Apollo Program:

Project Apollo's goals went beyond landing Americans on the Moon and returning them safely to Earth:

Apollo was a three-part spacecraft: the command module (CM), the crew's quarters and flight control section; the service module (SM) for the propulsion and spacecraft support systems (when together, the two modules are called CSM); and the lunar module (LM). The CM and LM would separate after lunar orbit insertion. One crew member would stay in the CM, which would orbit the Moon, while the other two astronauts would take the LM down to the lunar surface. After exploring the surface, setting up experiments, taking pictures, collecting rock samples, etc., the astronauts would return to the CM for the journey back to Earth.

Six of the missions (Apollos 11, 12, 14, 15, 16, and 17) landed humans on the Moon and bought them safely back to Earth. Apollos 7 and 9 were Earth orbiting missions to test the Command and Lunar Modules, and did not return lunar data. Apollos 8 and 10 tested various components while orbiting the Moon, and returned photography of the lunar surface. Apollo 13 did not land on the Moon due to a malfunction, but also returned photographs. The six missions that landed on the Moon returned a wealth of scientific data and almost 400 kilograms of lunar samples. Experiments included soil mechanics, meteoroids, seismic, heat flow, lunar ranging, magnetic fields, and solar wind experiments.

Excerpt from the Encyclopedia Britannica without permission.