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China’s successful launch of Mars mission seals global era in deep-space exploration

Tianwen-1 is the second of three spacecraft set to take off this month for the red planet.

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People watching the Mars probe being launched in south China's Hainan Province

Tianwen-1 is scheduled to arrive at Mars in February.Credit: Xinhua News Agency/Shutterstock

A Chinese spacecraft is on its way to Mars after launching successfully from Hainan Island in southern China. The mission — named Tianwen-1, which means ‘questions to heaven’ — is the country’s first attempt to land on the red planet.

The 5,000-kilogram spacecraft, which contains a lander, orbiter and rover, blasted off from the Wenchang Satellite Launch Center aboard a Chinese Long March-5 rocket at 12:41 p.m. local time on 23 July. Some 36 minutes later, the craft was successfully put on its trajectory towards Mars.

“This is a really ambitious mission driven by science that represents significant progress in China’s space programme, and they should be proud,” says David Flannery, an astrobiologist at Queensland University of Technology in Brisbane, Australia. “There are a lot of other things that could still go wrong, but so far so good,” he says.

Chinese officials have been tight-lipped about many details of Tianwen-1, including the cost and launch preparations. “The Mars mission is very risky, so I understand why managers are keeping quite a low profile,” says Ji Wu, former head of China’s National Space Science Center in Beijing. Ji was chief scientist on China’s earlier attempt to send an orbiter to Mars aboard a Russian spacecraft in 2011, which failed. “It didn’t even depart from Earth’s orbit. That was a very sad story,” he says.

Tianwen-1 is one of three daring missions to the red planet this year. The United Arab Emirates (UAE) launched its Hope orbiter earlier this week, and the United States’ craft — a six-wheeled rover named Perseverance — is likely to launch next week.

Together with the success of the UAE’s orbiter, Tianwen-1 adds weight to a new reality “that Solar System exploration is not the prerogative of the Euro-American world, but a global enterprise”, says geologist Jon Clarke, who is president of the Mars Society Australia based in Canberra. China, India and Japan have previously sent probes into space, including missions to the Moon, Mars, Venus and some asteroids.

Long journey

Tianwen-1 is now coasting through space before it reaches its destination in February. The craft will then spend several months positioning itself for the landing. In April, the orbiter will release the lander and rover into the Martian atmosphere, and these will touch down somewhere on Utopia Planitia — a vast plain littered with volcanic rocks within a large basin, and where NASA’s Viking 2 lander touched down more than three decades ago. If the landing is successful, China will be only the second country after the United States to softly land a rover on Mars, says Flannery. The six-wheeled, solar-powered rover will explore areas of scientific interest.

The orbiter will loop around Mars for an entire Martian year and act as a communication link for the rover, which has a lifetime of around 90 Martian days — the equivalent of some 93 days on Earth.

China’s mission aims to conduct a global survey of the planet, including studying its geological structures, surface characteristics and climate. The orbiter is packed with seven scientific instruments, and the rover has six more. These include several cameras, subsurface radar and a spectrometer.

A magnetic-field detector on the rover could gain valuable insights into Mars’s past magnetic field, which would have shielded the planet from radiation, says Flannery. And its ground-penetrating radar will help discern some of the geological structures just below the surface of the planet, he says.

The designs of the orbiter and rover seem to draw on China’s several successful missions to the Moon, but are significantly larger than previous probes, says Clarke. The mission “promises to be a milestone in Chinese and global exploration of the planet”, he says. “It will mean new and complementary data about Mars from orbit and from a new location on the Mars surface.”

New space powers

Mars has been a major focus of NASA’s space exploration, says Katarina Miljkovic, a planetary scientist at Curtin University in Perth, Australia. “Adding new countries to the mix, like China and UAE, is very exciting,” she says.

Smaller and newer space powers could also create opportunities for science, says Flannery, who helped build NASA’s Perseverance rover. The rover will collect rocks that will one day be brought back to Earth. “Many of the greatest challenges for planetary science in the coming decades will require international cooperation,” he says. The return of samples from Mars will be extremely expensive and technically complex. And the rocks should be studied by experts worldwide, he adds. China has its own plans to bring samples back from Mars by 2030. In some sense, Tianwen-1 is testing all the necessary technology for such a mission, says Flannery.

He hopes the Chinese space agency will share data from Tianwen-1 with the scientific community. China has shared some of its data sets of the Moon, and this should be followed for Mars, he says. “Space belongs to everyone.”

Nature 583, 671 (2020)

doi: 10.1038/d41586-020-02187-7

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