After a half-year journey, China’s Tianwen-1 robotic spacecraft—the country’s first interplanetary mission—today successfully entered orbit around Mars, the China National Space Administration confirmed. The arrival was first reported by amateur radio signal observers, as China declined to provide real-time coverage of the attempt.
Following a 15-minute thruster burn that began at 7:52 p.m. in Beijing, the spacecraft entered a 10-day elliptical orbit around the Red Planet. The success makes China the sixth country or space agency to send a spacecraft to the planet; yesterday, the United Arab Emirates, with its Hope orbiter, became the fifth member of that club. (Next week, on 18 February, NASA’s next Mars rover, the SUV-size Perseverance, will attempt to arrive and land on the planet’s surface at Jezero crater.) The orbital insertion, which follows a flurry of lunar missions, “clearly demonstrates the first-class ability of Chinese engineering and command and control capabilities,” says James Head, a planetary scientist at Brown University.
Tianwen-1—“quest for heavenly truth”—is far from done, however. Although its orbiter carries scientific instruments of its own, including radar to scout for subsurface water and a high-resolution camera, the spacecraft also carries a lander and rover. After nudging the spacecraft into a closer orbit, mission managers will scout the intended landing site at Utopia Planitia, a flat basin in the northern hemisphere that was previously visited by NASA’s Viking 2 lander in 1976. A landing attempt will come in May or June.
Unlike the Moon, where China has previously landed missions, Mars has a thin atmosphere that can burn up lightly armored spacecraft. But the air is too thin to slow a lander with only a parachute, so Tianwen-1’s lander must fire retrorockets at the exact right time to stop its descent. NASA has mastered this complex, autonomous sequence, landing nine missions on the planet’s surface; only one other mission, a short-lived Russian probe, has been similarly successful.
If all goes well, Tianwen-1’s 240-kilogram rover, golf cart–size and solar-powered, will roll down off the lander and operate for at least 90 martian days. The orbiter is expected to last for at least 2 years.