SETI Institute scientist John Roma (J.R.) Skok is working with NASA to help decide where the Mars 2020 rover could collect samples.

On October 16, the Mars science community is gathering for a three-day meeting near Los Angeles to determine where the next generation of NASA missions to Mars will explore. They will meet for the 4th landing site workshop for the Mars 2020 sample return rover. After decades of landers, rovers and orbiters probing Mars, NASA has decided that the only way to really advance our understanding of Mars is to bring back a handful of samples to be studied in the best labs on Earth.

Mars 2020 will be the first stage of a three mission plan to return samples from the red planet. The rover will collect ~100 grams of carefully selected samples and cache them in a protected container. The Mars mission that will follow Mars 2020 will land near these samples, collect the cache and launch it into orbit around the planet. The third and final mission will then rendezvous with these samples around Mars and launch them back to Earth for study. These last two missions will depend on a successful and worthwhile sample collection by Mars 2020. This puts a lot of pressure to select the perfect landing spot to explore the deepest secrets of Martian history.

The number one goal of the whole mission is to collect potential evidence of ancient life, or biosignatures, as scientists call them. After three previous landing site workshops for Mars 2020, the Mars community has narrowed the options down to three potential sites that represent different ideas for finding biosignatures on Mars, and a fourth hybrid site than combines two of these regions. Each of these sites has been determined to be safe for the mission to land and operate, and they all have the potential to preserve evidence of ancient life.

The finalist sites under consideration include the Columbia Hills, the exploration site for the Mars Exploration Rover Spirit, which explored the region from 2004 to 2010 and found evidence for hot spring sinter deposits, ideal for preserving biosignatures if they were present when it was active, at least 3 billion years ago. The Jezero river delta, a sedimentary lake deposit that would encase potential biosignatures in layers of clay. Or Northeast Syrtis, a region of exposed deep bedrock that might have been where ancient underground life once flourished. A fourth potential site, called Midway, is located between the nearby Northeast Sytris and Jezero sites and would have the potential of visiting terrains from both regions over an extended mission.

I will be presenting at the meeting in favor of Northeast Syrtis, a site that I have been researching for 8 years. Northeast Syrtis represents rocks from the ancient Noachian, the most Earth-like and dynamic times on Mars and a type of environment that previous missions to Mars have not been able to explore because they are usually too rocky or mountainous to land near. My other research focus is on detecting biosignatures in silica hot spring deposits, work that would be directly relatable to a mission to Columbia Hills.

As we go into the final landing site selection, NASA will need to decide the very nature of its mission to explore the Solar System. All three landing site types have entire scientific communities that support it as the best place to find biosignatures. One of the main differences between them will be the philosophical motivation to explore. Columbia Hills is a place that we have visited before with the Spirit Rover. It is a fascinating site, with a lot more to explore with new instruments and return samples. Furthermore, having already imaged the main outcrops, we can plan out exactly which rocks we want to sample before we even get there. However, this mission would still go to a place that we have seen before. Mars has the same amount of dry land area to explore as the Earth, and we have only landed on 7 spots, all them selected to be flat and safe. The more rugged and scientifically interesting places that formed in the earliest time on Mars have yet to be explored in depth at all. Mars 2020 is the first mission with the landing technology to really explore the rugged, ancient rocks of Mars. Should NASA use that technology to go to a compelling, scientifically safe location in the Columbia Hills, or use it to explore fundamentally new terrains that we know are in Northeast Syrtis and Midway and are sampled in the delta of Jezero?

This is the fundamental debate for the mission and the landing site selection. Do we prioritize guaranteed scientific success or gamble it to explore a new place that may revolutionize our understanding of ancient Mars - or may turn out to not have any samples worth returning? NASA must decide if it wants to explore Mars or analyze it.

On a planet as diverse and mysterious as Mars continues to be, I believe we are still in the exploration stage and need to see new lands and the secrets they offer before doubling down on past sites. Mars is big and we are just getting started with it. With luck and a lot of hard work, we can explore the deep history of this fascinating world.

The workshop will be broadcasted live on Adobe Connect. You can listen in to all of the science as it happens on the workshop’s website:

https://marsnext.jpl.nasa.gov/

In the weeks following the meeting, NASA officials will consider all of the input from the scientists, engineers, and community members and make a final decision.