Chinese officials said during a briefing on Wednesday that Chang’e-4 will rocket toward the moon in December. CCTV, a state-supervised media outlet, shared an online video of the announcement.
The Chang’e 4 mission was first scheduled for launch in 2015 as part of the Chinese Lunar Exploration Program. The mission, named after the mythical moon goddess Chang’e, is the fourth in an ongoing lunar exploration program. Delays in the mission caused by changes in objectives and design pushed the launch date to the end of 2018.
The landing will be on the lunar far side, an unexplored region of the Moon called South Pole-Aitken Basin, a vast basin in the southern hemisphere of the far side which extends from the South Pole to Aitken crater. While the actual landing site has not been publicized, the proposed landing site is the Von Kármán crater – thought to be the oldest impact feature on the Moon.
As for its geological composition, the crater contains about 10 percent by weight iron oxide (FeO) and 4-5 parts per million of thorium, which has been used as a replacement for uranium as nuclear fuel on several thorium reactors.
Chang’e 4 repurposed
After China’s successful Chang’e 3 mission which put a lander and rover on Mare Imbrium on the lunar near side of the moon in December 2013 – making it only the third country to soft-land on the moon – the Chang’e 4, originally designed to be a backup for Chang’e 3 was repurposed for a more demanding mission.
Actually, the lander and rover are very similar in appearance to the Chang’e 3, but the Chang’e 4 has been adapted to meet the new mission requirements. Hardware and instruments onboard will allow for a study of some of the moon’s most ancient rocks — which could help scientists understand the moon’s extremely violent history.
The rover will also carry a Panoramic Camera (PCAM) and Lunar Penetrating Radar (LPR). Additionally, a Visible and Near-Infrared Imaging Spectrometer (VNIS) and Advanced Small Analyzer for Neutrals (ASAN) will be onboard. The VNIS and ASAN were developed by the Swedish Institute of Space Physics, Kiruna.
The mission will also be scouting for a location to build an unprecedented telescope to study the Big Bang’s afterglow, according to Air and Space magazine. The lunar lander will more than likely deploy a demonstration experiment to observe the low-frequency radio sky from the far side, a region of the moon that never faces the Earth due to tidal locking.
To facilitate the communication experiment, China launched Queqiao, a satellite with a 4.2-meter parabolic antenna on May 20 from Xichang. The satellite entered a Lissajous orbit June 14 beyond the moon around the Earth-moon Lagrange point 2. This orbit will allow Queqiao to be in a constant line-of-sight with both the lunar far side and terrestrial tracking stations.
Queqiao will relay telecommands from the ground to the Chang’e 4 lunar spacecraft and transmit data and telemetry back to Earth via S-band while using X-band to communicate with the lander and rover.
