NASA announced that space shuttle Discovery made the long, slow trek out to Launch Pad 39A at the Kennedy Space Center. The 3.4-mile trek is one of the last major milestones leading up to the launch of Discovery on the STS-124 mission. Launch is targeted for May 31.

Space shuttle Discovery’s upcoming STS-124 mission is the second of three flights that will launch components to complete the Japan Aerospace Exploration Agency's Kibo laboratory. The shuttle crew will install Kibo’s large Japanese Pressurized Module, or JPM, and its remote manipulator system, or RMS. The RMS consists of two robotic arms that support operations outside of Kibo. The lab's logistics module, which was installed in a temporary location during STS-123 in March, will be attached to the new lab.

The bus-sized module will be the station’s largest laboratory and will be the second component of Japan's laboratory complex to fly to the station. The first, the Japanese Experiment Logistics Module, was launched in March on shuttle mission STS-123.

The Kibo pressurized module weighs in at 32,000 pounds. It is so large that the shuttle’s Orbiter Boom Sensor System was left at the station during the last mission. There is not room in Discovery's cargo bay for both the boom and the lab.

A third and final shuttle mission to complete the complex will launch an exterior platform for the Kibo laboratory complex that will allow experiments to be exposed to space.

The STS-124 mission carries the heaviest payload to the station and it will include three spacewalks.
The shuttle also will deliver a new crew member, Greg Chamitoff, and bring back another one, Garrett Reisman, after a three-month mission.

Navy Cmdr. Mark E. Kelly will command the STS-124 shuttle mission. Navy Cmdr. Kenneth T. Ham will serve as the pilot. Mission specialists will include NASA astronauts Karen L. Nyberg; Air Force Col. Ronald J. Garan Jr. and Air Force Reserve Col. Michael E. Fossum. Japan Aerospace Exploration Agency (JAXA) astronaut Akihiko Hoshide also will serve as a mission specialist.

The STS-124 crew members are set to arrive at Kennedy on May 6 for the Terminal Countdown Demonstration Test. The three-day event concludes May 9 with a full dress rehearsal of the launch countdown.

The mission will be the third spaceflight for Kelly, the second spaceflight for Fossum and the first spaceflight for Ham, Garan, Nyberg, and Hoshide.

On Earth, STS-124 will mark the first time the JAXA flight control team will activate and control a module from Kibo Mission Control in Tsukuba, Japan. JAXA is scheduled to take over final activation of Kibo on the fifth day of STS-124, the day after the module is installed.

The space shuttle Discovery was brought to the launch pad by the slow-moving crawler-transporter. The shuttle assembly and mobile launcher platform began rolling out of the Vehicle Assembly Building at 11:47 p.m. EDT Friday night and was secured at the pad at 6:06 a.m. on Saturday. The canister carrying the STS-124 payloads arrived at the launch pad April 29.