Luna 20 was to conduct the mission that Luna 18 was unable to complete: obtain a soil sample from the lunar highlands and bring it to Earth for comparison with Luna 16's sample from a site that was thought to be geologically different.

The primary mission objectives of the second crewed lunar landing included an extensive series of lunar exploration tasks by the lunar module, or LM, crew, as well as the deployment of the Apollo Lunar Surface Experiments Package, or ALSEP, which was to be left on the moon's surface to gather

The primary objective of Apollo 11 was to complete a national goal set by President John F. Kennedy on May 25, 1961: perform a crewed lunar landing and return to Earth.

Luna 15 was the second attempt by the Soviet Union to recover and return lunar soil back to Earth. Launched just three days before the Apollo 11 mission, Luna 15 raced to beat the crew to the Moon. In a race to reach the Moon and return to Earth, the

The Apollo 10 mission encompassed all aspects of an actual crewed lunar landing, except the landing. It was the first to operate around the Moon. Objectives included a scheduled eight-hour lunar orbit of the separated lunar module, or LM, and descent to about nine miles off the Moon's surface before