Zhurong

Zhurong came down in southern Utopia Planitia on 14 May 2021 at 23:18 UT, which was breakfast time on 15 May in Beijing. The descent ran for about nine minutes with no human input and no possibility of any, because the signal delay made intervention impossible: trim flaps deployed, a parachute opened, the heat shield and then the backshell fell away, a throttled engine took over, the capsule hovered while it looked for a clear patch, then descended slowly onto a damping landing platform. Where exactly it ended up was worked out afterwards. Using sub-metre images from the Tianwen-1 orbiter's High Resolution Imaging Camera, Liu Jianjun, Li Chunlai and colleagues placed it at 109.925 degrees east, 25.066 degrees north, at an elevation of 4,099.4 metres below datum, and published the fix in Nature Astronomy on 6 December 2021. That is a measured position rather than an estimate, which distinguishes Zhurong from most of the Soviet hardware on Mars. The site sits near the boundary between the southern highlands and the northern lowlands, in a region marked by features that several groups have read as ancient shorelines. Six days after landing the rover finished its checks, and on 22 May at 02:40 UT it drove down the ramp, photographed the platform it had arrived on, and set off south.

The design mission was 90 sols. Zhurong hit that mark on 15 August 2021 with 889 metres behind it and every instrument working, and then simply kept going. It carried six payloads: navigation and terrain cameras, a multispectral camera, a laser and shortwave infrared composition detector called MarSCoDe, a ground-penetrating radar, a magnetometer and a small weather station. The pattern of each sol was routine and productive. Cameras imaged the terrain along the way, the radar and weather station ran while driving, the magnetometer took a reading at each navigation point, and anything interesting enough, a rock, a dune, a crater rim, a trough, got a stop and a close look from the composition detector and the multispectral camera. Nothing was wrong during the month-long silence from late September to late October 2021. It was planned: Mars passed behind the Sun and both rover and orbiter waited it out in safe mode. By 15 May 2022, one Earth year on the surface, Xinhua reported 356 sols worked, 1,921 metres driven and about 940 gigabytes of raw science data returned by the mission as a whole. The rover was four times past its design life and still healthy.

Then winter arrived. Xinhua's May 2022 report already described the conditions: daytime highs in the rover's area falling below minus 20 Celsius, nights reaching minus 100, dust storms becoming frequent, sunlight weakening as the Sun dropped in the sky, and heating demand rising at exactly the moment power was falling. The design called for a winter mode, and on 18 May 2022, at 358 sols, Zhurong put itself to sleep. It was supposed to wake itself around December. Nearly a year later, on 25 April 2023, Zhang Rongqiao, chief designer of China's planetary exploration programme, sat down with CCTV and explained precisely what had to happen for that: the rover's internal temperature had to rise above minus 15 Celsius and its solar panels had to generate 140 watts, the minimum it needed to run for a day. Both conditions together, and it would switch itself on. Neither the season nor the sunlight was the problem by then. The most likely cause, he said, was unforeseen dust accumulation on the panels. He then did something unusual for a mission spokesperson and gave the numbers: dust beyond roughly 20 per cent of the design allowance and the panels would not make enough power, beyond 30 per cent and only peak sunlight would do it, beyond 40 per cent and the rover would never wake at all.

That interview is why Zhurong belongs in the same category as Spirit, Opportunity and InSight rather than with the failures. Nothing broke. The rover completed its mission, quadrupled its life, followed its own power-management logic exactly as designed, and lost a slow argument with Martian dust that its engineers had explicitly anticipated and quantified in advance. Zhang was blunt about it: the team had treated the winter survival as an attempt, and the rover not waking was within their expectations. CNSA has never issued a formal end-of-mission declaration, which is why some trackers still list Zhurong as dormant rather than finished; four years of silence through multiple Martian springs makes the distinction academic. What has not stopped is the science. Zhurong's shortwave infrared spectra produced the first in-situ detection of hydrated minerals on Mars by a rover-mounted instrument, hydrated-sulphate-rich duricrust that argues for relatively recent liquid water at the site. Its radar revealed buried polygonal terrain and, in a result CNSA announced on 3 March 2026, a low-loss layer about seven metres thick at roughly fifteen metres depth, interpreted as dirty ice, in a mid-latitude basin where shallow ground ice was not expected. A rover that stopped moving in 2022 was still making news in 2026.

One number about Zhurong is genuinely unsettled, and it is the headline one. The 1,921 metres that appears everywhere, including in Zhang Rongqiao's own account, is the reading from the onboard odometer, which counts wheel rotations. Wheels slip, especially downhill on loose Martian regolith, and an odometer that trusts them will read short. In March 2025 the Planetary Mapping and Remote Sensing Laboratory at the Chinese Academy of Sciences Aerospace Information Research Institute published an outreach piece on the visual localisation and terrain mapping done for Zhurong, reconstructing the traverse from overlapping stereo panorama images rather than from wheel counts. The Chinese Academy of Sciences reported in April 2025 that this method gives 2,009 metres, 88 metres more than the odometer, the discrepancy caused by wheel slippage due to the downslope trend of the traverse, in a study published in the IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. The mission's published 1,921 metres therefore stands as the odometer figure of record, with 2,009 metres as the image-based reconstruction of the same drive. Anyone citing a single number for how far Zhurong drove should know that at least two exist and that they measure different things.