By 
November 28th, 2024
Image credit: CCTV/Inside Outer Space
Returning Mars samples is on China’s agenda, returning them to Earth around 2031.
According to a newly published research paper, the Tianwen-3 spacecraft involves two launches around 2028, retrieving Red Planet specimens for lab looks here on Earth around 2031.
According to the paper appearing in the National Science Review journal – “The search for life signatures on Mars by the Tianwen-3 (TW-3) Mars sample return mission” – where on Mars to sample, what to choose, how to sample and how to utilize the collected materials are being appraised.
At China’s Deep Space Exploration Laboratory, the mission’s chief scientist Hou Zengqian and its chief designer Liu Jizhong, with colleagues, are blueprinting their exploration strategy. “The primary scientific goal of which is to search for signatures of life on Mars,” they explain.
China blueprint for Mars sample return mission.
Image credit: Kanyan Xu/COSPAR
Under review
Where to sample: Currently, the TW-3 science group proposes 86 potential landing sites, primarily concentrated in the Chryse Planitia region and Utopia Planitia region. These sites encompass diverse geological environments, such as ancient coastlines, deltas, ancient lakes, and canyon systems, providing favorable conditions for the origin and preservation of ancient life.
What to choose: How best to identify, where to find, and how to preserve biosignatures, and systematically establishing identification methods to differentiate potential biosignatures, false positives, and false negatives.
How to sample: Define the depth and grain size requirements for Mars sample collection. For the returned samples, there will be noticeable differences in the types and characteristics of the samples required for mineralogical and biomaterial analysis. Sampling sites including surface sample collection and drilling.
How to utilize: The returned sample should be stored following a planetary protection strategy before laboratory analysis. Currently, the biosignatures used in the detection of extraterrestrial life mainly include living organisms, fossils, substances derived from life processes, and chemical signals.
China’s Zhurong rover explored Utopia Planitia region.
Credit: CNSA
Safe landing spots
Hou and Liu report in their paper that a criterion has been established which supports the selection of landing sites that are both safe for engineering constraints and of high scientific merit.
The engineering constraints on the TW-3 landing site must take into account altitudes ≤ – 3 km, latitudes ranging from 17° to 30°N, slopes ≤8°, and rock abundances ≤10%.
“Other engineering constraints, such as dust storm conditions, illumination, and temperature also need to be considered further,” the researchers explain.
Integrated work
To hone China’s Mars sampling effort, integrated work is underway that includes remote sensing, comparative studies with Mars-like environments, laboratory simulations of Martian conditions, meteorites, and simulated samples.
Credit: CCTV/Inside Outer Space screengrab
Also, detailed research has been conducted on the types of potential biosignatures, reservoirs, sample collection strategies, and detection and analysis methods, Hou and Liu explain.
“This study will effectively support the TW-3 mission in achieving significant discoveries in the exploration of biosignatures on Mars, and contribute to the establishment of a scientific theoretical framework for the origin and evolution of life,” the research paper concludes.
Go to the detailed research paper – “The search for life signatures on Mars by the Tianwen-3 Mars sample return mission” – in National Science Review, Volume 11, Issue 11, November 2024 at:
Posted in Space News
