The Perseverance rover carries 43 sample tubes. These small titanium containers are part of NASA’s Mars 2020 sample-caching system, designed to preserve carefully selected pieces of Martian rock and regolith for possible study on Earth.
Of the 43 tubes, 38 are intended to hold collected samples. The other five are witness tubes. They are used to record possible airborne or environmental contamination around the rover, helping scientists distinguish Martian material from anything introduced by the spacecraft or its surroundings.
The tubes had to be extraordinarily clean because future researchers may search them for chemical clues about ancient habitability or possible past life. They are also engineered to remain sealed and durable during a difficult journey from Mars, although a sample-return mission is still required before laboratories on Earth can examine the material directly.
The number 43 refers to the rover’s total supply, not the number of samples already collected or the number expected to return. That distinction explains why some mission updates mention smaller figures.