Buzz Aldrin in the context of Apollo Program

A space suit (or spacesuit) is an environmental suit used for protection from the harsh environment of outer space, mainly from its vacuum as a highly specialized pressure suit, but also its temperature extremes, as well as radiation and micrometeoroids. Basic space suits are worn as a safety precaution inside spacecrafts in case of loss of cabin pressure. For extravehicular activity (EVA) more complex space suits are worn, featuring a portable life support system.

Pressure suits are in general needed at low pressure environments above the Armstrong limit, at around 19,000 m (62,000 ft) above Earth. Space suits augment pressure suits with complex system of equipment and environmental systems designed to keep the wearer comfortable, and to minimize the effort required to bend the limbs, resisting a soft pressure garment's natural tendency to stiffen against the vacuum. A self-contained oxygen supply and environmental control system is frequently employed to allow complete freedom of movement, independent of the spacecraft.

A planetary surface is where the solid or liquid material of certain types of astronomical objects contacts the atmosphere or outer space. Planetary surfaces are found on solid objects of planetary mass, including terrestrial planets (including Earth), dwarf planets, natural satellites, planetesimals and many other small Solar System bodies (SSSBs). The study of planetary surfaces is a field of planetary geology known as surface geology, but also a focus on a number of fields including planetary cartography, topography, geomorphology, atmospheric sciences, and astronomy. Land (or ground) is the term given to non-liquid planetary surfaces. The term landing is used to describe the collision of an object with a planetary surface and is usually at a velocity in which the object can remain intact and remain attached.

In differentiated bodies, the surface is where the crust meets the planetary boundary layer. Anything below this is regarded as being sub-surface or sub-marine. Most bodies more massive than super-Earths, including stars and giant planets, as well as smaller gas dwarfs, transition contiguously between phases, including gas, liquid, and solid. As such, they are generally regarded as lacking surfaces.

The Apollo program, also known as Project Apollo, was the United States human spaceflight program led by NASA, which landed the first humans on the Moon in 1969. Apollo was conceived during Project Mercury and executed after Project Gemini. It was conceived in 1960 as a three-person spacecraft during the presidency of Dwight D. Eisenhower. Apollo was later dedicated to President John F. Kennedy's national goal for the 1960s of "landing a man on the Moon and returning him safely to the Earth" in an address to the U.S. Congress on May 25, 1961.

Kennedy's goal was accomplished on the Apollo 11 mission, when astronauts Neil Armstrong and Buzz Aldrin landed their Apollo Lunar Module (LM) on July 20, 1969, and walked on the lunar surface, while Michael Collins remained in lunar orbit in the command and service module (CSM), and all three landed safely on Earth in the Pacific Ocean on July 24. Five subsequent Apollo missions also landed astronauts on the Moon, the last, Apollo 17, in December 1972. In these six spaceflights, twelve people walked on the Moon.

Space exploration is the physical investigation of outer space by uncrewed robotic space probes and through human spaceflight.

While the observation of objects in space, known as astronomy, predates reliable recorded history, it was the development of large and relatively efficient rockets during the mid-twentieth century that allowed physical space exploration to become a reality. Common rationales for exploring space include advancing scientific research, national prestige, uniting different nations, ensuring the future survival of humanity, and developing military and strategic advantages against other countries.

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.

The physical exploration of the Moon began when Luna 2, a space probe launched by the Soviet Union, made a deliberate impact on the surface of the Moon on 14 September, 1959. Prior to that the only available means of lunar exploration had been observations from Earth. The invention of the optical telescope brought about the first leap in the quality of lunar observations. Galileo Galilei is generally credited as the first person to use a telescope for astronomical purposes, having made his own telescope in 1609. The mountains and craters on the lunar surface were among his first observations.

Human exploration of the Moon since Luna 2 has consisted of both crewed and uncrewed missions. NASA's Apollo program has been the only program to successfully land humans on the Moon, which it did six times on the near side in the late 20th century. The first human landing took place in 1969, when the Apollo 11 astronauts Buzz Aldrin and Neil Armstrong touched down on the surface in the region of Mare Tranquillitatis, leaving scientific instruments upon the mission's completion and returning lunar samples to Earth. All lunar missions had taken place on the lunar near side until the first soft landing on the far side of the Moon was made by the CNSA robotic spacecraft Chang'e 4 in early 2019, which successfully deployed the Yutu-2 robotic lunar rover. On 25 June 2024, CNSA's Chang'e 6 conducted the first lunar sample return from the far side of the Moon.

Footprints are the impressions or images left behind by a person walking or running. Hoofprints and pawprints are those left by animals with hooves or paws rather than feet, while "shoeprints" is the specific term for prints made by shoes. They may either be indentations in the ground or something placed onto the surface that was stuck to the bottom of the foot. A "trackway" is a set of footprints in soft earth left by a life-form; animal tracks are the footprints, hoofprints, or pawprints of an animal.

Footprints can be followed when tracking during a hunt or can provide evidence of activities. Some footprints remain unexplained, with several famous stories from mythology and legend. Others have provided evidence of prehistoric life and behaviours.

Lunar regolith is the unconsolidated material found on the surface of the Moon and in the Moon's tenuous atmosphere. Lunar soil typically refers to only the finer fraction of lunar regolith, which is composed of grains 1 cm in diameter or less, but is often used interchangeably. Lunar soil differs substantially in properties from terrestrial soil. Lunar dust is even finer regolith than lunar soil, with grain sizes less than one millimeter.

Lunar regolith is primarily the result of mechanical weathering. Continual meteoric impacts and bombardment by solar and interstellar charged atomic particles of the lunar surface over billions of years ground the basaltic and anorthositic rock, the regolith of the Moon, into progressively finer material. This situation contrasts fundamentally to terrestrial soil formation, mediated by the presence of molecular oxygen (O₂), humidity, atmospheric wind, and a robust array of contributing biological processes.

NASA Astronaut Group 3 (nicknamed "The Fourteen") was a group of fourteen astronauts selected by NASA for the Gemini and Apollo programs. The Apollo spacecraft had a crew of three, so more astronauts were required. Their selection was announced in October 1963. Four died in training accidents before they could fly in space: Theodore Freeman, Charles Bassett and C. C. Williams in air crashes, and Roger Chaffee in the Apollo 1 fire. All of the surviving ten flew Apollo missions. Five also flew Gemini missions: David Scott, Gene Cernan, Michael Collins, Richard Gordon and Buzz Aldrin. Aldrin, Alan Bean, Cernan and Scott walked on the Moon, and Bill Anders, Collins and Gordon orbited the Moon but did not land.

Seven were from the United States Air Force (Aldrin, Anders, Bassett, Collins, Donn Eisele, Freeman and Scott), four from the United States Navy (Bean, Cernan, Chaffee and Gordon), one (Williams) was from the United States Marine Corps, and two (Walter Cunningham and Rusty Schweickart) were selected as civilians, although both had prior military experience. Like the two groups before them, all members of the group were male and white. All were married except for Williams, who became the first bachelor astronaut. Group 3 was the first to waive the requirement that candidates have a test pilot background, with 1,000 hours of jet aircraft experience accepted as a substitute. This applied to Aldrin, Anders, Cernan, Chaffee, Cunningham and Schweickart; all the others were test pilots. On average, its members were younger, slightly taller and heavier than those of the previous two groups, and better educated.

The DC Towers, also known as the Donau City Towers, is a mixed-use skyscraper complex in the Donaustadt District of Vienna, Austria. The towers were designed by French architect Dominique Perrault. Werner Sobek AG was responsible for the structural engineering as well as the facade and height access planning of DC Tower 1.

DC Tower 1, the tallest skyscraper in Austria at 220 metres (720 ft) or 250 metres (820 ft) including the antenna spire, was officially finished with an opening ceremony on 26 February 2014 attended by architect Perrault and former astronaut Buzz Aldrin. Due to the 2008 financial crisis, ground breaking was delayed several times. Eventually, construction was started on 17 June 2010.

Michael Collins (October 31, 1930 – April 28, 2021) was an American astronaut who flew the Apollo 11 command module Columbia around the Moon in 1969 while his crewmates, Neil Armstrong and Buzz Aldrin, made the first crewed landing on the surface. He was also a test pilot and major general in the U.S. Air Force Reserve.

Born in Rome, where his father was serving as the U.S. military attaché, Collins graduated in the Class of 1952 from the United States Military Academy. He followed his father, brother, uncle, and cousin into the military. He joined the United States Air Force, and flew F-86 Sabre fighters at Chambley-Bussières Air Base, France. He was accepted into the U.S. Air Force Experimental Flight Test Pilot School at Edwards Air Force Base in 1960, also graduating from the Aerospace Research Pilot School (Class III).

The Lunar Flag Assembly (LFA) was a kit containing a flag of the United States designed to be erected on the Moon during the Apollo program. Six such flag assemblies were planted on the Moon. The nylon flags were hung on telescoping staffs and horizontal bars constructed of one-inch anodized aluminum tubes.

The flags were carried on the outside of the Apollo Lunar Module (LM), most of them on the descent ladder inside a thermally insulated tubular case to protect them from exhaust gas temperatures calculated to reach 2,000 °F (1,090 °C). The assembly was designed and supervised by Jack Kinzler, head of technical services at the Manned Spacecraft Center (MSC) in Houston, Texas. Six of the flags (including one for Apollo 13 which was not planted on the Moon) were ordered from a government supply catalog and measured 3 by 5 feet (0.91 by 1.52 m); the last one planted on the Moon was the slightly larger, 6-foot (1.8 m)-wide flag which had hung in the MSC Mission Operations Control Room for most of the Apollo program.

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.

Tranquility Base (Latin: Statio Tranquillitatis) is the site on the Moon where, in July 1969, humans landed and walked on a celestial body other than Earth for the first time. On July 20, 1969, Apollo 11 crewmembers Neil Armstrong and Buzz Aldrin landed their Apollo Lunar Module Eagle at approximately 20:17:40 UTC. Armstrong exited the spacecraft six hours and 39 minutes after touchdown, followed 19 minutes later by Aldrin. The astronauts spent two hours and 31 minutes examining and photographing the lunar surface, setting up several scientific experiment packages, and collecting 47.5 pounds (21.5 kg) of dirt and rock samples for return to Earth. They lifted off the surface on July 21 at 17:54 UTC. The two named the base, which Armstrong announced when the Lunar Module Eagle landed. It is located in the south-western corner of the dark lunar plain Mare Tranquillitatis ("Sea of Tranquility").

Due to involvement of facilities within the U.S. states of California and New Mexico with the Apollo program, the relevant government bodies in these states have registered Tranquility Base as a historic site associated with the heritage of the respective state: the California State Historical Resources Commission in the California Register of Historical Resources, and the New Mexico Historic Preservation Division of the New Mexico Department of Cultural Affairs in the New Mexico State Register of Cultural Properties site #1946. However, Texas, the U.S. National Park Service, and UNESCO have declined to do so, citing the procedural technicality that it is not located within their borders (which according to common convention don't extend thousands of miles beyond the Earth's surface).

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.

The Apollo program was a United States human spaceflight program carried out from 1961 to 1972 by the National Aeronautics and Space Administration (NASA), which landed the first astronauts on the Moon. The program used the Saturn IB and Saturn V launch vehicles to lift the Command/Service Module (CSM) and Lunar Module (LM) spacecraft into space, and the Little Joe II rocket to test a launch escape system which was expected to carry the astronauts to safety in the event of a Saturn failure. Uncrewed test flights beginning in 1966 demonstrated the safety of the launch vehicles and spacecraft to carry astronauts, and four crewed flights beginning in October 1968 demonstrated the ability of the spacecraft to carry out a lunar landing mission.

Apollo achieved the first crewed lunar landing on the Apollo 11 mission, when Neil Armstrong and Buzz Aldrin landed their LM Eagle in the Sea of Tranquility and walked on the lunar surface, while Michael Collins remained in lunar orbit in the CSM Columbia, and all three landed safely on Earth on July 24, 1969. Five subsequent missions landed astronauts on various lunar sites, ending in December 1972 with 12 men having walked on the Moon and 842 pounds (382 kg) of lunar rocks and soil samples returned to Earth, greatly contributing to the understanding of the Moon's composition and geological history.