HELSINKI – China is finalizing the plans for its Tianwen-3 expedition to retrieve samples from Mars and transport them back to Earth.
During presentations at the International Conference of Deep Space Sciences in Hefei, Anhui province, on April 22, new mission specifics and defined goals were disclosed.
The mission is set to utilize a pair of Long March 5 rockets to dispatch two distinct sets of spacecraft towards the Red Planet by around 2030, with the objective of gathering and bringing back 500 grams of samples.
The mission aims to explore possible signs of life on Mars, comprehend the environmental changes and climate evolution of the Red Planet, and examine its potential habitability in the past.
The two launches of the Long March 5 rockets will include a landing and ascent vehicle, as well as an orbiter and a return module, respectively. The technology for entry, descent, and landing will be built upon the methods used during the Zhurong rover landing as part of China’s Tianwen-1 Mars mission.
Just like China’s 2020 Chang’e-5 Lunar sample return missions, the sample collection process will involve using a robotic arm on the lander to gather surface samples and a drill to extract materials from depths of up to two meters beneath the surface.
In a new development, the landing segment will also incorporate a limited capacity for collecting samples in the vicinity of the landing site, employing either a six-legged crawler robot or a helicopter similar to Ingenuity. The Chinese Academy of Sciences (CAS) showcased a model of the latter in 2021.
Once collected, the samples will be transferred to Mars orbit with a two-stage ascent vehicle. This vehicle will consist of a solid first stage and a liquid propellant upper stage, with a total weight of no less than 360 kg.
Subsequently, the ascent vehicle will rendezvous with the orbiter and return module, with the docking process assisted by a robotic arm. The collected samples will then be moved to the return module for the journey back to Earth.
While the precise launch timeline remains uncertain, it indicates a potential delay from the previously announced 2028 launch schedule.
A mission summary for China’s Mars sample return, presented in June 2022, aimed for launch in late 2028 with sample delivery on Earth in July 2031.
The proposed 2028 timeline would see the samples returned to Earth prior to NASA-ESA Mars Sample Return mission. Additionally, the mission is designed to transport roughly 500 grams of Mars samples back to Earth.
The selection of the landing site involves input from international teams, with technical constraints necessitating a landing between 17 and 30 degrees north latitude to meet energy and illumination requirements. The designated landing area will measure 50 by 20 kilometers.
The chosen sites must have an elevation of at least 3,000 meters below zero, equivalent to sea level on Earth. This altitude provides the lander with added atmosphere to enable a gradual descent to the Martian surface.
The selection of sites will be based on scientific criteria, prioritizing locations with astrobiological significance and terrains on Mars older than 3.5 billion years.
Environments conducive to the emergence and preservation of life, such as sedimentary or hydrothermal systems, signs of past water activity, and geological diversity, are highlighted as primary considerations.
The mission will follow strict planetary protection measures, as mentioned in the presentations.
Liu Jizhong from the director of China’s Lunar Exploration and Space Program Center at CNSA, and Hou Zengqian from the Institute of Geology, Chinese Academy of Geological Sciences, delivered presentations in Hefei, which were later circulated on Chinese social media.
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