NASA’s Perseverance rover has dropped the last of 10 sample tubes on the surface of Mars, revealing to humanity “first sample depot on another world.” The rover began depositing titanium tubes with rock and dust samples six weeks ago as part of the Mars return mission to collect material from Mars and bring it back to Earth for further study.

Landing on Mars in February 2021, Perseverance landed in a 45-kilometer-wide bowl known as Jezero Crater with a core mission of searching for signs of ancient microbial life and collecting samples from the Martian environment. Scientists believe that billions of years ago, the Jezero crater contained a river that emptied into a vast lake, which could have provided the necessary environment to support microbial life.

The rover is currently carrying 17 primary samples, which the space agency hopes can eventually be delivered to a sample return lander and returned to Earth. The newly completed monster depot⁠ – located in the Three Forks region of the Jezero Crater⁠ – will serve as a backup cache in case Perseverance is unable to provide its onboard monsters. Each tube’s location has been carefully mapped out so that they can be found and collected by two Ingenuity-like helicopters, even when they’re covered in dust.

While the table is set at Three Forks, Perseverance is reportedly still in good shape and will now embark on an extended mission to explore nearby Delta Top territory. The Delta Top campaign is expected to last about eight months and will explore rocks and sediment that appear to have been brought to the Jezero crater by an ancient river.

The main mission’s focus is now on the future recovery of the Martian samples. Defense contractor Lockheed Martin was commissioned last year to build the Mars Ascent Vehicle (MAV), which is needed to lift off from the surface of the Red Planet – making it the first rocket ever launched from another planet if successful – and passing the collected samples to a spacecraft being built by the European Space Agency, which will then deliver the precious cargo into the hands of eager scientists on Earth.

NASA currently estimates that the sample retrieval lander will not land until 2028 at the earliest, and the collected samples will not arrive on Earth until 2033.

That is of course much easier said than done. The return mission to Mars represents more than a decade of work and requires countless incredibly complex steps to succeed, some of which have never been attempted before, such as landing a rocket on Mars that can take off again. However, if the teams behind the mission can successfully carry out these mammoth efforts, we will be closer than ever to knowing whether life existed beyond our Earth.