Jezero Crater, where Perseverance landed on 18 February 2021, was not chosen at random: the fan-shaped sedimentary structure visible from orbit showed that a river had emptied into a lake here billions of years ago. On Earth, such deltas are the settings where microbial traces are best preserved. The rover seals rock samples in metal tubes and leaves them on the surface; the mission meant to bring those tubes to Earth is still in planning and under budgetary argument. Studying the samples in a laboratory could answer the question of past life far more strongly than measurements made on site.

The mission's second part was Ingenuity, a 1.8-kilogram helicopter. The Martian atmosphere is thinner than one per cent of Earth's, so generating lift required the rotors to spin at 2,500 revolutions per minute. The forty-second first flight on 19 April 2021 was a technology demonstration — five flights were planned; the aircraft made seventy-two before damaging a blade in early 2024. Planetary exploration thereby gained a new mode of movement: terrain a wheeled vehicle cannot climb can now be seen from the air.

The mission also carried MOXIE, an experiment that produced oxygen from carbon dioxide in the Martian atmosphere. The quantity was small, but the principle held: the oxygen a future crewed mission would need can be made on site. The 2020s were not a decade in which only the United States went to Mars — China's Tianwen-1 landed a rover the same year, and the United Arab Emirates' Hope probe entered orbit.