The new $145-million Mobile Launch Platform at Kennedy Space Center will serve the next generation of manned space flight under the Constellation space exploration program. It will be used for assembly, testing and servicing areas at existing space center facilities; to transport the Ares I rocket to launch pad; and to provide ground support for launches.

Photo Courtesy Hensel Phelps Construction Co.

The tower of the mobile launcher is 405 ft tall and weighs 6.8 million lbs.

Constructing a mobile launch platform with a main support structure, including a base, tower and facility ground systems, presented challenges for Hensel Phelps Construction Co., which began the job in May 2008. The project included the offsite fabrication, transport and erection of steel girders. Two cranes were used for a tandem pick to lift the girders.

During the lifting, one girder experienced bending beyond its allowable yield limit, which resulted in permanent member deformation.

An analysis determined that the lifting lugs had been improperly placed to support the self weight of the member. A fracture analysis engineering firm determined the affected zone of the member. The team was able to determine the amount of damaged material to be removed from the girder for replacement.

Hensel Phelps crews worked multiple shifts and extended hours to recover the lost time, and the base milestone was achieved on schedule.

Hensel Phelps assembled the tower on the ground in 10 different tiers ranging from 20 ft to 45 ft tall and 40 ft to 80 ft wide, with each weighing from 136,000 to 299,000 pounds lbs. The block and rigging on the 480-ft boom of the 1,000-ton capacity crawler crane weighed 58,000 lbs.

Hensel Phelps awarded more than 47% of the subcontracted value to small businesses. It also mentored Palm Bay Aluminum, a small residential firm, enabling it to develop commercial contracting skills. Construction wrapped up in July.

Key Players

Owner: NASA
Contractor: Hensel Phelps Construction Co.
Architect: Reynolds, Smith and Hills
Engineer: Reynolds, Smith and Hills