Zhurong (Rover)

1. Historical Background and Detailed Objectives

Zhurong represented CNSA's first Martian rover and the main mobile component of the ambitious composite Tianwen-1 mission. The scientific gap it aimed to fill encompassed the geological and atmospheric study of the Martian northern plains. Primary objectives focused on investigating the surface geology and internal structure of the planet using radar, searching for evidence of subsurface water or water ice, analyzing the mineralogical and geochemical composition of the soil, and studying meteorological and climatic characteristics as well as the local magnetic field.

2. Vehicle Architecture and Main Subsystems

The Zhurong rover has a launch mass of 240 kg. Its approximate dimensions with solar panels deployed are 2.6 m in length, 3.0 m in width, and 1.85 m in height. The power system relies on deployable solar panels made of an ultra-thin film and anti-dust coatings that generate an estimated power of about 140 W (analogy: an autonomous miniature generation network optimized for arid and low-insolation environments). Communications are carried out via a UHF band relay link through the Tianwen-1 orbiter, which forwards the data back to Earth. Its mobility is supported by a six-wheeled chassis with a rocker-bogie suspension system.

3. Payload and Scientific Instrumentation

The embarked scientific instrument suite included:

• MarSCoDe (Mars Surface Composition Detector): Surface composition detector using laser-induced breakdown spectroscopy (LIBS).
• MCS (Mars Climate Station / MetCC): Meteorological station to record pressure, temperature, wind speed and direction, as well as ambient sound.
• MSCam (Mars Surface Camera): Multispectral camera for lithological and topographic analysis of the environment.
• NaTeCam (Navigation and Terrain Camera): Navigation and terrain cameras for geomorphological mapping and trajectory planning.
• RoMAG (Mars Rover Magnetometer): Magnetometer for studying the local magnetic field of the Martian crust.
• RoPeR (Mars Rover Penetrating Radar): Deep subsurface radar (at low and high frequencies) to image the stratigraphic structure and search for subsurface water or ice.

4. Chronology and Mission Phases

Following the launch on July 23, 2020 via a Long March 5 carrier rocket from Wenchang, the probe completed orbital insertion on February 10, 2021. Landing in Utopia Planitia occurred on May 14, 2021 (recorded locally in China on May 15), followed by surface deployment on May 22, 2021. After successfully exceeding its nominal 90-sol design in August 2021, the mission entered its extended mission phase, accumulating a distance of 1,921 meters over more than 347 sols of operational activity before scheduled hibernation on May 18, 2022.

5. Results and Discoveries

The RoPeR radar revealed a complex subsurface stratigraphy up to 80 meters deep in Utopia Planitia, highlighting the presence of two main sedimentary layers formed by aqueous activity between 3.2 billion and 3.5 billion years ago. Likewise, the analyses provided evidence of recent geological processes during the mid-to-late Amazonian period linked to the prolonged presence of surface or shallow liquid water in the form of lacustrine or shallow marine environments.

6. Legacy and Significance

Although the rover entered hibernation on May 18, 2022 to protect itself from the Martian winter and never resumed communications due to excessive and irreversible dust accumulation on its solar panels in late 2022, Zhurong consolidated China's technological and scientific success in the in situ planetary exploration of Mars.