 Complete the following phrase:  Prior to his appointment as Center Director, Littles served as NASA Associate Administrator for the Office of Space Flight 1994-1996. Littles began his NASA career in 1967 when he worked as an engineer in Marshalls former Propulsion and Vehicle Engineering Directorate. He worked in various capacities at the Marshall Center, including Science Engineering Director 1988-1989 and Center Deputy Director 1989-1994 before transferring to NASA Headquarters in 1994, as Chief Engineer. Littles was involved in the redesign of the space shuttle booster rockets, blamed for the 