The six men and one woman who will fly space shuttle Discovery into orbit later today are putting on their spacesuits in preparation for launch. Each astronaut will don their helmets and gloves before technicians pump air into the suit to check for leaks. A team of specialists help the astronauts into the suits and perform the tests.

NASA said that the launch remains scheduled for 5:02 p.m. EDT from NASA's Kennedy Space Center in Florida. The countdown has encountered no technical problems and the afternoon forecast remains optimistic.

Shuttle Weather Officer Kathy Winters announced that the weather is looking promising for launch day. Isolated coastal showers may be in the area during the morning hours, but a sea breeze will develop in the afternoon, clearing the coast and causing any showers to move inland. There is an 80 percent chance of favorable weather at launch time.

The third space shuttle mission of the year will deliver the Kibo pressurized science laboratory to the International Space Station (ISS). Led by Navy Cmdr. Mark Kelly, 44, space shuttle Discovery is set to blast off at 5:02 p.m. EDT on Saturday and arrive at the space station two days later. The shuttle and station crews will install the 37-foot, 32,000-pound Kibo science lab, or JPM, for Japanese Pressurized Module, to the left side of the Harmony connecting node, opposite the European Columbus science lab that was installed in February.

This is Kelly’s third flight into space, having served as pilot on STS‐108 and STS‐121. He will be joined on Discovery by pilot and Navy Cmdr. Ken Ham, 43. Mission specialists include Karen Nyberg, 38, Air Force Col. Ron Garan, 46, Air Force Reserve Col. Mike Fossum, 50, and Japanese Aerospace Exploration Agency (JAXA) astronaut Akihiko Hoshide, 39. Greg Chamitoff, 45, will replace Garrett Reisman, 40, who arrived on the station in March and is completing three months as a station flight engineer. Chamitoff will become a part of the Expedition 17 space station crew and Reisman will become part of Discovery’s crew.

Chamitoff will join expedition commander and Russian Air Force Lt. Col. Sergei Volkov, 35, and Flight Engineer Oleg Kononenko, 43, who were launched to the complex in the Soyuz TMA‐12 spacecraft on April 8 from the Baikonur Cosmodrome in Kazakhstan. Chamitoff will return to Earth in the fall on shuttle mission STS‐126, while Volkov and Kononenko will return in the Soyuz in October.

Kibo is 14 feet longer than Columbus and 9 feet longer than the U.S. Destiny laboratory. It joins the first component of the Japanese segment of the station, the Experiment Logistics Module-Pressurized Section (ELM-PS), which was launched on the last shuttle flight, STS-123, in March. The logistics module will be robotically detached from the top port of Harmony during the mission and reattached to the top part of Kibo to serve as a storage depot. The ELM-PS was launched with eight racks of science gear and control equipment that will be transferred to the JPM for installation. In all, Kibo can house up to 23 racks of equipment and experiments that will involve research in space medicine, biology, Earth observations, materials production, biotechnology and communications.

The new pressurized module also is equipped with its own robotic manipulator system and an airlock. The Japanese robotic device will be comprised of two separate six-jointed arms, the main arm that measures 32.5 feet and can handle up to seven tons of hardware, and a small fine arm, a 6.2 foot extension that will be used for delicate payload operations. The small fine arm will be launched later on a new Japanese re-supply ship for the station called the H-II Transfer Vehicle (HTV). The airlock ultimately will be used once the final components for the Japanese segment of the station are delivered on shuttle mission STS-127.

The inspection of Discovery’s thermal protection heat shield will be conducted differently than on previous flights. Due to the size of the giant Kibo module, the Orbiter Boom Sensor System (OBSS) extension that uses laser devices and cameras to inspect the shuttle’s wings and nose cap could not be mounted on Discovery’s tarboard payload bay sill for launch. Instead, it was temporarily attached to the starboard truss on the station during STS-123.

As a result, on the second day of the flight normally reserved for OBSS inspection, the end effector camera on the shuttle’s robotic arm will be employed to capture initial imagery of Discovery’s heat-resistant tiles. The boom will be retrieved on the fourth day, during the first of three planned spacewalks by Fossum and Garan, and handed back to the shuttle’s robotic arm. It will be used for a detailed inspection of the heat shield, if required, and later, a final inspection of Discovery after the shuttle has undocked from the station. The OBSS will then be brought back to Earth to be reflown on subsequent shuttle missions.

Update: The final few workers still at Launch Pad 39A at NASA's Kennedy Space Center are wrapping up their last chores after closing and locking the hatch that leads into space shuttle Discovery's crew compartment. The seven astronauts who will perform the STS-124 mission are inside the orbiter and working through standard countdown checklists.

Mark Kelly leads the crew and Pilot Ken Ham is in the seat next to him in Discovery's cockpit. Mission Specialists Karen Nyberg and Ron Garan are seated just behind them and will help with checklists and other duties as the shuttle climbs toward orbit. On the middeck,  Mike Fossum, Greg Chamitoff and Japanese astronaut Akihiko Hoshide are strapped in for the launch.