New details of the Tianwen-3 mission to collect samples from Mars and return them to Earth were revealed in presentations made at the Hefei International Conference in Anhui province on April 22. The mission will use a pair of Long March-5 rockets to send two separate spacecraft to the Red Planet around 2030 to collect and return 500 grams of samples.
The Chinese program for the exploration of Mars
After the unfortunate Yinghuo-1 mission, launched on Nov. 8, 2011, together with the Russian probe Phobos-Grunt, which was lost together with it, the Chinese program for the exploration of Mars scored a resounding success with the Tianwen-1 mission, launched on Jul. 23, 2020, and arrived on the red planet on February 10, 2021.
The name Tianwen means “search for celestial truth” and the missions to Mars are aimed at finding answers to the questions that the planet has always put before us. The first probe of the series, consisting of an orbiter and a lander, Zhurong, (a mythological Chinese god of fire) has successfully carried out all the assigned tasks and is currently on standby, probably with damaged solar panels, in the Martian region of Utopia Planitia, not far from the Viking-2 landing site.
A different approach
The next step in the Chinese conquest of Mars will be to launch two separate probes, one equipped with a lander which will have to collect Martian soil samples and send them into orbit utilizing an ascent device that will join up with the second probe which, once docked the vehicle with the pieces, it will return to Earth, delivering the precious cargo.
Unlike the mission profile studied by ESA and NASA for the Sample return mission, which envisages the launch of a single vehicle separated into a lander and an orbiter, the Chinese project uses two Long March-5 launches which will depart from Wenchang in November 2028.
The return of the samples to our planet would take place in Jul. 2031, two years before the return of the samples collected by the Euro-US probe.
China’s Tianwen-3 mission will likely only collect samples from a single location, while the joint NASA and ESA mission will collect samples to Mars from multiple locations.
Flying drone or four-legged crawling robot?
Experience gained with the Tianwen-1 mission has already shown that China possesses the technology needed to land in the flat and low-lying region of Utopia Planitia in the northern hemisphere, thus giving the spacecraft more time in the atmosphere to slow down its descent. Landing at higher altitudes on Mars, as some NASA spacecraft have done, would require further refinements of entry, descent, and landing technology and increase mission complexity.
For the collection of materials to be sent, we thought of a mini helicopter, very similar to Ingenuity. Alternatively, a four-legged crawling robot design has been presented that could be used to sample sites further away from the lander.