Spaceflight Insider

Potential Landing Sites for Mars 2020 Narrowed Down to Three

Three Landing Sites for Mars 2020

Three potential landing sites for NASA’s Mars 2020 rover. Image Credit: NASA

The number of potential landing sites for the Mars 2020 rover has been narrowed down to three, from a list of eight, following a conference of scientists last week. The top three landing sites that were selected were in Northeast Syrtis Major, Jezero Crater, and the Columbia Hills in Gusev Crater. The landing sites in the Columbia Hills and Syrtis Major display evidence of geothermal and mineral hot springs that could have been conducive to hosting primitive life, and Jerezo Crater shows evidence that it was once a lake of liquid water.

NE Syrtis Major

Candidate Landing Site in NE Syrtis Major

This image lies in the middle of a candidate landing site in the Northeast part of Syrtis Major, a huge shield volcano, and near the Northwest rim of Isidis Planitia, a giant impact basin. Image & Caption Credit: NASA / JPL-CALTECH / MSSS / JHU-APL

Northeast Syrtis Major was once influenced by volcanic activity that warmed underground sources of water ice that reached the surface as mineral hot springs. These hot springs could have hosted microbial life similar to organisms that have been found in similar environments on Earth. The area also displays layered terrain that holds a record of the interactions between water and minerals throughout early Martian history.

Jezero Crater

Chemical Alteration by Water, Jezero Crater Delta

On ancient Mars, water-carved channels and transported sediments to form fans and deltas within lake basins. Examination of spectral data acquired from orbit shows that some of these sediments have minerals that indicate chemical alteration by water. Here in Jezero Crater delta, sediments contain clays and carbonates. The image combines information from two instruments on NASA’s Mars Reconnaissance Orbiter: the Compact Reconnaissance Imaging Spectrometer for Mars and the Context Camera. (Reference: Ehlmann et al. 2008.) Image & Caption Credit: NASA / JPL-CALTECH / MSSS / JHU-APL

Jezero Crater is an example of the on-again/off-again nature of liquid water on Mars. There is evidence that the crater was filled and drained of water on at least two different occasions around 3.5 billion years ago. Channels can be seen leading into and out of the crater, and there is spectral evidence that suggests clay minerals were formed and deposited as sediment in the lake. These clay minerals are similar to the sediments being examined by the Curiosity rover in Gale Crater and could have played host to microbial life.

Columbia Hills

Perched Above Gusev Crater

This approximate true-color image taken by the Mars Exploration Rover Spirit shows a rock outcrop dubbed “Longhorn”, and behind it, the sweeping plains of Gusev Crater. On the horizon, the rim of Gusev Crater is clearly visible. The view is to the south of the rover’s current position. The image consists of four frames taken by the 750-, 530- and 430-nanometer filters of Spirit’s panoramic camera on sol 210 (August 5, 2004). Image & Caption Credit: NASA / JPL-CALTECH / MSSS / JHU-APL

The Columbia Hills were famously explored by the Mars Exploration Rover (MER) Spirit between 2003–2010 where it discovered evidence the area once hosted a hot spring with liquid water similar in composition to hot springs found on Earth. If selected as the final landing site, the Mars 2020 rover would further inspect hot spring sediments to investigate their potential to host life. Mars 2020 will also revisit an outcrop that was visited by Spirit which in a recent analysis by scientists was thought to resemble a fossilized mat of microbial organisms that have been found in similar hot spring sediments on Earth. This particular outcrop represents the strongest evidence for fossilized life to have been found on the Martian surface to date.

The Mars 2020 rover

The Mars 2020 rover is designed to address several key scientific objectives and the effectiveness of the potential landing sites to meet those objectives factored into the selection of the final three landing sites. Those objectives are the following:

  • Characterize the past habitability of Mars.
  • Search for biosignatures in the Martian geologic record
  • Collect and cache samples for possible retrieval by a future spacecraft and return the samples to Earth for further examination.
  • Prepare for a human mission by demonstrating the use of in-situ resource utilization (ISRU) technologies to create propellant and consumable oxygen; to characterize atmospheric dust to understand its effects on human health, and to collect surface weather measurements to validate global climate models.

Additionally, the Mars 2020 landing site must also meet the following criteria:

  • Does the area show signs in the rock record that it once had the right environmental conditions to support past microbial life?
  • Does the area have a variety of rocks and “soils” (or regolith), including those from an ancient time when Mars could have supported life?
  • Did different geologic and environmental processes, including interactions with water, alter these rocks through time?
  • Are the rock types at the site able to preserve physical, chemical, mineral, or molecular signs of life?
  • Is the potential high for scientists to make fundamental discoveries with the samples cached by the rover, if potentially returned to Earth someday?
  • Does the landing site have water resources (water ice and/or water-bearing minerals) that the rover could study to understand their potential use by future human explorers?
  • Can the rover land and travel from place to place without facing significant hazards posed by the terrain?

The three finalist landing sites were selected from an original list of 8 which also included Eberswalde Crater, Holden Crater, Mawrth Vallis, Nili Fossae, and Southwest Melas Chasma. The rover is currently under development and is similar in construction and function to Curiosity and is targeted to launch during the summer of 2020 and landing on Mars in early 2021.



Paul is currently a graduate student in Space and Planetary Sciences at the University of Akransas in Fayetteville. He grew up in the Kansas City area and developed an interest in space at a young age at the start of the twin Mars Exploration Rover missions in 2003. He began his studies in aerospace engineering before switching over to geology at Wichita State University where he earned a Bachelor of Science in 2013. After working as an environmental geologist for a civil engineering firm, he began his graduate studies in 2016 and is actively working towards a PhD that will focus on the surficial processes of Mars. He also participated in a 2-week simluation at The Mars Society's Mars Desert Research Station in 2014 and remains involved in analogue mission studies today. Paul has been interested in science outreach and communication over the years which in the past included maintaining a personal blog on space exploration from high school through his undergraduate career and in recent years he has given talks at schools and other organizations over the topics of geology and space. He is excited to bring his experience as a geologist and scientist to the Spaceflight Insider team writing primarily on space science topics.

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