT Friday, NASA’s first opportunity to launch space shuttle Atlantis. The shuttle will carry seven astronauts on an 11-day mission to deliver a third pair of solar wings, which help power the international space station. They also will take three spacewalks to continue construction of the orbiting outpost.

Thunderstorms are predicted for Friday afternoon – normal for a Florida summer day – but they should move inland by launch time, said Kathy Winters, shuttle weather officer.