NASA scientists selected the spot on Mars where they plan to land their next rover in 2020 — a region that was likely an ancient river delta on the Red Planet. The spacecraft will aim to touch down in Jezero Crater, an area that may have been habitable billions of years ago. NASA took particular care in selecting this spot to explore; someday, samples collected by the rover could be returned to Earth for study.

This new rover is the successor to the last one that NASA landed on Mars in 2012, known as Curiosity. That robot has been exploring a region on Mars known as Gale Crater, a spot that also was a lot wetter in the past than it is today. Curiosity has learned a great deal about its little slice of Mars over the last six years. It found organic material in the Martian soil and detected methane — a gas mostly produced by life here on Earth. But with the new Mars 2020 rover, NASA hopes to finally get an answer to a long-burning question: did biological life ever actually survive on the Martian surface?

Mars 2020 is designed to be the first step in what is known as a Mars sample return mission

To decipher this, Mars 2020 is designed to be the first step in what is known as a Mars sample return mission. While in Jezero Crater, the robot will dig up tantalizing rock samples that might contain evidence of past life on Mars and store those materials in caches on the surface. Then at some unknown date, NASA will launch a second mission to the Red Planet to collect the Mars 2020 samples and bring them back to Earth. That way we can study these Martian rocks in our own sophisticated laboratories, to truly understand what ancient Mars was like.

A Mars sample return mission is one of the top priorities of the planetary science community right now. It’s also an incredibly difficult type of mission to pull off. To get samples off of Mars, NASA will need to land a bunch of sophisticated technology on the surface of the Red Planet, including a rocket capable of taking off from the ground. That way, the samples will have enough energy to break free of Mars’ gravity and travel through space back to our planet.

So far, NASA doesn’t have a plan for how it’s going to get the Mars 2020 samples off of Mars, but the space agency hopes to launch this follow-up mission in the late 2020s, with a return to Earth sometime in the early 2030s. “I don’t have any updates today,” Thomas Zurbuchen, the associate administrator of NASA’s Science Mission Directorate, said today during a press conference announcing the landing site. “The work is continuing.”

But first, the Mars 2020 rover will select the samples that are most compelling for further research. To pick the perfect place for that, NASA experts and other planetary scientists met in a series of four workshops over the last four years. They were able to narrow down the landing site from more than 60 possible options. Jezero Crater, in the planet’s northern hemisphere was one of four finalist sites. And it ultimately won because of its potential for containing ancient biosignatures — signs of life from long ago.

Perhaps the most attractive aspect of Jezero Crater is that it was once home to flowing water. An asteroid impact may have carved out the site, creating a crater that’s 28 miles wide and more than 1,600 feet deep. Scientists believe the crater was filled with water between 3.5 and 3.9 billion years ago. Inside the crater is a delta, which tells researchers that water flowed into the lake, depositing sediments and other materials into the crater along the way. Since lakes are pretty habitable environments on Earth, that makes Jezero Crater an attractive option. And the flowing water also raises the odds that microbes or other life was transported into the region and got trapped. “The delta is a good place for evidence of life to be deposited and then preserved for the billions of years that elapsed since this lake was present,” Ken Farley, a project scientist on Mars 2020 at NASA’s Jet Propulsion Laboratory, said today during a press conference.

“The delta is a good place for evidence of life to be deposited and then preserved.”

Jezero Crater is also home to a lot of interesting and diverse rocks, which makes it a great place to explore from a geology standpoint. It’s thought to have at least five different types of rock, the most exciting of which is known as carbonate. This kind of rock is created from interactions between water, rock, and gases in the atmosphere like carbon dioxide. Carbonates could hold clues as to what the ancient Mars atmosphere was like billions of years ago. And it also may be another place in which microbes thrived — separate from the lake.

While Jezero Crater boasts some great features for research, the area isn’t exactly the best place to land a spacecraft. There are a lot of boulders and rocks in the area, as well as cliffs and depressions, which will pose a challenge for a vehicle that needs to touch down gently. But the Mars 2020 rover will come equipped with a sophisticated landing routine, like its predecessor Curiosity, including a tether-like contraption known as a sky crane that will lower the vehicle gently to the ground. Engineers have also been able to refine their landing systems in recent years, so that the spacecraft will be able to avoid particularly choppy areas, according to NASA.

There’s still a lot of development that needs to be done to prepare the Mars 2020 rover for its launch. The robot is slated to take off on top of an Atlas V rocket in July 2020, with a landing scheduled for February 2021. In the meantime, NASA is focused on landing another spacecraft on Mars this week — a robot called InSight, which will sit on the surface of the Red Planet and study the world’s interior. InSight has been traveling to Mars since its launch in May and is scheduled to land on Monday, November 26th.