China's 1st Mars rover steps out to explore red planet

The six-wheeled solar-powered rover named Zhurong, resembling a blue butterfly and with a mass of 240 kg, slowly trundled off a ramp on the lander to hit the red, sandy soil of Mars, starting its journey to explore the fourth planet from the Sun, the China National Space Administration (CNSA) said.

China''s Tianwen-1 mission, consisting of an orbiter, a lander and a rover, was launched on July 23, 2020.

The lander carrying the rover touched down in the southern part of Utopia Planitia, a vast plain on the northern hemisphere of Mars, on May 15.

Chinese spacecraft landed on Mars three months after the successful landing of the US space agency NASA''s Perseverance rover which is busy exploring the red planet''s surface with a helicopter hovering around.

With an expected lifespan of at least 90 Martian days (about three months on the Earth), Zhurong will record the Martian landscape with high-resolution three-dimensional images, analyse the material composition of the planet''s surface, detect its subsurface structure and magnetic field, search for traces of water, ice and observe the surrounding meteorological environment, state-run Xinhua news agency reported.

It carries various scientific instruments, including terrain camera, multi-spectral camera, subsurface exploration radar, surface-composition detector, magnetic-field detector and meteorology monitor.

The orbiter, with a design life of one Martian year (about 687 days on the Earth), will relay communications for the rover while conducting its own scientific detection operations.

Compared with China''s lunar rover Yutu (Jade Rabbit), Zhurong has a similar speed of about 200 meters per hour, but the height of the obstacles it can surmount increased from 20 cm to 30 cm. It can climb slopes up to 20 degrees.

Zhurong''s six wheels are independently driven, according to its designers.

The US has deployed five rovers on Mars, besides a helicopter.

The active suspension system of the rover could help it to get out of trouble by moving like an inchworm on the complicated Martian surface with both loose sandy soil and densely distributed rocks, said Jia Yang, deputy chief designer of the Tianwen-1 probe from the China Academy of Space Technology.

Zhurong can also walk sideways like a crab. Each of its six wheels can turn in any direction, which could be used for avoiding obstacles and climbing slopes.

Mars is farther away from the Sun than the Earth and the moon, and the Martian atmosphere also reduces sunlight, so the solar panels of the Mars rover are about twice that of the lunar rover.

They need to be rotatable to follow the Sun, said Geng Yan, an official at the Lunar Exploration and Space Program Center of the CNSA.

Zhurong''s solar panels were specially designed to adapt to the sunlight on Mars, which has a spectrum different from that on the Earth''s orbit, Geng said.

Mars is notorious for its sand storms, and the dust could reduce the efficiency of power generation. The specially processed solar panels make it difficult for dust to accumulate, just like the water drops on the lotus leaf, which can be blown away by the wind, Geng said, adding that the robotic Zhurong will operate with a cycle in the order of environmental perception, scientific exploration and movement.

The one-way communication time delay of about 20 minutes between the Earth and Mars due to the long distance between the two planets requires the Mars rover to operate and deal with complex problems autonomously since ground control may not be timely.

In the case of a sandstorm, Zhurong can decide when to cancel its work and "go to sleep" autonomously and wake up when sunlight is sufficient again.

"When designing the Mars rover, we had many rounds of brainstorms to create a powerful and pretty rover that could represent the best level of Chinese space engineers," Jia added.

China''s space programme has suffered relatively few setbacks since it first put an astronaut into orbit in 2003, although the space station launch was delayed by the failure of an earlier version of the massive Long March 5B rocket.

China earlier launched two smaller experimental space stations.

It has been excluded from the International Space Station largely at the insistence of the US, which is wary of the secrecy surrounding the Chinese space programme and its close links to the military.

Congressional approval is also required for any cooperation between NASA and the CNSA.