China Plans to Return Samples from Mars by 2030, and Possible Landing Sites have been Identified
China has trimmed down possible landing sites for its Tianwen-3 Mars sample return mission and is moving closer to launching the mission in 2030.
According to Sun Zezhou, senior engineer at the China Academy of Space Technology (CAST), work on China’s Tianwen-3 Mars sample return mission is moving “relatively smoothly” and is scheduled to launch in 2030 or so, China Central Television (CCTV) reported on March 6. China’s successful Tianwen-1 Mars orbiter and rover mission was chiefly designed by Sun.
Though brief and ambiguous, the update coincides with NASA’s reevaluation of the Mars Sample Return (MSR) mission in light of significant scheduling and financial challenges. The decision of MSR spending was postponed by a final fiscal year 2024 spending bill.
Though it takes a less complicated method than NASA’s, China’s Tianwen-3 Mars sample return architecture is nevertheless an extremely complicated mission. A lander, an ascent vehicle, and an orbiter and return module will be launched in two separate Long March 5 missions. The technologies employed for the Tianwen-1 rover landing will be improved upon throughout entry, descent, and landing.
The lander will gather material from up to two meters below the surface using a drill and gather surface samples using a robotic arm. To increase the ability to gather a wider variety of samples, the mission might also include the use of a six-legged crawling robot or a helicopter similar to Ingenuity. The mission’s goal is to bring 500 grams or so of Martian samples back to Earth.
The primary difficulties, according to Sun, are gathering rock samples, flying off from Mars’ surface, meeting and docking in orbit, and then moving the rocks to a reentry module. They necessitate a high level of system design autonomy.
According to Sun, the technological framework is already in place. China has experience in Mars entry, descent, and landing thanks to Tianwen-1. Additionally, it has launched and sampled from a different planetary body as part of the Chang’e-5 lunar sample return mission. Sun went on to say that the materials might contribute to the investigation into the possibility of past signs of life on Mars.
Speaking outside of China’s ongoing annual legislature sessions in Beijing, Sun was a speaker. His remarks offer scant information on how the mission is progressing. Chinese officials had previously announced a 2028 launch date and a 2031 return date for samples. The mission will not launch into the Mars launch window, according to the 2030 announcement. This implies that there will be a 26-month wait for the next chance.
Choosing the Landing Site for Tianwen-3
Three preselected landing zones for Tianwen-3 are also revealed in a recent study report published in the journal JGR Planets. These are the regions known as Chryse Planitia, Utopia Planitia (where the Zhurong Tianwen-1 rover landed), and Amazonis Planitia.
The flow of air, dust, or water in a circle—known as Martian atmospheric eddies—is evaluated in this research. It suggests avoiding areas where air eddies occur frequently in order to ensure the safety of the Tianwen-3 landing and ascent phases. According to the paper, Chryse Planitia would be the best place for Tianwen-3 to land.
The lowland plain of Chryse Planitia served as the Zhurong rover’s alternate landing site. Located at the easternmost point of the extensive outflow canal system called Valles Marineris is the circular plain. It is of astrobiological importance because it may contain proof of water once flowing on Mars. Additionally, the Viking 1 lander descended onto Chryse Planitia.
Because of the need for electricity and illumination, the three sites are located between 17 and 30 degrees north latitude. Becoming at least 2,000 meters, or ideally 3,000 meters, below the average global Martian elevation is one of the other restrictions. In order to slow down its entry into the Martian surface, this gives the lander more atmosphere to travel through. The final site will probably be chosen with feedback from the new paper, not by it.
Presentations at an International Conference of Deep Space Sciences in Hefei, China, in April 2023, indicated that potential landing ellipses of 50 by 20 kilometers had been located within these locations.
The presentations state that science aims will also be taken into consideration while choosing a site. Prioritizing Martian topography older than 3.5 billion years, the selected place must be deemed of astrobiological significance.
Additional top goals include geological diversity, traces of ancient aquatic activity, and habitats like sedimentary or hydrothermal systems that are conducive to the formation and preservation of life.
One of the main priorities suggested by the Planetary Science Decadal Surveys is to return samples from Mars. According to the paper, MSR is critical to NASA, American leadership in planetary science, and global collaboration from a strategic and tactical standpoint.
A mission’s success would mark a significant engineering achievement and yield important scientific findings. Samples could improve comparative planetology and offer novel insights into the planet’s geological history and processes. Above all, it might perhaps give biosignatures, or chemical signs of previous or even current life. China may try to obtain Martian samples and conduct ground-breaking research first due to the ambiguity surrounding the MSR.
