China's Mars sample-return mission may include helicopter and robot

China's upcoming Mars sample return mission, the Tianwen-3, is expected to launch sometime around 2030, according to a presentation by Liu Jizhong, director of China's Lunar Exploration and Space Program Centre, and Hou Zengqian from the Chinese Academy of Geological Sciences. 

The presentation, which was made at the International Conference of Deep Space Sciences in Hefei, Anhui province on April 22, outlines the mission's science objectives, including sample collection and mobile sampling.

The Tianwen-3 mission will involve a dual launch of two Long March 5 rockets, each carrying a vehicle stack. One stack will include a landing vehicle and a two-stage ascent vehicle, while the other will include an orbiter and return craft. 

The landing vehicle will touch down on the Martian surface, collect and store up to 500 grams of material, and then launch back into space. The orbiter will await rendezvous and sample transfer, along with the return vehicle that will store the sample for return to Earth.

The launch vehicle, which will weigh about 790 pounds (360 kilograms), consists of a solid-rocket first stage and a liquid-propellant upper stage, which will rendezvous and dock with its orbital companion using the assistance of the orbiter's robotic arm. 

Samples will then be transferred to the orbiter's return vehicle in preparation for Mars orbital departure and the return journey to Earth.

The mission's surface sample may be collected using a drill and robotic arm to collect soils from as deep as 6 feet (2 meters) below the Martian surface. Mobile sampling is also listed as a mission objective, with criteria outlined for possible landing sites, including evidence of past liquid water, elevation, terrain, geological diversity, and latitudinal positioning optimal for the return to Martian orbit with the sample.

The presentation also contained references to a small helicopter-like drone and a six-legged robot, although it is not clear from the slides which will be responsible for sample collection. The Tianwen-3 mission is expected to beat the schedule currently set for a similar Mars sample return mission being planned by NASA and the European Space Agency (ESA), which is shooting for a 2033 sample return date. However, the recent presentation did not provide an expected launch date, which may indicate a delay in China's expectations for the mission.