Here's the best place for explorers to harvest ice on Mars

Water ice, especially any located in the sub-surface, has long been a focal point of Mars exploration efforts. Reasons abound as to why—from the need to grow plants to the need to create more rocket fuel to blast off the planet for a round trip. Most of that effort has focused on the poles of the planet, where most of the water ice has been found.

Unfortunately, these extreme latitudes are also difficult locations for manned missions, due to their slack of sunlight and extremely low temperatures. Now, a team from the Planetary Science Institute (PSI) have mapped the density of water ice in a large chunk of the lower northern hemisphere, in an effort to help narrow down potential human landing sites at more welcoming latitudes.

The project, aptly named the Subsurface Water Ice Mapping (SWIM) of Mars project, focused on a region of the northern hemisphere slightly outside the "ice stabilization zone" that exists above 50 degree latitude in the northern hemisphere. In this zone, the temperatures are cold enough that the ice is most likely stable at the current environmental conditions on Mars.

At these latitudes, the sunlight available to any human mission would be too low to power the necessary life sustaining technology, making it unsuitable for a human landing spot. Farther south, the sun's power increases significantly, making it possible to power life support with solar power in these regions. While SWIM didn't cover the entire northern hemisphere outside of the polar region, it did cover most.

It did so using data from three different sources: the Mars Reconnaissance Orbiter, Mars Odyssey, and Mars Global Surveyor orbiting satellites. Five different types of data from these satellites were fed into a novel data processing algorithm to stitch them together to come up with a fully realized "ice consistency map." These data types included thermal analysis, radar subsurface compositional (dielectric) analysis, geomorphic mapping of periglacial (i.e. area around a glacier or ice sheet) features, neutron spectroscopy, and radar surface analysis.

Even with that abundance of different data sources, the PSI team is still quick to point out that the level of detail completed in this first study is not suitable for selecting a landing site for a future Mars mission. Luckily any such mission is still in the early conceptual stages, so the team has time to study areas of interest in the hemisphere more carefully, and collect further data to build more detailed models of particularly interesting spots.

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That is exactly what they plan to do—the next step of the SWIM project is to both further analyze existing data and collect new data on these sites of interest. With any luck, before any future Mars mission plan moves ahead, they will have a nice detailed ice map of the surface of the northern hemisphere to help choose a landing site.