Chinese Lunar Exploration Program

Chang'e 1

The Chang'e Program began with the launch of the orbital probe Chang'e 1 on 24 October 2007. This first mission was tasked with creating a 3D map of the lunar surface. Over the course of 589 orbits, Chang'e 1 created the highest resolution map of the Moon with complete coverage, providing data invaluable to future soft landings there. 

The spacecraft also carried with it 32 Chinese songs to transmit back to Earth upon insertion into lunar orbit, which was achieved on 5 November 2007. This action followed in the footsteps of Dong Fang Hong 1, China's first satellite, broadcasting music of the same name for 20 days while in orbit.

Chang'e 2

Chang'e 2 launched on 1 October 2010. The probe used for the mission was the backup of the one used for Chang'e 1, with some additional technical modifications. This included a higher resolution camera, which, in combination with the probe's lower flight altitude, allowed for more detailed imaging of the lunar surface. In preparation for the planned soft landing of Chang'e 3, Chang'e 2 provided images of the intended landing site in the Sinus Iridum, selected for its relatively flat terrain and geological features.

The probe orbited the Moon for 8 months before heading off towards the Earth-Sun L2 Lagrange point, about 1.5 million kilometres away from the Earth. After a flyby of the asteroid 4179 Toutatis in 2012, the probe has continued to journey further out into space, becoming China's first interplanetary probe. Contact was lost in 2014, but the probe is expected to return to within Earth's vicinity around the end of this decade.

Chang'e 3

Chang'e 3 was launched on 2 December 2013 and became the first Chinese mission to soft land on the lunar surface. This made China the third country to land on the Moon, with the last lunar landing being nearly 40 years prior with Luna 24 in 1976. Though Sinus Iridum was the planned landing site, the spacecraft actually touched down in the Mare Imbrium, the region which Sinus Iridum shoots off from.

The mission also delivered the lunar rover Yutu to the Moon's surface. Its main objective, aside from the achievement of its own presence on the Moon, was to study the lunar geology. A ground-penetrating radar aboard Yutu was used to detect the structure and thickness of the lunar soil and crust to depths never reached before.

Chang'e 4

The program's second lunar lander was launched on 7 December 2018, bringing with it another first - this time, being the first soft landing on the lunar far side. This feat earned the mission's team a myriad of awards and recognition, including the Gold Medal by the Royal Aeronautical Society and the World Space Award from the International Astronautical Federation.

Similarly to Chang'e 2 (which was initially a flight spare), Chang'e 4 acted as the backup spacecraft to Chang'e 3 and was adapted based on the information gained from that previous mission. Due to tidal locking, the far side of the Moon never faces the Earth, so communications between the two need to be facilitated by an orbiting spacecraft. For Chang'e 4, this task is carried out by the Queqiao relay satellite, launched about six months prior.

Chang'e 4 carried a biosphere experiment to test how a selection of organisms would grow and adapt to the lunar environment. This included yeast, fruit fly eggs, potato seeds and cotton seeds, alongside the water, soil and air needed to sustain them. This combination of organisms were designed to act together as a self-sustaining mini ecosystem. The cotton seeds eventually sprouted, marking the first plants to sprout on the Moon, though they died a day later under the harsh lunar conditions.

The mission also included China's second lunar rover, Yutu 2, which remains operational to this day.

Chang'e 5

Chang'e 5 ushered in the sample return phase of the Chang'e program, with the goal of becoming China's first mission to bring Moon samples back to the Earth. It launched on 23 November 2020 and returned to Earth just over two weeks later, bringing with it roughly 1.7 kilograms of lunar material. This was slightly below the anticipated 2 kilograms, due to some unexpected resistance experienced by the lander's drill while excavating the material. 

The spacecraft touched down near the Mons Rümker, a volcanic region in the Oceanus Procellarum. This landing site was selected because it was believed to hold relatively young material, due to a supposed volcanic event covering the underlying soil and rock. Analysis of the samples returned to Earth proved these suspicions to be correct - they were found to be roughly 2 billion years old, significantly younger than the 3 to 4.5 billion year old samples collected during the Apollo missions.

Chang'e 6

Chang'e 6 launched on 3 May 2024, and will be China's second Moon sample return mission. It will attempt to collect and bring to Earth the first samples from the lunar far side. Specifically, the mission aims to collect material from the Apollo crater, a large impact crater within the South Pole–Aitken basin. It is hoped that there may be lunar mantle material (from the interior of the Moon, just below the crust) available in this region, exposed by the original impact that created the surface feature. Study of the lunar mantle may reveal more details about the Moon's formation, which could act as a proxy for the development of rocky objects in our Solar System at large. 

The Queqiao 2 satellite was launched on 20 March 2024. Compared to its predecessor, this satellite features technological enhancements that improve its ability to communicate with ground stations back on Earth. It is also expected to operate for longer from its more stable elliptical orbit, facilitating communications for further missions in the Chang'e Program.