First landing on the far side of the Moon

The first spacecraft to successfully land on the far side of the Moon is Chang'e 4, operated by the China National Space Administration (CNSA), which touched down on the lunar surface in the southern part of the Von Kármán Crater at 02:26 (UTC) on 3 January 2019.

Chang'e 4 was launched by a Long March 3B rocket at 18:23 (UTC) on 7 December 2018 and entered lunar orbit five days later. The lander is outfitted with several scientific payloads, including astronomical instruments and a sealed biosphere containing silkworm eggs and seeds. The stationary lander is also carrying a small solar-powered rover (not yet given an official name), which will be deployed at a later date. The goals of the mission are to study the conditions on the far side of the Moon, and to see how astronomical observations differ when isolated from the Earth.

Deploying a lander on the far side of the Moon is a significantly more complex and challenging task than doing the same on the near side. The Moon is "tidally locked", meaning that it rotates slowly as it moves through its orbit. As a result, the same section of its surface (the "near side") is always facing towards Earth while the opposite side (the "far side") faces out into space.

To operate the Chang'e 4 lander, CNSA had to first come up with a way of getting a radio signal to the far side of the Moon. To achieve this, Chinese engineers designed and built a relay satellite, called Queqiao ("Magpie bridge", a reference to a Chinese folk tale), which was launched into an orbit beyond the Moon on 21 May 2018.

The Chang'e 4 lander and rover are, in fact, the unused back-up hardware from China's 2013 Chang'e 3 mission, upgraded and fitted with a new sensor payload. (This re-use of older components is actually fairly common in space science – NASA's Mars 2020 mission uses several pieces of back-up hardware from the Curiosity rover).

Assuming everything goes to plan, CNSA intend to follow up this mission with an even more ambitious sample-return mission – called Chang'e 5 – in around a year's time. This will place a lander on the surface of the Moon, scoop up some lunar soil and rock, then return it to Earth in a sealed capsule.

Chang'e 4 is not the first man-made object to impact the far side of the Moon, but it is the first to do so in a controlled and survivable way. NASA's 1962 Ranger 4 probe impacted on the far side of the Moon, but its systems had failed completely several days earlier. No data was returned from the mission.