The Perseverance Rover dropped the first sample cache to be returned to Earth in a future mission. These tubes are full of Martian rocks and dust that can be analyzed in sophisticated laboratories on Earth.
The first cache is in a flat area known as Three Forks. The Perseverance team plans to drop ten of the titanium tubes at the site. This cache will serve as a backup in case the rover does not end its mission in a place that is convenient for the future sample return mission to pick up.
The process took a while partly because the Perseverance control team wanted to be careful with the tube. Perseverance’s Sampling and Caching System spent nearly an hour retrieving the sample from the rover’s underside, giving it one last once-over with the CacheCam, and dropping it three feet onto the Martian surface. Then the control team used a camera at the end of Perseverance’s robotic arm to ensure that the tube had landed intact and hadn’t rolled into a place where it could get squashed by one of the rover’s wheels.
They also wanted to make certain that it hadn’t landed in a position that would make it difficult to retrieve later. During tests of the sample tube depositing technique, the sample tube landed on the flat end that the helicopter-drones are supposed to use to pick the samples up. If that happens to a sample tube on Mars, the mission team has a plan to have Perseverance gently tip it over with its robotic arm.
NASA and the European Space Agency (ESA) are currently collaborating on the sample return mission, which will include a couple of helicopter drones. The future helicopter drones will be capable of retrieving samples from the cache and returning it to a lander. Once the lander has the samples, it can lift off from Mars and rendezvous with an orbiting vehicle that can deliver them back to Earth.
The Perseverance mission included an experimental helicopter drone called Ingenuity, which provided a demonstration of the feasibility of flying on Mars. The little helicopter drone made its first flight on Mars on April 19, 2021. Ingenuity completed its 25th flight on April 18, 2022, as seen in the below video.
NASA and ESA plan to launch the orbiter as early as 2027 and the lander in 2028. The lander will touch down in Jezero Crater, not far from Perseverance Rover’s landing site. A rocket will also land on Mars to provide launch capability for the spacecraft that will rendezvous with the orbiter. If all goes as planned, the mission will bring samples back to Earth as early as 2033.
The samples are valuable because the results of robotic probes’ scientific missions can produce more questions than answers and it takes time to have a follow-up mission approved – if it ever is. The results of a biology-related experiment on the Viking landers caused a lively initial debate over whether Viking found evidence of microbial life on Mars, for instance, though the current general consensus is that the results were the result of chemical reactions that had nothing to do with metabolism.
Since then, Mars missions have focused on determining whether Mars might have ever been suitable for life. They did find evidence that liquid water once existed on Mars, implying that Mars might have once been warmer and had an atmosphere thick enough to support bodies of liquid water like rivers and lakes. Liquid water is also vital for supporting carbon-based life-forms.
Scientists haven’t given up on the possibility of finding past or present life on Mars. One of Perseverance’s objectives is to find signs of past microbial life. Returning the samples to Earth will allow for more flexibility with following up on results than the Viking missions had.
The sample cache that Perseverance deposited gives the sample return mission a backup in case Perseverance ends up in a place that the helicopter drones can’t reach.