WASHINGTON — Veteran space lobbyist Mark Bitterman left United Launch Alliance Jan. 14 after more than three years as vice president of government affairs for the Denver-based launch company.

Bitterman informed colleagues of his departure in an email, a copy of which was obtained by SpaceNews.

Bitterman established himself in Washington lobbying circles at Orbital Sciences Corp., where he served for 19 years as the company’s government affairs lead. He departed in September 2011 to take a position with rocket maker SpaceX, where he worked briefly before joining ULA.

Bitterman “has decided to leave the United Launch Alliance to pursue independent business/consulting opportunities,” ULA spokeswoman Jessica Rye wrote in a Jan. 15 email. “In the interim, Chris Andrews, director of strategic planning and business development, will lead the government affairs and communications organization.”

Bitterman did not immediately reply to an email requesting comment.

ULA, a 50-50 joint venture of Boeing Co. and Lockheed Martin, launches the vast majority of U.S. government space missions.