Alliant Techsystems Inc., the sole maker of reusable solid-rocket motors for U.S. space shuttles, has won a contract valued at more than $50 million to build solar arrays for NASA's new Orion spacecraft.

The solar arrays are expendable for each mission, which should mean continuous production at least through 2020, Alliant said Friday in a statement. The award came from Lockheed Martin Corp., the lead contractor for the National Aeronautics and Space Administration's Orion program.

Alliant, based in Edina, Minn., also the U.S. Army's largest supplier of rounds for M-16 rifles, is expanding sales of spacecraft components to keep revenue growing as ammunition sales slow with the winding down of the Iraq war. Chief Executive Officer Daniel Murphy said this week the company would buy MacDonald, Dettwiler and Associates Ltd.'s space unit for $1.32 billion to enable the company to build complete satellites.

Work on the solar arrays, which will power Orion as it carries crews to the International Space Station and eventually to the moon, will be done at Alliant's plant in Goleta, Calif. Orion will replace the current fleet of U.S. space shuttles.

Alliant's employees include nearly 5,000 workers at seven facilities in Utah. The Utah employees work on solid-fuel rocket launch systems, satellites and advanced composites.