It's been a year since China's first-ever independent interplanetary mission reached Mars, and in that time, Tianwen 1 has made major achievements while also delivering a number of surprises.
The Tianwen 1 spacecraft entered orbit around the Red Planet on Feb. 10, 2021. Shortly after, the China National Space Administration released epic footage of the event, showing the orbiter pass behind Mars as it fired engines to slow down and enter orbit.
Orbiting, however, was only one aspect of the mission. For the next three months, teams on Earth prepared for the landing attempt of the rover that would come to be named Zhurong, with Tianwen 1 altering its orbit and returning detailed, high-resolution images of the target landing site in Utopia Planitia.
Following NASA's Perseverance rover in February, Zhurong went through its own, slightly longer, nine minutes of terror and successfully landed on May 14. The achievement made China only the second country to land and operate a rover on Mars, and heralded the country as a major player in deep space exploration.
"The ability to successfully orbit, descend, land safely and deploy a rover on the first try, is a stunning engineering and operational accomplishment," James Head III, a geologist at Brown University, told Space.com.
Zhurong triumphantly rolled down from its lander and onto the red Martian dust a week after touchdown, following systems checks and scoping out the environment. It also dropped a remote camera so Zhurong could pose for a selfie next to its landing platform partner.
The Tianwen 1 orbiter has spent most of its time since the landing supporting Zhurong, making daily passes overhead to relay data from the rover back to Earth. The orbiter has also returned beautiful crescent views of the Red Planet.
In late September, Tianwen 1 paused its work as the sun blocked communications with Earth; then, in early November, the spacecraft lowered its orbit in order to survey more areas of Mars with its seven science payloads.
The orbiter also dropped two further epic surprises. First, on New Year's Day, by releasing a remote, disposable camera that photographed Tianwen 1 above Mars, and more recently with stunning video footage taken using a selfie stick.
Meanwhile, on the surface, Zhurong has far exceeded its primary mission of 90 Mars sols (92 Earth days) and is traveling south from its landing site. The rover has analyzed a number of geologic features and returned images and panoramas of its adventures, and has covered a total of 5,000 feet (1,537 meters) as of Feb. 4.
Looking ahead, Zhurong could reach features including pitted cones, which may have formed through igneous or sedimentary volcanism, said Mackenzie Mills, a graduate student at the University of Arizona and a co-author of a 2021 paper on the geologic context of Zhurong's landing area.
"Future in situ compositional data from Zhurong could help resolve how cones form by providing evidence supporting a proposed mechanism," Mills told Space.com in an email. "Determining how pitted cones form will help us better understand them and also constrain the past geologic context of Utopia Planitia in which they likely formed."
However, Zhurong will soon need to negotiate winter in the northern hemisphere, when its solar panels can't receive as much light because the sun is lower in the sky. Dust storms may also pose a hazard, as they did for earlier rovers. The seasonal changes could cause problems for Zhurong, Sun Zezhou, a China Mars mission system designer, told Chinese press in January.
Winter solstice will occur in July, however, data the rover has already collected will likely prove important once results are published in science journals.
"The data from the Zhurong rover on possible ancient ocean deposits will provide important perspective on the results from Curiosity and Perseverance, which landed in ancient lakes," Head said.
Tianwen 1, meanwhile, is designed to operate for at least one Martian year, or about two years on Earth, with lots of science to come.