Paul D. Miller was the Chairman of the Board of Alliant Techsystems, Inc. (ATK), an advanced weapon and space systems company, from January 1999 until April 2005 and served as Chief Executive Officer of ATK from January 1999 until October 2004. Prior to retirement from the U.S. Navy in 1994, Admiral Miller served as Commander-in-Chief, U.S. Atlantic Command and NATO Supreme Allied Commander — Atlantic. He served as a director of Huntington Ingalls Industries, Inc., a shipbuilding company from 2012 to April 2017. From 2001 to 2016 he served as a director of Donaldson Company, Inc., a manufacturer of filtration systems. Admiral Miller is a member of our Audit Committee and our Nominating and Governance Committee.​