Monday, May 29, 2017

China's planned far side of Moon sample mission




A view of the far side of the Moon and the distant Earth, captured by the 2014 Change 5-T1 mission.

China is progressing with plans to launch an unprecedented attempt to collect samples from the far side of the Moon in 2020, as well as future polar missions, following a meeting of top lunar scientists and space officials in Beijing.

The ambitious and complex Chang'e-6 mission is part of wider plans outlined for the exploration of the Moon which will follow on from the original three-stage Chinese Lunar Exploration Project (中国探月工程).

Chang'e-6 would follow the first ever landing on the far side of the Moon by the Chang'e-4 lander and rover mission, scheduled for late 2018, and would likely also target the scientifically significant South Pole-Aitken Basin.

Probes to both lunar poles are also being developed for the decade of 2020, which tentatively involve surface exploration, resource development and related technology validation.

"The exploration of lunar poles is a significant innovation in human history, which has drawn great attention from around the world. It will also lay a solid foundation for deeper and more accurate Moon probes in the future," Tian Yulong, chief engineer at SASTIND, said in October.

Such missions will also be of interest to the European Space Agency (ESA), which has been discussing cooperation in and coordination of lunar exploration plans with China as part of ESA's 'Moon Village' concept.

In March, Mr Wu told Xinhua agency that Chang'e-6 would target a 2020 launch, but that the mission had not yet been officially approved.

Such a declaration could only realistically come after success of China's first, near-side lunar sample return mission, Chang'e-5, which will launch on a Long March 5 heavy lift rocket from Wenchang in November.

CLEP has so far involved two orbiters, Chang'e-1 and 2, and a lander and rover mission, Chang'e-3 in 2013, and will culminate in the Chang'e-5 lunar sample return mission.

The four-part probe involves orbiting, landing, collecting samples, ascending to lunar orbit, rendezvous and docking in orbit, high-speed return to Earth and a skip reentry into the atmosphere.

The mission, the first of its kind since Soviet's Luna 24 in 1976, could return by far the youngest samples of lunar material so far, and will also prove useful experience for human landings in the future.

If the complex Chang'e-5 mission succeeds in bringing 2 kg of lunar samples back to Earth, Chang'e-6 - the designated backup spacecraft - will then be tasked with the scientific and exploration first of retrieving material from the far side of the Moon.

The far side of the Moon is not visible to Earth due to 'tidal locking', meaning tracking and communicating with the probe directly is not possible.

Thus facilitating a landing on the lunar far side will be a communications relay satellite, stationed in a halo orbit around the second Earth-Moon Lagrange Point beyond the Moon.

This will be launched around six months before the launch of Chang'e-4, which itself is a re-purposed backup to the successful Chang'e-3 mission which involved the Yutu, or Jade Rabbit, rover.


SASTIND, which oversees the Chinese space programme, last autumn stated that it is developing a 20 year strategy for lunar and interplanetary exploration, including the above plans, missions to Mars and potential human landings on the Moon.

While such a goal has been often stated in the media, there is mounting evidence that China is working on the capabilities required for putting astronauts on the lunar surface and getting them home.

In June 2016 as part of the debut flight of the Long March 7 rocket, a scale version of a return capsule for crewed deep space missions was successfully tested.

China is working on two variants of a successor to the crewed Shenzhou spacecraft, with masses of 14 and 20 metric tonnes and capable of accommodating 4-6 astronauts.

And early research into a launch vehicle powerful enough to send the required mass toward to Moon, the Saturn V-class (and Russian failed N1 class) Long March 9 rocket, is already underway.

Long March 9. Long March 9 (LM-9, CZ-9, or Changzheng 9, Chinese: 长征九号) is a Chinese super-heavy carrier rocket that is currently in study. It is planned for a maximum payload capacity of at least 140,000 kg to LEO or at least 50,000 kg to Lunar Transfer Orbit.