NASA’s Marshall Space Flight Center Director Joseph Pelfrey resigned on Thursday, citing the need for agency leadership to move forward with a team suited to returning humans to the moon. Pelfrey will collaborate with NASA leaders to explore new ways to serve the space program and the nation. He oversaw 7,000 employees and a $5 billion annual budget at the Huntsville, Alabama center, which now employs over 6,000 people. His resignation was unexpected, and an all-hands meeting was canceled. NASA confirmed the departure and will hold an open competition to appoint the next permanent director. Budget constraints and past staff reductions have affected the agency.