As NASA Associate Administrator George Mueller put it, "Apollo9 was as successful a flight as any of us could ever wish for, as well as being as successful as any of us have ever seen." Gene Kranz called Apollo9 "sheer exhilaration". Apollo Program Director Samuel C. Phillips stated, "in every way, it has exceeded even our most optimistic expectations." Apollo11 astronaut Buzz Aldrin stood in Mission Control as "Spider" and "Gumdrop" docked after their separate flights, and with the docking, according to Andrew Chaikin, "Apollo9 had fulfilled all its major objectives. At that moment, Aldrin knew Apollo10 would also succeed, and that he and Armstrong would attempt to land on the Moon. On March 24, NASA made it official."