A half-century ago, as the world watched in awe as Neil Armstrong took that "one small step" into history on the surface of the moon, a voice from Houston was his constant connection to humanity back on Earth. Earlier, however, as the landing craft neared its destination, that voice had called "60 seconds," to warn the Apollo 11 astronauts - Armstrong, Buzz Aldrin and Michael Collins - that they had only one minute's worth of fuel to land, or they would have to abort the mission. That voice