Space station commander Scott Kelly, whose identical twin brother Mark Kelly is married to Giffords and is also an astronaut, led NASA in a moment of silence Monday as part of the national observance for all the victims of Saturday's shooting.
From August 1998 to February 2000, Myers was commander-in-chief of the North American Aerospace Defense Command and U.S. Space Command, and commander of Air Force Space Command, responsible for U.S. defense via space and intercontinental ballistic missile operations.