'Space can unite a troubled country in troubled times': NASA chief calls for unity 55 years after Apollo 11 moon landing

A bootprint on the surface of the moon, taken by Apollo 11's Buzz Aldrin during the first human moon landing on July 20, 1969.

NASA administrator Bill Nelson is calling for unity among both major U.S. political parties amid the 55th anniversary of the first human moon landing on Saturday (July 20).