Rover builds Mars rock cache for return plan.

The article reports on a Mars rock sample cache system assembled by U.S. National Aeronautics and Space Administration's (NASA) Perseverance rover to collect rock samples on the planet for the proposed Mars Sample Return (MSR) mission to study these organic-rich rocks on Earth. Topics include the objective of the rover team to learn whether the organic rocks were made by living things, details of the Plan A of the MSR mission and the significance of establishing sample cache as a backup plan.