Tianwen-3 — Mars sample return bid

China's round-trip bid to bring Martian soil home — potentially the first Mars sample return.

The story

Tianwen-3 is China's planned Mars sample return mission. The goal is to collect soil and rock from the Martian surface and deliver it to Earth, which would put Martian material in a laboratory for the first time. Launch is planned for late 2028, with the samples arriving back on Earth some years after that.

The architecture splits into two packages. One is a lander paired with an ascent vehicle, which touches down, gathers material and then lifts off again. The other is an orbiter paired with a return craft, which waits in Mars orbit, takes delivery of the sample container and carries it home. Because the two packages launch separately and meet at Mars, this is not a single launch event.

The hardest step is neither the landing nor the liftoff but the meeting in between. An ascent vehicle rising from Mars has to find the orbiting return craft and hand over the sample canister — an uncrewed rendezvous that has so far only been performed around Earth and the Moon. No robots have yet done it in orbit around another planet.

Collection is understood to combine surface scooping with a drill that pulls a core from below. Details such as the landing site, the final sample mass and the launch sequence are still being refined, and the dates can move. This page will follow the official announcements as they come.

Why it matters

Bringing material home matters because of what the instruments can do. Anything carried on a rover is limited in size and power, while a sample on Earth can be examined by many techniques over decades, and revisited whenever a better method appears. Stored material keeps yielding results long after the mission itself has ended.

Dating is the clearest example. Ages for Martian surfaces have so far been estimated by counting craters, but that scale is calibrated on lunar samples and carries large uncertainty when transferred to Mars. Measuring the radiometric age of actual Martian rock would recalibrate the entire timeline of the planet's geological history.

For any claim about past life, physical samples are in a different category again. Deciding whether organic molecules are genuinely Martian or terrestrial contamination requires cross-checking in several independent laboratories, which no remote instrument can substitute for. That is why contamination control, in both directions, is treated as a core requirement rather than a detail.

How to watch

The launch is a broadcast event. Chinese heavy-lift launches are normally carried live by state media through countdown and ascent, with pad-side footage released alongside. Until the window and the exact time are fixed, though, no coverage schedule exists — and it is worth remembering that this mission does not launch only once.

The orbit-view replay is the clearest way to see the trajectory. Play it forward and the departure orbit stretches outward into an ellipse around the Sun, meeting Mars months later, with the two packages following the same road at different times. It also makes plain why a round trip turns into a multi-year schedule rather than a single journey.

In the real sky, find Mars itself. It is a bright point with an orange cast that barely twinkles compared with the stars around it. It brightens sharply around opposition and fades noticeably afterwards, and that rise and fall is simply the distance between the two planets changing. The same rhythm is why launch windows open only once every couple of years.

Background

China built up to this in stages. Tianwen-1 reached Mars orbit in 2021, landed, and operated a rover, all on a first attempt. At the Moon, Chang'e 5 and Chang'e 6 collected material and brought it home by way of an automated rendezvous and docking in lunar orbit. Tianwen-3 is an attempt to combine those two lines of experience into one mission.

The United States and Europe have worked toward the same goal for years. The Perseverance rover has already collected and sealed samples on Mars and left them waiting for retrieval, but the follow-on mission meant to fetch them is still being reworked over cost and architecture. Which agency actually places Martian material in a laboratory first therefore remains an open question.

Schedules here can move and probably will. Launch windows open only about every two years, so any slip immediately becomes a delay measured in years, and landing-site selection and planetary-protection procedures both have to be settled before flight. Confirmed dates and details will be reflected on this page as they are announced.

FAQ

When does Tianwen-3 launch?

The plan targets late 2028. Mars launch windows open only about every two years, so any slip means waiting for the next one, and the schedule is not yet locked in. The samples are planned to arrive back on Earth several years after launch.

Why bring samples back instead of analysing them there?

Instruments on a rover are limited by size and power, while material on Earth can be analysed repeatedly, by many techniques, in many independent laboratories. Some measurements — precise radiometric dating of rock, for instance — are effectively impossible to perform on the surface.

What is the hardest part of the mission?

The rendezvous in Mars orbit, where the ascent vehicle has to meet the waiting return craft and transfer the sample container. Uncrewed rendezvous and docking have been done around Earth and the Moon, but never yet by robots in orbit around another planet.

Can I watch any of it in the sky?

The launch and the cruise are not naked-eye targets. Watch the launch on a stream and follow the trajectory with the orbit-view replay on this page. Mars itself, though, is easy to spot in the night sky as a bright point with a distinctly orange colour.

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Times and figures are approximate — verify with official sources when planning travel. Simulation uses J2000 mean elements.