Pedro L. Rustan is retiring from the U.S. National Reconnaissance Office (NRO) at the end of October, according to a spokesman for the spy satellite agency.

Rustan was recently director of the NRO’s Mission Support Directorate, after serving as director of ground enterprise and advanced systems and technology directorates.

He started off as a research scientist and test engineer for the U.S. Air Force in the 1970s, and became a program manager on radiation effects for the Defense Nuclear Agency in 1986. Rustan joined the Ballistic Missile Defense Organization in 1989 and was the Clementine spacecraft program’s mission director for five years. He was responsible for managing the mission from its beginning to full operations. Clementine mapped the surface of the Moon using five cameras, discovering ice deposits.

Rustan then moved on to the NRO in 1994 as a director of small satellite development. After spending six years consulting and working with private space companies, Rustan returned to the NRO in 2003.

NRO spokesman Richard Oborn said that although Rustan’s official retirement date is the end of October, his last day in the office was in late July.

Oborn said Rustan intends to stay involved in the space business but has not made any decisions about his next endeavor.

“He’s a guy who’s always looking for a challenge, always looking for something to do,” Oborn said.