Curiosity is still be working hard on Mars, collecting data and sending it back to Earth for analysis. But scientists and engineers are already looking ahead to year 2020 and the launch of a new Rover, Mars 2020. This week, scientists narrowed down its possible landing zones to three different sites on the red planet.

Mars 2020’s main objective is seek out signs of life and environments that could have once been habitable, writes Elizabeth Howell at Seeker. Since traveling over Mar’s sometimes rugged terrain is slow going for a rover, so its landing spot is key.

The first selection, Jezero Crater, is the most popular scientific target, reports Paul Voosen at Science Magazine. An ancient river delta is visible from orbit, and the area contains the remnants of lakes, which could contain hits of life long gone.

Northeast Syrtis, the second candidate, is the site of an ancient volcano. As Sarah Lewin at Space.com reports, the warmth provided by the volcano could have fostered hot springs and melted ice. These warm little puddles would have been a great spot for ancient microbial life to flourish.

The final selection came as something of a surprise. Rather than picking a new destination, scientists chose Columbia Hills. In 2004, the Mars Spirit Rover landed at the Gusev crater at Columbia Hills and discovered that ancient hot springs once flowed at the site, reports Avery Thompson at Popular Mechanics. Scientists are excited about the opportunity to return to Gusev crater with Mars 2020’s updated tools. Howell reports that an advantage to Columbia Hills is that Spirit has already mapped much of the terrain.

One of Mars 2020’s main is creating a cache of soil and rock samples. In the future, NASA may launch a robotic mission to collect these samples and bring them back to Earth for an extended analysis. Mars 2020 will have the ability to measure the chemical composition and organic content of soils and rock. But bringing samples back to Earth would allow researchers to study the rocks in much greater detail. We’re still running tests on moon rocks retrieved from the lunar missions of the 1960s and 1970s; a Mars sample in Earth laboratories would be invaluable.

The design of Mars 2020 is based on Curiosity, which has been operating on Mars since 2012. Researchers have improved each component, and Mars 2020 will have some additional tools that Curiosity does not, including an experiment to use Mars’s atmosphere to produce oxygen, Howell writes. From our desire to analyze once-habitable environments to producing the air we need to breathe, it’s clear that these rovers are playing a key role in a possible manned mission to Mars.