WASHINGTON — The U.S. Senate Commerce Committee’s top Democratic staffer on science and space issues is stepping down Nov. 7 to take a government affairs position with Lockheed Martin.

Ann Zulkosky joined Senate Commerce in 2007 as a National Oceanic and Atmospheric Administration legislative fellow, but spent most of the last seven years working on civil space matters under Sen. Bill Nelson (D-Fla.), who chairs the science and space subcommittee.

Zulkosky, reached by email Oct. 20, said she will start at Lockheed Martin’s Washington office Nov. 11. She will be Lockheed’s director of NASA programs, replacing Mike Hawes, the former senior NASA official who replaced Cleon Lacefield as Lockheed’s Orion program manager over the summer.

A veteran aerospace lobbyist called Zulkosky’s departure a “huge loss” for the Senate, which now has seen two civil space policy experts leave in just more than a year. Her longtime Republican counterpart, Jeff Bingham, retired in August 2013. Bingham and Zulkosky worked closely on several key civil space bills, including the 2010 NASA Authorization Act that called for funding development of commercially designed and operated crew taxis to service the international space station while also building the NASA-owned-and-operated Space Launch System rocket and Orion capsule for crewed missions to deep space.

It was not immediately clear who will replace Zulkosky, who declined to discuss personnel changes. Senate Commerce Committee spokeswoman Rachel Petri, reached by phone Oct. 20, had no immediate comment about Zulkosky’s successor. One industry source said Richard-Duane Chambers, a junior Commerce Committee staffer who came to the Hill in April 2013, is in the running.

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.