The Dryden Flight Research Center (DFRC), located inside Edwards Air Force Base, is an aeronautical research center operated by NASA. On March 26, 1976 it was named in honor of the late Hugh L. Dryden, a prominent aeronautical engineer who at the time of his death in 1965 was NASA's deputy administrator. First known as the National Advisory Committee for Aeronautics Muroc Flight Test Unit, the DFRC has also been known as the High-Speed Flight Research Station (1949) and the High-Speed Flight Station (1954). Dryden is NASA's premier site for aeronautical research and operates some of the most advanced aircraft in the world. It is also the home of the Shuttle Carrier Aircraft (SCA), a modified Boeing 747 designed to carry a Space Shuttle orbiter back to Kennedy Space Center if one lands at Edwards. Kevin Petersen is currently the Center's Director. Until 2004, Dryden operated the oldest B-52 Stratofortress bomber, a B-52B model (tail number 008) which had been converted to drop test aircraft, dubbed 'Balls 8.' It dropped a large number of supersonic test vehicles, ranging from the X-15 to its last research program, the hypersonic X-43A, powered by a Pegasus rocket. It was also the last B-52B still flying, but had the fewest flight hours of any existing B-52 bomber. The aircraft was retired and will eventually find a permanent home at the North Gate of Edwards; a fitting location for an aircraft that was arguably the greatest contributor to aerospace and flight test development.