Tianwen-1

Tianwen-1 is usually described as China's first Mars mission, which is not quite right. China's first Mars spacecraft was Yinghuo-1, a 115 kg orbiter that rode with Russia's Phobos-Grunt in November 2011 and never left Earth orbit when the Russian craft's propulsion failed to fire. Tianwen-1 was the second attempt and the first China flew on its own launcher, its own trajectory and its own deep-space network. It left Wenchang on 23 July 2020 at 04:41:15 UT on a Long March 5, weighing about five tonnes, and took 202 days and roughly 475 million kilometres to reach Mars with four mid-course corrections and one deep-space manoeuvre along the way. The name is taken from Heavenly Questions, a poem by Qu Yuan written more than two thousand years ago, in which the poet interrogates the sky about the origins of everything. On 10 February 2021 the braking burn began at 19:52 Beijing time and China had its first artificial satellite of another planet. NASA's catalogue times the event about 26 minutes later, at 20:18 Beijing, because that figure is Earth-received time at the end of a 14 to 15 minute burn: the burn duration plus the 10 minute 40 second one-way light delay accounts for the whole gap. Light time alone does not. The two numbers are not in conflict; they measure different ends of the same radio link, which is worth knowing before treating either as the arrival time.

What made Tianwen-1 unusual was the combination. Nearly every Mars programme has built up in steps: orbit first, then land, then rove, with years between. The Soviet Union tried to compress that in 1971 with the Mars 2 and Mars 3 pairs, each an orbiter carrying a descent module with a small tethered rover called PrOP-M, and it went badly: Mars 2's capsule crashed, Mars 3's landed and stopped transmitting after about twenty seconds, and no PrOP-M was ever deployed. Tianwen-1 attempted the same architecture and completed it. The step that made it credible was patience. After capture the spacecraft did not go straight for the surface; it changed its orbital plane on 15 February 2021, settled into a parking orbit of about 280 by 59,000 kilometres on 24 February, and spent roughly three months photographing the pre-selected landing region with its high- and medium-resolution cameras before committing. The entry capsule then separated and came down on 14 May 2021 at 23:18 UT, running about nine minutes of fully autonomous entry, descent and landing: trim flaps, parachute, heat-shield and backshell separation, powered descent, a hover while it looked for hazards, then a slow descent onto a damping landing platform. On 22 May the Zhurong rover drove down the ramp.

The orbiter then had a mission of its own, and it is the half that outlived everything else. On 8 November 2021 it moved into a remote-sensing orbit of roughly 275 by 10,749 kilometres inclined 86.3 degrees, a near-polar path that took about seven hours to complete. NASA's catalogue records it more loosely as 265 by 12,000 kilometres. From there it did two jobs at once: relaying Zhurong's data to Earth and mapping the planet itself. By June 2022 its medium-resolution camera had covered the entire surface and all seven instruments had completed global surveys, and on 24 April 2023 CNSA and the Chinese Academy of Sciences released the resulting global image map at 76 metres per pixel. Along the way it photographed Phobos and released small deployable cameras that photographed it in flight. On 1 December 2021 CNSA and ESA jointly announced a successful relay communication test between ESA's Mars Express and the Zhurong rover, one of the few concrete pieces of China-Europe cooperation at Mars; the orbiter's own contribution there was the relay link it normally provided. None of this appears in JPL Horizons, whose Tianwen-1 entries are all reconstructions by volunteer trackers and stop on 21 March 2021. That tells you what China publishes to the American ephemeris service; it tells you nothing about the spacecraft, and confusing the two is an easy way to declare a working orbiter dead.

The clearest evidence that it is not dead is recent and official. On 6 November 2025 CNSA announced that the orbiter's high-resolution camera had imaged 3I/ATLAS, the third interstellar object identified in the Solar System, from about 28.96 million kilometres on 3 October 2025, which the release calls the first attempt to photograph so distant and faint a target with a camera built for the bright Martian surface and one of the closest-range observations any probe made of the object; the release noted the probe had been running stably for four years and eight months and framed the exercise as a rehearsal for the Tianwen-2 asteroid mission. On 20 May 2026 CNSA published the scientific result, an Astrophysical Journal Letters paper led by the National Astronomical Observatories with the Tianwen-1 team, Sun Yat-sen University, the Macau University of Science and Technology, the Shanghai Astronomical Observatory and Chile's Universidad Diego Portales. Because the comet passed within 0.194 astronomical units of Mars in October 2025 and Tianwen-1 could view it from the south side of its orbital plane at 35 to 45 degrees, a geometry unavailable from Earth, the team could separate dust grains under different levels of solar radiation pressure: hundreds of microns across, ejected at about 3 to 10 metres per second, at roughly a tonne a second. The release's closing paragraph opens with a sentence worth quoting for its plainness: this fully demonstrates that the Tianwen-1 orbiter is running stably and in good condition.

So where does that leave the mission on 3 September 2026? The rover is silent and has been since 2022. The orbiter is working, on the evidence of the CNSA statement of 20 May 2026 and an April 2026 agency briefing that described the mission as still conducting global and regional exploration and put the volume of publicly released science data at 3.5 terabytes. Beyond that the picture gets murkier, and one claim in particular should be treated with care: several Chinese self-media posts and a Baidu AI summary assert that the orbiter lost contact on 14 April 2026 and recovered after 63 days on 16 June 2026, and that it will be retired on 24 September 2026. We found no news outlet and no CNSA page carrying any of that, we looked again on 3 September 2026 and still found none, and it sits badly against CNSA's own 20 May 2026 statement, which falls inside the supposed outage. We report it here only because it circulates. What is documented is that the orbiter has now outlived its rover by more than four years, and that its most-cited recent work was done on a target nobody planned for.