Science Merit Related to Mission Objectives:

The Mars 2020 mission will explore a site likely to have been habitable, seek signs of past life, fill a returnable cache with the most compelling samples, take the first steps towards in situ resource utilization on Mars, and demonstrate technology needed for the future human and robotic exploration of Mars. A more detailed description of the proposed mission objectives can be found in the Mars 2020 Annoucement of Opportunity [NASA AO] and the SDT report [Mustard et al., 2013]. The science requirements for caching are the most demanding and will likely govern the landing site selection process.

Science Criteria [this is UPDATED information for the 3rd Workshop]:

Science criteria on potential 2020 landing sites are based on the findings of the Mars 2020 SDT [Mustard et al., 2013]. All potential landing sites must meet the threshold geological criteria (TGC)to be retained for further consideration. The potential qualifying geological criteria will be used to rank sites that meet the TGC.

Fact sheets for each of the eight candidate sites can be downloaded below.

Columbia Hills
Holden Crater
Jezero Crater
Mawrth Valles
Southwest Melas
Northeast Syrtis
Nili Fossae

In addition, the JMARS developers have set up a path for the 2020 session file: The link is the same for all 8 landing sites since they are all in the same session file. After downloading the session a user can click on the session file to run JMARS or open JMARS the normal way and click file -> load session.

Criteria used to aid in landing site selection are posted below and are available here.

Landing Site Down-Select at the 3rd Mars 2020 Landing Site Workshop


Undoubtedly the most consequential remaining decision for the Mars 2020 mission is the choice of landing site. In the 3rd workshop we sought the critical insight of community members to identify and evaluate the virtues, uncertainties, strengths, and weaknesses of candidate landing sites as input to the process by which three sites were prioritized for further consideration.


Presentations at the workshop provided background information relevant to landing site selection, engineering considerations, and detailed geologic data and interpretations regarding the eight candidate sites. These presentations were thought provoking and lead to healthy collegial discussion that educated the difficult selection process.

At the end of the workshop, attendees were surveyed using a five-point scale on each of the criteria listed below for each of the landing sites. The survey data were tallied to generate a red-yellow-green, qualitative “stoplight” chart for each of the criteria at each site. This chart was displayed and discussed as the final agenda item at the workshop and used as input to a meeting of the Mars Landing Site Steering Committee, the Mars 2020 PSG, and the Mars 2020 Project. These meeting participants used this community input along with their sense of mission objectives and priorities to prioritize three of the eight candidate sites for further scientific and engineering consideration.


Landing site prioritization is fraught with differing and deeply held opinions effected by personal experience, scientific taste, and varying interpretations of existing data. Because Mars 2020 is the first step in a possible Mars sample return effort, this decision has the potential to be among the most influential in the history of planetary exploration. As we continue to engage in this complex and important process together, we ask you to take the long view, carefully consider all of the various stakeholders, and work with us to make the best assessment possible for the science of today and for future generations.

The Criteria listed below were developed by Mars 2020 Project Science and were endorsed by the Mars 2020 Project Science Group. The criteria are designed to be as simple as possible, and to allow differing opinions to be developed, communally explored, and recorded.

Criterion 1:

The site is an astrobiologically-relevant ancient environment and has geologic diversity that has the potential to yield fundamental scientific discoveries when it is a) characterized for the processes that formed and modified the geologic record; and b) subjected to astrobiologically-relevant investigations (e.g., assessment of habitability and biosignature preservation potential). (scoring: 1=lowest potential, 5=highest potential)

Criterion 2:

A rigorously documented and returnable cache of rock and regolith samples assembled at the site has the potential to yield fundamental scientific discoveries if returned to Earth in the future. (scoring: 1=lowest potential, 5=highest potential)

Criterion 3:

There is high confidence in the assumptions, evidence, and any interpretive models that support the assessments for Criteria 1 and 2 for the site. (scoring: 1=lowest confidence, 5=highest confidence).

Criterion 4:

There is high confidence that the highest-science-value regions of interest at the site can be adequately investigated in pursuit of Criteria 1 and 2 within the prime mission. (scoring: 1=lowest confidence, 5=highest confidence).

Criterion 5:

The site has high potential for significant water resources that may be of use for future exploration—whether in the form of water-rich hydrated minerals, ice/ice regolith or subsurface ice. (scoring: 1=lowest potential, 5=highest potential).


Landing Site Workshop: John Grant (, Matthew Golombek (