Leonard David's INSIDE OUTER SPACE

China’s Chang’e-5 robotic sample return mission.
Credit: CNSA/CLEP

A glimpse into China’s readiness to handle samples from the Moon reveals steps to be taken for storage, processing and preparation of the specimens.

China’s Chang’e-5 robotic lunar sample return mission is slated for liftoff later this year. That venture represents the third phase of China’s lunar exploration project -returning samples from the Moon.

The reported candidate landing region for China’s Chang’e‐5 lunar sample return mission is the Rümker region, located in the northern Oceanus Procellarum. The area is geologically complex and known for its volcanic activity.

The white box denotes the Chang’e-5 landing region. The yellow boxes represent other locations noted in a recent 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.

The Chang’e-5 mission will retrieve and return to Earth up to 4.4 pounds (2 kilograms) of lunar surface and subsurface samples.

The aggressive Chang’e-5 mission is comprised of four parts including the orbiter, ascender, lander, and Earth reentry module containing the lunar specimens.

Moonwalking geologist, Apollo 17’s Jack Schmitt.
Credit: NASA

Sample history

The former Soviet Union successfully executed three robotic sample return missions: Luna 16 returned a small sample (101 grams) from Mare Fecunditatis in September of 1970; February 1972, Luna 20 returned 55 grams of soil from the Apollonius highlands region; Luna 24 retrieved 170.1 grams of lunar samples from the Moon’s Mare Crisium (Sea of Crisis) for return to Earth in August 1976.

The last Apollo mission to bring back to Earth lunar collectibles was the Apollo 17 expedition in 1972. During 1969-1972, the six Apollo missions collected 842 pounds (382 kilograms) of lunar samples at different landing sites on the lunar surface, including rocks, core samples, lunar soil and dust.

Credit: G. L. Zhang, et al.

China’s plans

In a paper to be presented at this month’s now-cancelled Lunar and Planetary Science Conference (LPSC) due to concerns about the COVID-19 virus, lead author, G. L. Zhang from the National Astronomical Observatory, Chinese Academy of Sciences, details the main tasks of the Ground Research Application System (GRAS) of the country’s lunar exploration project.

They include: receiving lunar samples from the spacecraft system; establishing special facilities and laboratories for sample permanent local storage and backup storage at another location; and preparation and preprocessing of lunar samples.

According to the requirements of the mission, GRAS formed a complete lunar sample preprocessing, storage and preparation plan.

This plan mainly includes: handover and transfer of lunar samples from spacecraft system to GRAS, unsealing of the sample package, sample separation (drilled sample separation and scooped sample separation), sample storage (scooped and drilled samples) and sample preparation.

Credit: G. L. Zhang, et al.

Pipeline

A detailed pipeline for this plan is discussed in the LPSC paper.

Firstly, the returned lunar samples will be divided into scooped samples and drilled samples after them entering the lab. Secondly, both scooped and drilled samples will be then divided into four categories: permanent storage samples, backup permanent storage samples, scientific research samples and exhibition samples.

“All the tools that contact with lunar sample are made of stainless steel, teflon, quartz glass or materials of known composition to strictly control the factors that will affect subsequent scientific analysis. The water and oxygen content in the glove box, filled with pure [nitrogen], will be strictly monitored to prevent the lunar samples from earth pollution,” the LPSC paper notes.

Lunar Sample Laboratory Facility at Johnson Space Center in Houston, Texas.
Credit: NASA

U.S., China approaches

“They seem to be taking a very similar approach to how we have (and continue to) process and curate Apollo samples (and other astromaterials in our collection),” responds Ryan Zeigler,  NASA’s Apollo Sample Curator and the Manager of the Astromaterials Acquisition and Curation Office of the Astromaterials Research and Exploration Science (ARES) Division at the NASA Johnson Space Center in Houston, Texas.

“There are a few minor differences, but that is to be expected since each mission has unique characteristics,” Zeigler told Inside Outer Space.

The Chinese are clearly taking seriously the handling, storage and preliminary examination of a potential set of new lunar samples. The technology described is in many ways similar to the technology in the NASA Lunar Sample Laboratory, notes Carlton Allen, former NASA Astromaterials Curator (retired). 

“The use of a nitrogen atmosphere for preparation, subdivision and storage has proven both necessary and sufficient over 50 years of lunar curation at NASA,” Allen adds. The glovebox photos show that the nitrogen is maintained at positive pressure with respect to the laboratory atmosphere, which has proven important for contamination control.  The importance of restricting the materials that come into contact with the samples, another important aspect of contamination control, is also recognized. 

Allen points out to Inside Outer Space that the technology described by G. L. Zhang and colleagues “has the potential to make these future lunar samples directly comparable to Apollo and Luna samples, which could significantly increase the value of each sample set.”

Credit: Used with permission – Loren Roberts/The Planetary Society at https://www.planetary.org/