Retired general joins The SI Organization CHANTILLY, Va., April 17 (UPI) -- A U.S. systems and engineering integration firm has appointed a retired U.S. Air Force general as vice president of its National Security Space business. In the position with The SI Organization, retired Lt. Gen. John T. "Tom" Sheridan will lead the effort to support national security space programs of the intelligence community, military and NASA. "We have known General Sheridan since the early 1990s, when we supported him on critical national defense space projects," said Bill Graham, president and chief executive officer of The SI Organization. We have witnessed firsthand the strength of his engineering talent, his leadership expertise and his ability to bring both together to deliver the mission. Sheridan was commander of the Space and Missile Systems Center, Air Force Space Command, Los Angeles Air Force Base, Calif., when he retired last year. He also served as the Air Force Program executive officer for Space, managing the research, design, development, acquisition and sustainment of satellite, launch and command and control systems. Other roles include deputy director of the National Reconnaissance Office; program executive officer and director for Space Radar; commandant of the Air Command and Staff College; and director of Requirements for Air Force Space Command.