Space shuttle program officials have affirmed a new launch schedule to accomplish six flights over the next 12 months that will expand the space station to include the international science laboratory modules.

The revised manifest, which involves switching some mission assignments between shuttles Atlantis and Discovery, was developed in the wake of the three-month delay in launching the next flight.

Atlantis' planned March mission was grounded after an extraordinary hail storm in late February caused extensive damage to the foam insulation on the external fuel tank while the shuttle stood on the launch pad. The shuttle was forced back to the Vehicle Assembly Building for repairs.

NASA has rescheduled the STS-117 launch for June 8 at approximately 7:34 p.m. EDT (2334 GMT). The crew will deliver and attach the S3/S4 solar array structure to the starboard-side of the station's truss backbone. The electricity-generating wings are crucial for powering the station's forthcoming expansion.

Endeavour takes its first flight since 2002 on the STS-118 mission carrying the final Spacehab logistics module and the S5 truss spacer structure. The crew includes Barbara Morgan, the former Idaho teacher and NASA's first astronaut trained as an educator mission specialist. Liftoff is targeted for August 9 around 6:15 p.m. EDT (2215 GMT).

The station's connecting module that will serve as the passage way between the U.S. and international laboratories launches aboard Discovery around 1 p.m. EDT (1700 GMT) on October 20. The Harmony module, formally called Node 2, will be delivered to the station and the Port 6 solar array truss relocated from its initial position atop the complex to the permanent outboard location. The STS-120 mission has been moved from Atlantis to Discovery as part of the manifest shuffling.

Once Discovery departs, the station's Expedition 16 crew must peform three spacewalks and robot arm operations to place Harmony on the front-end of the U.S. Destiny laboratory where it becomes the new docking port for visiting shuttles and the hub for attaching additional modules.

The European Space Agency's Columbus science laboratory will be ferried to the station by Atlantis' STS-122 flight for installation on Harmony. The mission was switched from Discovery. Launch is slated for December 6 around 4:30 p.m. EST (2130 GMT).

Endeavour flies the 25th shuttle trip to the station on mission STS-123. Scheduled for launch around 12 noon EST (1700 GMT) February 14, the shuttle will haul the Japanese experiment logistics module, the first of three station elements representing Japan's primary contribution to the outpost.

Japan's main science lab goes up on STS-124. Discovery is slated to launch the Kibo facility on the morning of April 24.

Officials say dates for the remaining flights through the shuttle retirement in 2010 have not been set. Eight and possibly as many as 10 flights could occur in the final two years of the shuttle program, including the Hubble Space Telescope servicing mission expected late next summer.