New Mapping Tools Will Find Subsurface Water Ice on Mars

Category: Press Release

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October 26, 2023, Tucson, Ariz. – Refined mapping tools that identify subsurface water ice
on Mars will help determine the best targets for robotic and human missions to the planet.

The fourth phase of NASA’s Mars Subsurface Water Ice Mapping (SWIM) project has
generated three maps that show ice in depths of zero to one meter, one to five meters and
deeper than five meters, said Gareth Morgan, SWIM Co-Principal Investigator and Senior
Scientist at the Planetary Science Institute. The project used for the first time data from
HiRISE – the High Resolution Imaging Science Experiment camera onboard the Mars
Reconnaissance Orbiter.

“We have refined the mapping techniques employed by the Mars SWIM project to improve
our understanding of the distribution of subsurface ice. In particular, we have further
constrained the boundary between where ice is present and where it is absent within the
northern hemisphere,” Morgan said. “Our efforts provide a new tool to help future Mars
mission operations prioritize target acquisition. In particular, a major focus of this work
has been to support a future synthetic-aperture radar (SAR) ice mapping mission such as
the proposed International Mars Ice Mapper (I-MIM) concept.”

“Our maps are also important for future landed missions, both robotic and human. Mission
planners looking to study shallow ice can use our maps as part of their landing site
sections,” said Nathaniel Putzig, the other SWIM Co-Principal Investigator. “In the case of
human landing sites, planners will want to identify regions that have adequate ice for
resource extraction to enable life support and fuel generation, as well as to identify
scientifically interesting terrains. With our maps being released publicly, the community
can use them to refine landing site studies.”

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“Of course, safely delivering humans to Mars and ensuring their survival requires many
other considerations beyond in situ utilization of water-ice resources, including landing-
site safety and solar and thermal specifications. Defining such site requirements is beyond
the scope of the SWIM project and would be premature, given that all human Mars mission
plans are still in the conceptual stage,” Morgan said. “We provide a hemispheric perspective
of ice distribution to support initial landing-site studies and enable the community to
explore the range of Martian terrains that host ice.

“In the harsh environment of the Martian surface, ice can act as a radiation shield.
Biosignatures of past life in many ways are more susceptible to ionizing radiation damage
than actual living organisms. So ice could preserve signatures of ancient life,” Morgan said.
“Also if you can melt ice you have water of course, which is believed to be essential to life.
So, in the very big picture, our maps will be of interest to exobiology studies.”

HiRISE has also revealed so-called “polygon terrain,” where the seasonal expansion and
contraction of subsurface ice causes the ground to form polygonal cracks. Seeing these
polygons extending around fresh impact craters that have revealed ice is yet another
indication that there’s more ice hidden beneath the surface at these locations.

In addition to Morgan and Putzig, PSI scientists Matthew Perry, Asmin Pathare, Mathew
Chojnacki and Megan Russell worked on the third SWIM phase, “Subsurface Water Ice
Mapping for I-MIM”. PSI’s Hanna Sizemore, Zachary Bain and Isaac Smith worked on earlier
phases of the Mars SWIM project.

The Mars SWIM project has been funded by NASA through a series subcontracts to PSI from
the Jet Propulsion Laboratory.


Alan Fischer
Public Information Officer
[email protected]


Gareth Morgan
Senior Scientist
[email protected]


Mark V. Sykes
[email protected]


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The Planetary Science Institute is a private, nonprofit 501(c)(3) corporation dedicated to
Solar System exploration. It is headquartered in Tucson, Arizona, where it was founded in
1972. PSI scientists are involved in numerous NASA and international missions, the study of Mars
and other planets, the Moon, asteroids, comets, interplanetary dust, impact physics, the
origin of the Solar System, extra-solar planet formation, dynamics, the rise of life, and other
areas of research. They conduct fieldwork on all continents around the world. They also are
actively involved in science education and public outreach through school programs,
children’s books, popular science books and art. PSI scientists are based in 30 states and the District of Columbia.