On July 20, 1969, Neil Armstrong and Buzz Aldrin safely descended onto the moon in Apollo 11. It was a frightening moment, with alarms firing and gas lines freezing as the astronauts barreled toward another celestial body for the first time in human history.
The astronauts landed on Mare Tranquillitatis, a dark bluish plain made of ancient lava, and for the next two hours, they explored the moon's surface, collecting rock samples and bouncing about. It was the first of six more manned journeys to the moon between 1969 and 1972. Apollo 13 was the only mission that had to be aborted, with the crew making an emergency re-entry.
In 1972, Apollo 17 was the last manned expedition at a time when U.S. interest in lunar landings was fading fast. We'd been there, and now it was time for the next big space adventure.
But now, half a century later, scientists have a renewed interest in what we can learn from the moon. According to NASA, the moon continues to be a "treasure trove of science," one that might in the future allow for habitation.
