NASA Administrator Sean O'Keefe, left, learned about the Mach 10 X-43 research vehicle from manager Joel Sitz during a visit to the NASA Dryden Flight Research Center, Edwards, California, January 31, 2002 NASA Administrator Sean O'Keefe left, learned about the Mach 10 X-43 research vehicle from manager, Joel Sitz during O'Keefe's visit to the NASA Dryden Flight Research Center, Edwards, California, January 31, 2002.