The 2008 TIME 100

Mike Griffin, 58, had wanted to be administrator of NASA since the inception of the agency. To him, the appeal of the job was never about position or title but about the fact that space fired his imagination. It still does, and now, thanks to him, manned exploration of the moon and Mars is becoming a real possibility.

With advanced degrees in half a dozen fields and experience managing military and civilian space programs, he was the ideal choice when President George W. Bush needed a new NASA administrator to manage the moon-Mars initiative he announced in 2004. Mike made it immediately clear that he would do things differently. With four simple words—"Just call me Mike"—he began restructuring NASA into the kind of openly communicative and inspired organization it once was. A true engineer in the broadest sense, he understands systems—whether they are rockets, satellites, airplanes or the U.S. Congress. Not only can he quote you the history of a technical concept, but he can also derive the theory for you.

NASA is dead serious about having footprints back on the moon by 2020, and even now the metal is being cut on the new ships that will fly those missions. Mike Griffin—a true rocket scientist—is precisely the kind of person who will see that the job gets done.

Ivins is an astronaut and a veteran of five space-shuttle missions