David M. Altwegg, the retired U.S. Navy rear admiral who stepped down in February as executive director of the Missile Defense Agency (MDA), died April 18 at his home in Alexandria, Va. He was 81 and had leukemia. Altwegg served in the federal government for 64 years and retired Feb. 23 after serving as the MDA’s top civilian official since 2008. The Pentagon has yet to name his replacement.

Altwegg graduated from the Naval Academy in 1952 and did tours of duty in the Vietnam and Korean wars before retiring from active duty in 1985. He received numerous awards including the Legion of Merit, Bronze Star and Meritorious Service Medal.

Altwegg is survived by his wife Rosina, a daughter and two grandchildren. A visitation was held April 23 at the Demaine Funeral Home in Alexandria, and he will be buried at Arlington National Cemetery at a date to be determined, the funeral home said.