Tranquility Base in the context of Buzz Aldrin

Apollo 11 was the first spaceflight to land humans on the Moon, conducted by NASA from July 16 to 24, 1969. Commander Neil Armstrong and Lunar Module Pilot Edwin "Buzz" Aldrin landed the Lunar Module Eagle on July 20 at 20:17 UTC, and Armstrong became the first person to step onto the surface about six hours later, at 02:56 UTC on July 21. Aldrin joined him 19 minutes afterward, and together they spent about two and a half hours exploring the site they had named Tranquility Base upon landing. They collected 47.5 pounds (21.5 kg) of lunar material to bring back to Earth before re-entering the Lunar Module. In total, they were on the Moon’s surface for 21 hours, 36 minutes before returning to the Command Module Columbia, which remained in lunar orbit, piloted by Michael Collins.

Apollo 11 was launched by a Saturn V rocket from Kennedy Space Center in Florida, on July 16 at 13:32 UTC (9:32 am EDT, local time). It was the fifth crewed mission of the Apollo program. The Apollo spacecraft consisted of three parts: the command module (CM), which housed the three astronauts and was the only part to return to Earth; the service module (SM), which provided propulsion, electrical power, oxygen, and water to the command module; and the Lunar Module (LM), which had two stages—a descent stage with a large engine and fuel tanks for landing on the Moon, and a lighter ascent stage containing a cabin for two astronauts and a small engine to return them to lunar orbit.

Moltke is a lunar impact crater near the southern edge of the Mare Tranquillitatis. It is a small, bowl-shaped crater surrounded by a bright halo of higher-albedo material. Just to the south lies the rille system named Rimae Hypatia. These follow a course running roughly east-southeast to west-northwest, and have a length of approximately 180 kilometers.

About 50 kilometers to the northwest of this crater is Tranquility Base, the 1969 landing site of Apollo 11.

Lunar Module Eagle (LM-5) is the spacecraft that served as the crewed lunar lander of Apollo 11, which was the first mission to land humans on the Moon. It was named after the bald eagle, which was featured prominently on the mission insignia. It flew from Earth to lunar orbit on the command module Columbia, and then was flown to the Moon on July 20, 1969, by astronaut Neil Armstrong with navigational assistance from Buzz Aldrin. Eagle's landing created Tranquility Base, named by Armstrong and Aldrin and first announced upon the module's touchdown.

The name of the craft gave rise to the phrase "The Eagle has landed", the words Armstrong said upon Eagle's touchdown.

A moonbase (or lunar base) is a human outpost on or below the surface of the Moon. More than a mere site of activity or temporary camp, moonbases are extraterrestrial bases, supporting robotic or human activity, by providing surface infrastructure. Missions to the Moon have realized single-mission bases, (Tranquility Base being the first), as well as some small permanent infrastructure like lunar laser ranging installations.

Plans for establishing moonbases, with surface or sub-surface research stations, have been proposed and are actively pursued nationally and increasingly internationally. As of 2025, the two most advanced projects to set up moonbases have been pursued multilaterally as part of the US-led Artemis program, with its planned Artemis Base Camp and as the China-led International Lunar Research Station. A broader, international infrastructure has been envisioned with the so-called Moon Village concept, and a general international regulatory regime for lunar activity has been called for by the 1979 signed Moon Treaty, and advocated for with an implementation agreement since 2020.

Mare Tranquillitatis /træŋˌkwɪlɪˈteɪtɪs/ (Latin for Sea of Tranquillity or Sea of Tranquility) is a lunar mare that sits within the Tranquillitatis basin on the Moon. It contains Tranquility Base, the first location on another celestial body to be visited by humans.

The mare material within the basin consists of basalt formed in the intermediate to young age group of the Upper Imbrian epoch. The surrounding mountains are thought to be of the Lower Imbrian epoch, but the actual basin is probably Pre-Nectarian. The basin has irregular margins and lacks a defined multiple-ringed structure. The irregular topography in and near this basin results from the intersection of the Tranquillitatis, Nectaris, Crisium, Fecunditatis, and Serenitatis basins with two throughgoing rings of the Procellarum basin. Palus Somni, on the northeastern rim of the mare, is filled with the basalt that spilled over from Tranquillitatis.