Watch live: Endeavour pre-launch news conference

NASA's day-before-launch news conference is expected to start at 11:45 a.m. at Kennedy Space Center.

Watch it live by clicking on the the big picture above or the NASA TV still image on the right side of the page to launch a viewer.

Participating are:
- Mike Moses, chair, Mission Management Team.
- Pete Nickolenko, shuttle launch director.
- Kathy Winters, shuttle weather officer.
- A Japan Aerospace Exploration Agency representative.

Space shuttle Endeavour and seven astronauts hope to blast off at 7:39 p.m. Saturday on a 16-day International Space Station construction mission.

Hydrogen gas leaks during two launch attempts in June delayed the mission about a month, but NASA believes it has a handle on the problem.

But Saturday's weather forecast offers only a 40 percent chance of acceptable launch conditions because of widespread thunderstorms.