He was named NASA’s Program Manager for Mars exploration in April 2000 after the agency had suffered two consecutive, very public failures in the previous year. In the summer of 2000, he helped re-plan the Program as a chain of scientifically, technologically and operationally interrelated missions with a spacecraft launched to Mars every two years. He led the Program for the next five years, a span of time that included the successful landing of the Mars Exploration Rovers, Spirit and Opportunity.