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2021-05-14 11:35:24

Mars is expecting a new resident: a Chinese rover.

After a voyage of seven months and several more spent in orbit, the lander of China’s Tianwen-1 spacecraft is scheduled to touch down on Mars between early Saturday morning and Wednesday, the country’s space agency announced Friday.

The lander carries a robotic rover that will explore the red planet. Its successful deployment would make China the second country, after the U.S., to achieve this feat. The Soviet Union previously landed a rover on Mars but lost contact within minutes.

“This will be a milestone in China’s deep space exploration program,” Ge Jian, an astronomy professor at the Shanghai Astronomical Observatory under the Chinese Academy of Sciences, told Sixth Tone. Tianwen-1 is the country’s first independent mission to Mars, but it was nevertheless designed to include orbiting, landing, and roving on the red planet — all in one go.

China has successfully landed on the moon three times, and has even brought back lunar samples to Earth. But landing on Mars is orders of magnitude more difficult, Xiao Long, a planetary scientist at China University of Geosciences in the central city of Wuhan, told Sixth Tone. “The moon is at our doorstep, but Mars is hundreds of times farther away.”

China’s Tianwen-1 Mars rover. Xinhua

China’s Tianwen-1 Mars rover. Xinhua

This distance — between 54 million and 401 million kilometers, depending on the planets’ positions — makes instant communication between ground control and spacecraft impossible. “All you can rely on is the computer programs you set up beforehand,” Xiao said.

The spacecraft’s landing unit has about seven minutes to descend from the top of Mars’ atmosphere to the planet’s surface, during which it has to reduce its speed from nearly 5 kilometers per second to zero. A Mars landing is often referred to as “the seven minutes of terror” because the process is completely autonomous. China’s Chang’e-4 mission, which was the first to land on the far side of the moon, also partly relied on autonomy.

Tianwen-1’s lander is set to touch down in Utopia Planitia, a massive basin on Mars’ northern hemisphere that was also where NASA’s Viking 2 mission landed in 1976.

This will be a milestone in China’s deep space exploration program.

Xiao, who does not participate in the Tianwen-1 program, said Utopia Planitia is generally flat and low-lying, meaning the region has a relatively denser atmosphere. This will make the speed-reducing parachute that Tianwen-1’s landing unit will deploy during its descent more effective.

The area is also of scientific importance, Xiao added. Satellite observations in recent years suggest that there could potentially be life-sustaining ice or water hidden underground.

Among the six instruments engineers have loaded on the Mars rover — named after the Chinese god of fire, Zhurong — is a radar that can probe up to 100 meters into the Martian crust to look for ice at a much higher resolution than satellites.

Launched around the same time, NASA’s Perseverance rover touched down on Mars in February. Zhurong’s late arrival is partly because of a lack of data on the landing area, according to Xiao. The U.S. has several satellites orbiting Mars from previous missions that had gathered data beforehand, while China’s Tianwen-1 spent about three months in orbit to survey its landing site. A third mission launched last year by the United Arab Emirates is also currently circling Mars.

“Mars is the planet in our solar system that we are most likely to inhabit in the future. That’s why we want to explore it,” Ge said. “Tianwen-1 will lay the foundation for future Mars missions, including a sample return mission in 2030.”

Editor: Kevin Schoenmakers.

(Header image: China’s Tianwen-1 Mars mission launches at the Wenchang Space Launch Center in Hainan province, July 23, 2020. People Visual)