The samples that stayed on Mars
Congress defunded Mars Sample Return in January 2026. Perseverance's sealed tubes sit in Jezero while China's Tianwen-3 aims to bring back martian rock by 2031.
Perseverance has spent five years doing the most careful geological fieldwork ever performed off Earth: coring rock in Jezero crater, sealing each core in a titanium tube, documenting exactly where it came from. It flew with 43 tubes, 38 for samples. Ten were laid out on the ground at a spot called Three Forks as a backup depot, finished at the end of January 2023; the rest are still aboard the rover. No approved mission exists to collect any of them.
Mars Sample Return died of cost, and the arithmetic that killed it belongs to its own entry. What is left here is the residue: the appropriations bill signed on 23 January 2026 left the programme unfunded, NASA closed its programme office, and the tubes stayed where they were. ESA's Earth Return Orbiter, built for a rendezvous in Mars orbit that will not now happen, is being picked over for salvage.
The first martian rock delivered to a terrestrial laboratory may well be Chinese. Tianwen-3 is designed to launch in the December 2028–January 2029 window on two Long March 5s — one carrying a lander and ascent vehicle, one an orbiter and Earth-return craft — collect surface material by drill and robotic arm, and be home by 2031. It is a simpler mission than MSR: it lands, grabs what is within reach, and leaves. The samples will not be chosen with anything like Perseverance's care. They will still be the first.
Japan may get there ahead of both. MMX is due to leave Tanegashima on an H3 on 20 October 2026, reach Mars a year later, touch down on Phobos and lift more than 10 grams of regolith home around 2031. Phobos is not Mars, but models of impact ejecta suggest a small fraction of its surface layer was blasted off Mars, so the sample may carry martian material as a bonus.
Underneath all of this is an argument nobody has settled. Bringing unsterilised martian material to Earth falls under COSPAR's most restrictive planetary protection category, which requires a containment facility and a verified break in the chain of contact somewhere in the return path. The facility was never built. The rules for what a human crew — shedding microbes continuously, by definition — may do on the surface have never been written at all.