The 14-day mission will see the Discovery shuttle deliver its heaviest payload to the International Space Station, the Japanese Pressurized Module (JPM) which is the second unit of the massive Kibo laboratory complex.
The first unit, an experimental logistics module, was delivered to the ISS in March.
Three spacewalks are also planned during the shuttle crew's nine-day stay on the ISS installing the Kibo's JPM along with a remote manipulator system (RMS) comprising two robotic arms.
Lift off is scheduled for 17:02 local time (21:02 GMT) and will be the third shuttle launch this year and the 35th for Discovery. The shuttle is expected to dock with the ISS two days after launch.
The STS-124 shuttle crew will be commanded by Mark Kelly, 44, with Ken Ham serving as pilot. Mission specialists will include Karen Nyberg, Ronald Garan, Michael Fossum and Japanese Aerospace Exploration Agency (JAXA) astronaut Akihiko Hoshide.
The seventh crew member Greg Chamitoff will replace Garrett Reisman, who has been on the ISS for three months.
