The Moon was first visited by the Soviet Union’s uncrewed Luna 1 and 2 in 1959, and, as of April 2019, seven nations have followed. The U.S. sent three classes of robotic missions to prepare the way for human exploration: the Rangers (1961–1965) were impact probes, the Lunar Orbiters (1966–1967) mapped the surface to find landing sites, and the Surveyors (1966–1968) were soft landers.
The first human landing on the Moon was on July 20, 1969. During the Apollo missions of 1969–1972, 12 American astronauts walked on the Moon and used a Lunar Roving Vehicle to travel on the surface and extend their studies of soil mechanics, meteoroids, lunar ranging, magnetic fields, and solar wind. The Apollo astronauts brought back 382 kilograms (842 pounds) of rock and soil to Earth for study.
After a long hiatus, lunar exploration resumed in the 1990s with the U.S. robotic missions Clementine and Lunar Prospector. Results from both missions suggested that water ice might be present at the lunar poles, but a controlled impact of the Prospector spacecraft produced no observable water. The U.S. began a new series of robotic lunar missions with the joint launch of the Lunar Reconnaissance Orbiter (LRO) and Lunar Crater Observation and Sensing Satellite (LCROSS) in 2009. In 2011, a pair of repurposed spacecraft began the ARTEMIS (Acceleration, Reconnection, Turbulence, and Electrodynamics of the Moon’s Interaction with the Sun) mission. In 2012, the Gravity Recovery and Interior Laboratory (GRAIL) twin spacecraft studied the Moon’s gravity field and produced the highest-resolution gravity field map of any celestial body.
In March 2019, NASA announced plans to send U.S. astronauts back to the surface of the Moon.
The European Space Agency, Japan, China and India all have sent missions to explore the Moon. China has landed two rovers on the surface, including the first-ever landing on Moon's far side in 2019. In another first, a private company from Israel sent a spacecraft to land on the Moon in April 2019. Israel's Beresheet successfully orbited the Moon, but was lost during a landing attempt.