NASA has signed a $16.8 million contract modification to space shuttle main engine manufacturer Pratt & Whitney Rocketdyne Inc. of Canoga Park, Calif., to incorporate an employee retention plan implemented by the company. Incentives are being provided to eligible personnel to ensure mission success and construction of the remaining engines to support space shuttle requirements through September 2010.

Retention of the knowledgeable and skilled space shuttle main engine workforce is necessary to produce the remaining shuttle hardware. This contract modification supports the agency's priorities of safely flying and retiring the space shuttles.

The contract will end Sept. 30, 2010. This modification brings the total value of the contract, awarded in January 2002, to $2.181 billion.

The three main engines are 14 feet long and seven and a half feet in diameter at the nozzle exit. They are liquid propellant rocket engines that have a combined thrust of more than 1.2 million pounds. Along with the solid rocket boosters, they provide the thrust to launch the shuttle.

For more information about NASA's Space Shuttle Program, visit: http://www.nasa.gov/shuttle