In 2005, Dr. Chang Díaz completed a 25 year career as a NASA astronaut where he became a veteran of 7 space missions. He has logged over 1,600 hours in space, including 19 hours on three space walks. In 1994, in conjunction with astronaut training at NASA, he founded and directed the Advanced Space Propulsion Laboratory (ASPL) at the Johnson Space Center where he managed a multi-center research team developing advanced plasma rocket propulsion concepts.