WASHINGTON — Robert Strain is resigning as director of NASA’s Goddard Space Flight Center in Greenbelt, Md., to become chief operating officer of Ball Aerospace & Technologies Corp.

“It is with mixed emotions that I announce my intention to leave NASA Goddard and return to industry,” Strain wrote in a Jan. 30 memo emailed to Goddard employees. “My last day as Director will be March 4.” Strain has held the top post at Goddard for more than three years.

NASA has not yet chosen a replacement for Strain, NASA spokesman Mark Hess said.

At Boulder, Colo.-based Ball, Strain will be responsible for day-to-day operations of the company’s Civil and Operational Space, Tactical Solutions, National Defense, and Systems Engineering Solutions units. He will report directly to David Taylor, president and chief executive of Ball Aerospace.

Before taking the reins of Goddard in 2008, Strain was the head of the Space Department at the Johns Hopkins University Applied Physics Lab in Laurel, Md. Prior to joining Hopkins in 2004, Strain spent 10 years at Dulles, Va.-based satellite and rocket maker Orbital Sciences Corp., where he was executive vice president of space systems.

Ball is working on several big projects being managed by Goddard. Among these is the Joint Polar Satellite System (JPSS), the next generation of U.S. civil polar-orbiting weather satellites.

Ball is the prime contractor for the JPSS-1 spacecraft, which NASA is procuring for the National Oceanic and Atmospheric Administration. Ball has a $248 million fixed-price contract to build JPSS-1, and a separate $82.4 million contract to build a clone of the Ozone Mapping and Profile Suite instrument.

The 2012 budget for JPSS is $924 million.

Dan Leone is a SpaceNews staff writer, covering NASA, NOAA and a growing number of entrepreneurial space companies. He earned a bachelor’s degree in public communications from the American University in Washington.