The Ranger program was a series of uncrewed space missions by the United States in the 1960s whose objective was to obtain the first close-up images of the surface of the Moon. The Ranger spacecraft were designed to take images of the lunar surface, transmitting those images to Earth until the spacecraft were destroyed upon impact. A series of mishaps, however, led to the failure of the first six flights. At one point, the program was called "shoot and hope". Congress launched an investigation into "problems of management" at NASA Headquarters and Jet Propulsion Laboratory. After two reorganizations of the agencies, Ranger 7 successfully returned images in July 1964, followed by two more successful missions.
Surveyor 2 was to be the second lunar lander in the uncrewed American Surveyor program to explore the Moon. After launch on September 20, 1966 a mid-course correction failure resulted in the spacecraft losing control. Contact was lost with the spacecraft at 9:35 UTC, September 22.
A lander is a spacecraft that descends towards, then comes to rest on the surface of an astronomical body other than Earth. In contrast to an impact probe, which makes a hard landing that damages or destroys the probe upon reaching the surface, a lander makes a soft landing after which the probe remains functional.
The far side of the Moon is the lunar hemisphere that always faces away from Earth, opposite to the near side, because of synchronous rotation in the Moon's orbit. Compared to the near side, the far side's terrain is rugged, with a multitude of impact craters and relatively few flat and dark lunar maria ("seas"), giving it an appearance closer to other barren places in the Solar System such as Mercury and Callisto. It has one of the largest craters in the Solar System, the South Pole–Aitken basin. The hemisphere has sometimes been called the "dark side of the Moon", where "dark" means "unknown" instead of "lacking sunlight" – each location on the Moon experiences two weeks of sunlight while the opposite location experiences night.
A Moon landing or lunar landing is the arrival of a spacecraft on the surface of the Moon, including both crewed and robotic missions. The first human-made object to touch the Moon was Luna 2 in 1959.
A lunar lander or Moon lander is a spacecraft designed to land on the surface of the Moon. As of 2024, the Apollo Lunar Module is the only lunar lander to have ever been used in human spaceflight, completing six lunar landings from 1969 to 1972 during the United States' Apollo Program. Several robotic landers have reached the surface, and some have returned samples to Earth.
A sample-return mission is a spacecraft mission to collect and return samples from an extraterrestrial location to Earth for analysis. Sample-return missions may bring back merely atoms and molecules or a deposit of complex compounds such as loose material and rocks. These samples may be obtained in a number of ways, such as soil and rock excavation or a collector array used for capturing particles of solar wind or cometary debris. Nonetheless, concerns have been raised that the return of such samples to planet Earth may endanger Earth itself.
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 September 14, 1959. Prior to that the only available means of exploration had been observation 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 using it.
The following outline is provided as an overview of and topical guide to space exploration.
The Lunar Atmosphere and Dust Environment Explorer was a NASA lunar exploration and technology demonstration mission. It was launched on a Minotaur V rocket from the Mid-Atlantic Regional Spaceport on September 7, 2013. During its seven-month mission, LADEE orbited the Moon's equator, using its instruments to study the lunar exosphere and dust in the Moon's vicinity. Instruments included a dust detector, neutral mass spectrometer, and ultraviolet-visible spectrometer, as well as a technology demonstration consisting of a laser communications terminal. The mission ended on April 18, 2014, when the spacecraft's controllers intentionally crashed LADEE into the far side of the Moon, which, later, was determined to be near the eastern rim of Sundman V crater.
The Lunar Reconnaissance Orbiter (LRO) is a NASA robotic spacecraft currently orbiting the Moon in an eccentric polar mapping orbit. Data collected by LRO have been described as essential for planning NASA's future human and robotic missions to the Moon. Its detailed mapping program is identifying safe landing sites, locating potential resources on the Moon, characterizing the radiation environment, and demonstrating new technologies.
Strictly speaking, a satellite collision is when two satellites collide while in orbit around a third, much larger body, such as a planet or moon. This definition is typically loosely extended to include collisions between sub-orbital or escape-velocity objects with an object in orbit. Prime examples are the anti-satellite weapon tests. There have been no observed collisions between natural satellites, but impact craters may show evidence of such events. Both intentional and unintentional collisions have occurred between man-made satellites around Earth since the 1980s. Anti-satellite weapon tests and failed rendezvous or docking operations can result in orbital space debris, which in turn may collide with other satellites.
Chang'e 5-T1 was an experimental robotic spacecraft that was launched to the Moon on 23 October 2014, by the China National Space Administration (CNSA) to conduct atmospheric re-entry tests on the capsule design planned to be used in the Chang'e 5 mission. As part of the Chinese Lunar Exploration Program, Chang'e 5, launched in 2020, was a Moon sample return mission. Like its predecessors, the spacecraft is named after the Chinese Moon goddess Chang'e. The craft consisted of a return vehicle capsule and a service module orbiter.
The following outline is provided as an overview of and topical guide to the Moon:
