China Finally Tells us What's Going on With its Mars Rover

The Zhurong Rover has sat unmoving and unresponsive on Mars since May 20th, 2022, when one of the planet’s infamous dust storms forced the science team to switch the rover to hibernation mode. It was expected to wake in late December, but has yet to show any signs of activity. Last week, the Rover’s chief designer, Zhang Rongqiao, offered an update on the rover’s status.

“We have not had any communication from the rover since it entered hibernation,” Zhang said. “We are monitoring it every day and believe it has not woken up because the sunlight has not yet reached the minimum level for power generation.”

The culprit is likely the same villain that has ended the careers of many a Martian robot: dust on the solar panels. Dust accumulation killed NASA’s Opportunity rover in 2018, and more recently, forced a premature end to the InSight lander’s data collection mission in 2022. It may have spelled the end for Zhurong too.

“Based on our analysis,” said Zhang, “the most likely possibility is that an unpredictable accumulation of Martian dust has led to a decrease in the power generation capacity, which is insufficient to wake it up.”

Of course, this doesn’t mean the end of the rover’s career for certain. Changing seasons on the red planet are expected to strengthen the Sun’s rays at Zhurong’s location in the near future. A benevolent dust devil might also wipe the solar panels clean. Either of these could bring power levels back within operational norms.

If the overaccumulation of dust is 30 percent higher than engineers had planned for, it might be survivable for Zhurong, causing it to reawaken once the seasons shift. A 40 percent overaccumulation, however, would mean it is unlikely to wake up ever again.

For now, all there is to do is watch and wait.

Zhurong’s path as of March 2022, as seen by the Mars Reconnaissance Orbiter. NASA/JPL/University of Arizona.

Zhurong already spent 358 days active on Mars, far outliving its primary 90-day mission. It traveled just under 2000 meters across Utopia Planetia, a large impact basin in Mars’ northern hemisphere. Zhurong used ground penetrating radar to gather data, discovering evidence that the region was once the site of an ancient ocean. Its other instruments collected weather data, including surface pressure and wind speeds. The rover also found evidence of ‘recent’ water, recent in this case meaning 400,000 years ago.

Zhurong arrived at Mars in tandem with an orbiter, Tianwen-1, which is still in operation and collecting data from orbit above the Martian surface.

As part of the update, Zhang also commented on the next deep space mission in the Tianwen series. Tianwen-2 will be a sample return mission, intended to bring material back from a near-Earth asteroid named 2016 HO3. Tianwen-2 is expected to launch in May 2025.