The as-yet-unnamed Tianwen-1 rover is the size of a small golf cart and one-quarter the weight of NASA’s Perseverance. The solar-powered rover is expected to operate for at least 90 days.
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NASA’s Perseverance rover may have company on the Red Planet. China aims to leap to the front ranks in planetary exploration with an ambitious Mars mission, its first independent bid to reach the planet. Tianwen-1—“quest for heavenly truth”—consists of not only an orbiter, but also a lander and a rover, a trifecta no other nation has accomplished on its first Mars bid. “A successful landing would put China among elite company,” says Mason Peck, an aerospace engineer at Cornell University.
Due to launch in July, the mission, if successful, would mark dramatic progress for China’s space program. In recent years it has fielded several lunar landers but made only one attempt on Mars, an orbiter that piggybacked on a failed 2011 Russian mission to the martian moon Phobos.
A Mars landing is among the most challenging feats in spaceflight. Unlike the Moon, Mars has an atmosphere, which means landers need protection from the heat generated during descent. But its air is too thin for a parachute alone to slow a lander; retrorockets are needed as well. And the entire sequence must be executed autonomously. Of 18 lander or rover missions to Mars, only 10 have been successful. Nine of those 10 were NASA missions. A Russian probe landed successfully, but almost immediately lost communications.
Scientists involved in Tianwen-1 said they did not have permission from the China National Space Administration (CNSA) to speak to the press, and the agency did not respond to questions. Although state media have run stories about the mission, there is nothing like the fanfare that accompanies a NASA Mars landing. Several sources within China’s space community believe the agency is muting publicity to temper expectations for a risky mission.
China has not yet announced which of two candidate landing sites it prefers. Both are flat, smooth plains not far from where NASA’s Viking 1 and Viking 2 landers touched down in 1976. The low-lying sites give the lander’s parachute more time to work. Although scientists might have preferred a more rugged site at higher elevations with more interesting geology, “I speculate [CNSA engineers] are looking to particularly demonstrate a safe landing,” says Jim Bell, a planetary scientist at Arizona State University, Tempe, and veteran of several Mars rover missions.
Landing is not the only objective, however. “Our goal is to explore and gather as much scientific data as possible,” CNSA chief mission architect Zhang Rongqiao said during a July 2019 lecture on the mission. The orbiter aims to study the martian magnetic field and atmosphere. With a high-resolution camera, it will map the surface and characterize its geology.
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The as-yet-unnamed, 240-kilogram rover, the size of a small golf cart and one-quarter the weight of Perseverance, carries six scientific instruments. Among them is a ground-penetrating radar (GPR) that, along with one on Perseverance, will be the first such devices on Mars, able to map subsurface features that orbiting radars see only dimly. “You can really investigate layering, structures, and the presence of permafrost or ice,” says Elena Pettinelli, a geophysicist at Roma Tre University, who has helped analyze GPR data from China’s Chang’e 3 and 4 missions to the Moon.
Tianwen-1 will take 7 months to reach Mars, and it will be several more months before the orbiter releases the lander, according to a 2017 paper outlining the mission in Science China Technological Sciences. After trundling off a ramp on the lander, the solar-powered rover is expected to operate for at least 90 martian days, using the orbiter as a communications relay. The orbiter will keep going for about one martian year, or roughly 23 months.
Dean Cheng, a China policy expert at the Heritage Foundation, a conservative U.S. think tank, says beyond demonstrating technological prowess, China wants to contribute “to the global pool of knowledge.” It believes “great powers are also scientific powers,” he says.
Tianwen-1 is not the only upcoming demonstration of those ambitions. Later this year, China plans to launch its Chang’e 5 mission, which would return the first Moon rocks since the last Soviet Union Luna mission in 1976; it will likely attempt a far-side sample return mission after that.
CNSA officials have suggested that if Tianwen-1 and Chang’e 5 go well, China could attempt to return samples from Mars beginning around 2030. That timeline puts it on the heels of the NASA–European Space Agency sample return mission—but not by much.
With reporting by Bian Huihui.