One of the mission objectives of the Perseverance Mars rover is to retrieve samples from Martian rocks and soil and keep them until a future mission retrieves them. The retrieval missions are still at the early proposal stages, but Perseverance has already collected its samples. Some are stored in the robot’s body. and the rest are dropped on the surface of Mars in case the robot fails in some way that it can’t hand over its samples to another robot that’s going to collect it.
Over the past few weeks we’ve seen Perseverance send back photos of dropped sample tubes that look like little lightsabers over the surface of Mars.
Here is a video of what a proposed sample return mission might look like, from Jet Propulsion Laboratories.