The Moon is Earth's only natural satellite and the fifth largest moon in the solar system. With a diameter of 3,474.8 km, about 27 percent of Earth's, it is unusually large relative to its parent planet; the gravitational interplay between the two bodies raises ocean tides, stabilizes Earth's axial tilt, and slowly lengthens Earth's day. The Moon orbits at an average distance of 384,400 km and is tidally locked, always presenting the same hemisphere to observers on the ground.
It is also the only world beyond Earth that people have visited, and after decades of neglect it has again become the busiest destination in spaceflight. In April 2026 the Artemis II crew flew the first piloted mission beyond low Earth orbit since 1972.[1] Commercial robotic landers funded by NASA are now arriving at a pace of several per year, and China is preparing Chang'e 7, a four-spacecraft expedition to the lunar south pole, for launch in the second half of 2026.[2] Much of this activity converges on a single resource: water ice locked inside permanently shadowed polar craters.
Formation
The leading explanation for the Moon's origin is the giant-impact hypothesis. Roughly 4.5 billion years ago a Mars-sized body, often called Theia, struck the young Earth, and debris from the collision gathered into a disk that coalesced into the Moon. The scenario accounts for the Moon's small iron core, its depletion in water and other volatiles, and the high angular momentum of the Earth-Moon system. Oxygen isotope ratios in Apollo program samples are nearly identical to Earth's, which has pushed researchers toward variants involving a thoroughly mixed debris disk. The infant Moon was covered by a magma ocean; low-density minerals floated to its top and solidified into the pale highland crust visible today.
Physical characteristics
Surface gravity is 1.62 m/s², about one sixth of Earth's. There is no meaningful atmosphere, only a wispy exosphere, so equatorial temperatures swing from roughly 121 °C at local noon to -133 °C at night, and micrometeoroids strike the surface unimpeded. Everything is blanketed by regolith, a layer of fine, abrasive impact debris several meters deep. Two terrains dominate: ancient, heavily cratered highlands, and darker basaltic plains called maria that flooded large impact basins between about 3.8 and 3 billion years ago, mostly on the near side. Seismometers left by Apollo crews recorded moonquakes until 1977, and laser ranging to retroreflectors on the surface shows the Moon receding from Earth by 3.8 cm per year.
Water ice at the poles
Because the Moon's spin axis tilts only about 1.5 degrees, the floors of some polar craters never receive direct sunlight and stay below -230 °C in places, cold enough to trap water for billions of years. Hydrogen signals detected by Lunar Prospector in 1998, followed by a spectral detection of water and hydroxyl by ISRO's Chandrayaan-1 orbiter in 2009, pointed to ice in these cold traps. Direct proof came on October 9, 2009, when the LCROSS mission steered a spent Centaur rocket stage into Cabeus crater near the south pole: the debris plume contained roughly 155 kg of water, about 5.6 percent of the excavated soil by mass.[3]
Ice matters because water is the heaviest consumable a lunar program would otherwise ship from Earth. Split into hydrogen and oxygen, it becomes breathable air and rocket propellant. That is why nearly every major mission now planned, from Artemis landings to Chang'e 7, targets the south polar region.
Luna, Apollo, and the long gap
The Soviet Union opened lunar exploration: Luna 2 struck the surface in September 1959, Luna 3 photographed the far side a month later, and Luna 9 achieved the first soft landing in February 1966. The United States answered with the crewed Apollo program. Apollo 8 orbited the Moon in December 1968, and on July 20, 1969, Apollo 11 landed Neil Armstrong and Buzz Aldrin at Tranquility Base. Six landings through Apollo 17 in December 1972 put twelve astronauts on the surface and returned 382 kg of rock and soil, while Soviet robotic landers scooped up their own samples through Luna 24 in 1976.
Then interest collapsed. No spacecraft visited the Moon between 1976 and 1990, and nothing landed softly again until China's Chang'e 3 in December 2013. Orbiters led the return: Clementine in 1994, Lunar Prospector in 1998, and NASA's Lunar Reconnaissance Orbiter, mapping the surface since 2009. China's Chang'e 5 brought back 1,731 grams of basalt in December 2020, India's Chandrayaan-3 landed in the south polar region in August 2023, and JAXA's SLIM demonstrated precision landing in January 2024.
The current rush
Under NASA's Commercial Lunar Payload Services (CLPS) program, private companies deliver agency instruments for fixed prices. Intuitive Machines' IM-1 made the first commercial soft landing in February 2024, though it tipped onto its side. Firefly Aerospace's Blue Ghost Mission 1 achieved the first fully successful commercial landing on March 2, 2025, operating in Mare Crisium for a complete lunar day.[4] Attempts planned for 2026 include Astrobotic's Griffin, Intuitive Machines' IM-3 at the Reiner Gamma magnetic swirl, a second Blue Ghost aimed at the far side, and a Draper-led lander bound for Schrödinger basin; ispace's second lander, by contrast, crashed in June 2025.[5] Blue Origin's cargo lander Blue Moon MK1 completed thermal vacuum testing at NASA's Johnson Space Center in May 2026 ahead of a south pole delivery attempt later this year.[6]
| Mission | Operator | Timeframe | Target |
|---|---|---|---|
| Blue Ghost Mission 1 | Firefly Aerospace (CLPS) | March 2025 | Mare Crisium (landed successfully) |
| Artemis II | NASA | April 2026 | Crewed lunar flyby (completed) |
| Griffin Mission 1 | Astrobotic (CLPS) | No earlier than July 2026 | South pole |
| Chang'e 7 | CNSA | Second half of 2026 | Shackleton crater rim |
| IM-3 | Intuitive Machines (CLPS) | Second half of 2026 | Reiner Gamma |
| Blue Ghost Mission 2 | Firefly Aerospace (CLPS) | Late 2026 | Far side |
| Blue Moon MK1 | Blue Origin (CLPS) | 2026 | South pole |
Crewed flight resumed with Artemis II, launched April 1, 2026 on the Space Launch System under the Artemis program. Astronauts Reid Wiseman, Victor Glover, Christina Koch, and Jeremy Hansen looped their Orion capsule around the Moon on April 6, traveled farther from Earth than any previous crew, and splashed down on April 10 after ten days.[1] NASA plans Artemis III in 2027 as an Earth-orbit rendezvous and docking test with lander hardware, followed by Artemis IV, targeted for 2028 as the first crewed landing at the lunar south pole.[7]
China's Chang'e 7, built by the China National Space Administration and now at the Wenchang spaceport, combines an orbiter, a lander, a rover, and a legged hopper designed to fly into permanently shadowed craters, drill, and analyze ice with a mass spectrometer. Launch is expected around August 2026, with the landing targeted near the illuminated rim of Shackleton crater.[2][8] China has also stated its intent to land astronauts before 2030.
Far side science
The far side is not dark (both hemispheres receive equal sunlight) but it is different: its crust is thicker and it carries almost no maria. It hosts the South Pole-Aitken basin, an impact scar roughly 2,500 km across, the largest confirmed in the solar system. China's Chang'e 4 made the first far side landing on January 3, 2019, in Von Kármán crater, and Chang'e 6 returned 1,935 grams of South Pole-Aitken material in June 2024, the first samples from the far hemisphere; both depended on Queqiao relay satellites because the Moon blocks direct radio contact. The far side is also shielded from Earth's radio chatter, which makes it prized ground for low-frequency radio astronomy. Blue Ghost Mission 2 is slated to deliver a pathfinder radio astronomy payload there in late 2026 while placing a communications relay, built with European Space Agency involvement, into lunar orbit.[5]
Future bases and resources
NASA's Artemis Base Camp concept and the China-led International Lunar Research Station both envision durable south pole infrastructure in the 2030s. NASA has contracted SpaceX's Starship lander for the first Artemis landing and Blue Origin's larger Blue Moon MK2 for a later mission.[7] Long-term plans depend on living off the land: cracking ice into propellant, extracting oxygen from regolith, and building shelter from lunar soil. The obstacles are concrete ones: 14-day nights, abrasive dust that degrades seals and equipment, radiation, and unproven mining economics. Helium-3, often cited as a lunar prize, remains speculative because no reactor exists that could burn it. Compared with Mars, though, the Moon is three days away, and that proximity keeps it the proving ground for everything meant to go deeper.
References
- NASA Welcomes Record-Setting Artemis II Moonfarers Back to Earth - NASA.
- China's Chang'e-7 arrives at spaceport for lunar south pole exploration mission - SpaceNews.
- LCROSS - Wikipedia.
- Blue Ghost Lander Successfully Completes Historic Lunar Mission - Scientific American.
- Moon rush: These private spacecraft will attempt lunar landings in 2026 - Space.com.
- Blue Origin Moon Lander Completes Testing at NASA Vacuum Chamber - NASA.
- NASA Marches Toward Artemis III Mission in 2027, Names Crew Members - NASA.
- Hopping robot will hunt for moon water on China's Chang'e 7 lunar mission in 2026 - Space.com.
