Finally here, lost in time. And tonight, more than 40 years later, found. Reporter: We've long been fascinated by the moon, admiring it from a distance, until that summer night. JULY 16th, 1969, AND THAT Historic mission to the moon. 10, 9 -- ignition sequence starts. Reporter: "Apollo 11" lifts off from cape canaveral, carrying astronauts neil armstrong and buzz aldrin. Four days later, and those words. That's one small step for man, one giant leap for mankind. Reporter: He would spend two hours, 21 minutes, walking in the lunar dust, raising the american flag. Later, we learned armstrong thought landing on the moon, not walking on it, was far more challenging. More forward. Just into the right a little. Reporter: But he also did something else. He collected 852 pounds of lunar dust, lunar rocks. And now, more than 40 years later, another small step and a giant find, in a california storage closet. Some of that lunar dust, gathering dust. All those years ago, samples had been sent to 150 different labs. They were thought to have been sent back to nasa. So, nasa is over the moon tonight, just like the lab worker who found them. 20 vials, from the moon, from 1969. Vacuum sealed in a glass jar container. The handwritten labels there, you can see, "apollo 11," rock dust. And that date, the 24th of july. Now returned nearly 43 years later, and reminding us all of that moment on the moon.

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