Leonard David's INSIDE OUTER SPACE

Image credit: Zengqian Hou, et al.

China’s aim to haul back to Earth bits and pieces of Mars via its Tianwen-3 mission is underscored in a new research paper, an effort to collect and rocket back at least a pound (500 grams) of the extraterrestrial goodies around 2031.

The preliminary proposed payload for the lander has been completed, as have preliminary studies on a strategy for the selection of the landing site.

Also detailed is development of a forward and back-contamination strategy, including the establishment of a dedicated laboratory for the preservation and analysis of the returned Martian samples.

Schematic overview of China’s MSR mission. The lander configuration with
drilling and scooping payloads for biosignature analysis is shown on the left. The uncrewed drone, deployed for rock sampling at remote locations (operational
range is greater than 300 feet (over 100 meters), is shown on the right. All samples ascend to the orbiter.
The layered structure in the lower right highlights potential compositional
stratification within the Martian regolith (schematic representation, not to scale).
Image credit: Zengqian Hou, et al.

Landing sites

China’s landing zone stems from a review of 86 preliminary landing sites. The final, chosen site will favor the emergence and preservation of evidence of traces of life and detection of potential biosignatures in the returned samples.

“The mission aims to provide insights into nine scientific themes centered around the main focus of the search for extant and past life on Mars,” lead author Zengqian Hou of the Institute of Deep Space Sciences, Deep Space Exploration Laboratory, in Hefei, China.

Zengqian and colleagues presented their perspectives on China’s Mars Sample Return (MSR) in Nature Astronomy.

Where to collect, what to collect, how to collect, how to analyze

“Collecting samples from Mars could provide accurate data on the signs of life,” the research team explains.

The scientists detail the issues of where to collect, what to collect, how to collect, and how to analyze.

The plan is to launch two boosters in 2028 in support of MSR, and haul samples back from Mars in 2031. A drill mounted on the lander will penetrate to a depth of 6.5 feet (2 meters) to collect several grams of subsurface samples, while a robotic arm will gather more than 400 grams of surface material from the landing site.

According to artwork in the paper, also to be utilized is an arm-mounted helicopter. This drone is to be deployed for rock sampling at locations greater than 300 feet (over 100 meters) from the lander.

Image credit: Zengqian Hou, et al.

Lander payload

The preliminary proposed payload for the MSR lander includes a Mars Subsurface Penetrating Radar and a Raman and Fluorescence Analyzer for Mars.

The Mars Subsurface Penetrating Radar would gather data on the structure of the shallow subsurface in the study area, as well as help in the selection of drilling sites and monitor drilling operations.

The Raman and Fluorescence analyzer for Mars combines Raman and fluorescence spectroscopy with microscopic multispectral detection, enabling microscopic, on-the-spot measurements of materials on the Martian surface. It can resolve the composition of silicates, oxides, organic compounds and hydrated minerals, and thus help with sample selection.

Planetary protection

China’s MSR mission requires “stringent measures” to prevent potentially living life (presumably microorganisms) from being contaminated by Earth’s biosphere (Forward Planetary Protection) and, “more importantly, to protect Earth from an invasion of Martian life (Backward Planetary Protection),” write Zengqian and colleagues.

Image credit: CCTV/Inside Outer Space

“Although we expect the samples returned from Mars to contain only evidence of the expected life that once existed on Mars billions of years ago, we will still set up a laboratory to quarantine the suspected Martian life and ensure the highest level of biosafety,” the research paper explains.

Dedicated laboratory

It is essential, the research team adds, to set up a dedicated laboratory for the preservation and analysis of the returned Martian samples. This laboratory must maintain high standards of cleanliness with the highest level of biocontainment and analytical capabilities, they explain.

At present, no such laboratory anywhere in the world exists that is specifically designed to handle and analyze samples from Mars, where life is suspected, Zengqian and colleagues observe.

“Once biohazard testing confirms that the returned Mars samples pose no risk to Earth’s biosphere, the Biosafety Protection Zone can be converted to a higher-grade cleanroom laboratory to reduce overall operating costs,” the MSR specialists write.

The Red Planet as seen by Europe’s Mars Express.
Image credit: ESA/D. O’Donnell – CC BY-SA IGO

Win-win cooperation

Zengqian and colleagues conclude in the paper that the exploration of Mars is a collective endeavor for all of humanity.

“The Tianwen-3 mission is committed to win–win cooperation, harmonious coexistence and shared prosperity through international cooperation. It actively seeks international partnerships through various channels and at various levels for joint scientific research, landing site selection and scientific payload development and testing.”

To gain access to the Nature Astronomy paper – “In search of signs of life on Mars with China’s sample return mission Tianwen-3” – go to: https://doi.org/10.1038/s41550-025-02572-0