Apollo 15 image captures landing locale of China’s Chang’e-5 Moon lander – the Mons Rümker region in the northern part of Oceanus Procellarum.
Credit: NASA

China’s bid to return to Earth samples from the Moon since the 1970s is slated for next year.

The 2019 liftoff of the highly complex mission of Chang’e-5 on a Long March 5 booster is targeted for the Moon’s Rümker region in Northern Oceanus Procellarum. Mons Rümker is seen as the most distinctive geological feature in the area, characterized by prolonged lunar volcanism forming multiple geologic units in the area.

Location of the Rümker region and previous landing sites. The Rümker region is located in northern Oceanus
Procellarum, away from previous sampling sites. The basemap is a Lunar Orbiter Laser Altimeter and Kaguya Terrain
Camera merged hillshade map (simple cylindrical projection).
Credit: Barker, et al., 2016

Four-part spacecraft

According to Chinese news services, Chang’e-5 is comprised of four parts: the orbiter, lander, ascender, and Earth reentry module.

The lander and ascender form a combination that will touch down on the Moon to conduct robotic lunar sampling duties. The specimens will then be rocketed into lunar orbit, followed by an auto-pilot docking and transfer of those collectibles into the mission’s Earth reentry module.

Large volcanic complexes

The significance of the Chang’e-5 return sample mission has been detailed in a new research paper, led by Yuqi Qian of the State Key Laboratory of Geological Processes and Mineral Resources, Planetary Science Institute, School of Earth Sciences at China University of Geosciences in Wuhan, China.

Chang’e-5 mission rocket’s lunar samples into Moon orbit.
Credit: CCTV/Screengrab

“Recent studies find that the geological features and volcanic history of the Moon are far more complex than previously thought,” the paper explains, “and many of the most interesting areas have been neither explored nor sampled.” One such area is the northern Oceanus Procellarum region which consists of very young mare materials and hosts one of the largest volcanic complexes on the Moon, Mons Rümker. The steep-sided domes and shallow domes on Mons Rümker were likely formed at different stages of evolution of this volcanic complex.

The location of proposed Chang’e-5 landing sites. Landing site A indicates the region of the Em4 mare unit, considered both the science-richest unit and also an area that’s suitable for landing.
Credit: Qian, et al.

Detailed mapping

The landing region for China’s Chang’E-5 lunar sample return mission has undergone detailed geological mapping using image, spectral, and altimetry data. Fourteen geological units were defined, a geologic map was constructed, and the geologic history has been outlined. To maximize the scientific value of the returned samples, lunar researchers assessed the scientific importance of each unit, suggesting that the young mare basalt unit is the most valuable for sample return and is a top priority.

Laboratory studies

A little over 4 pounds (2 kilograms) of lunar samples from the surface and subsurface — up to 6.5 feet (2 meters) in depth — are planned to be collected and returned to the Earth. Accomplishing that feat provides an opportunity to study new lunar samples in terrestrial laboratories since the former Soviet Union’s Luna-24 samples mission in 1976.

Laboratory studies of lunar samples from Apollo and Luna missions solved numerous fundamental scientific issues of selenology and heralded the beginning of a golden age of lunar research that continues to this day, the research paper explains. “However, most of the Moon remains unexplored and there are still many unanswered scientific questions that remain to be addressed by returned samples.”

China’s Chang’e-5 lunar sample return mission to the Rümker region provides a great opportunity to solve some of the significant outstanding questions of lunar science. Samples from each geologic unit in the area have specific scientific importance, which should be ranked to maximize the science outcomes.

Terrane camera (TC) morning map of the Rümker region (Lambert conformal conic projection). The white
box denotes the Chang’e-5 landing region. The yellow boxes represent other locations noted in the research paper. The yellow
dashed lines denote the ejecta from Harpalus carter. The blue dashed lines denote ejecta from Pythagoras crater. The
green dashed lines denote ejecta probably from Copernicus crater. Credit: Qian, et al.

Science-rich and safe site

The proposed landing site A (Em4) “is not only the very highest scientific priority but also very favorable from an engineering and landing safety point of view,” the research paper points out. “It offers a relatively safe landing site, which is regionally flat, young, and is really homogeneous and so does not require pin-point landing.” The research paper observes that Em4 is both the science-richest unit and also an area that’s suitable for landing.

To date, no samples have been returned from such young lunar units, and, thus, there is a high level of uncertainty in the size-frequency distribution ages in the last half of lunar impact chronology

If successful, Chang’e-5’s return of samples from these young basalts would provide an absolute calibration for the cratering flux, an accomplishment that will assist in understanding the geological evolution of planetary bodies throughout the Solar System.

To read the paper – “Geology and Scientific Significance of the Rümker Region in Northern Oceanus Procellarum: China’s Chang’E-5 Landing Region” — go to the American Geophysical Union’s Journal of Geophysical Research: Planets at:

https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2018JE005595

One Response to “China’s Bold Moon-to-Earth Sampling Mission: Site Selection and Scientific Return Spotlighted”

  • Phil Clark says:

    The Chinese have confirmed that the over-complex Chang’E 5 mission profile is a “dummy run” for a Mars sample-return mission, planned for an early flight of the CZ-9 launcher in around ten years time.

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