One key activity for NASA's Perseverance Mars rover will be to collect samples of Martian rock and regolith (broken rock and dust). The samples will be collected and brought to Earth by a future mission.
Because scientists want to be confident that any signs of ancient life they might observe in samples returned to Earth are from Mars, not Earth, Perseverance's Sample Caching System -- including the tubes the samples go in -- had to be the cleanest set of components humankind has ever launched into space. NASA’s Jet Propulsion Laboratory met the challenge.
A future mission, which involves a collaboration between NASA and the European Space Agency, will return the samples to Earth. The Perseverance rover is set to land on the surface of Mars on February 18, 2021.