NASA’s SWIM Project Reveals Detailed Maps of Buried Ice on Mars

The map could help the agency decide where the first astronauts to the Red Planet should land. The more water available, the fewer missions need to be undertaken.

Buried ice will be an important resource for the first humans to set foot on Mars, serving as drinking water and a key ingredient in rocket fuel. But it would also be a big scientific goal: Astronauts or robots could someday drill ice cores as scientists do on Earth, uncovering Mars’ climate history and exploring potential habitats (past or present) for microbial life.

The need to search for ice beneath the surface arises because liquid water is unstable on the surface of Mars: The atmosphere is so thin that water instantly evaporates. There is a lot of ice at Mars’ poles – most of it is made of water, although carbon dioxide, or dry ice, can also be found – but the region is too cold for astronauts (or robots) to survive for long.

This is where the NASA-funded Subsurface Water Ice Mapping project comes into play. SWIM, as is known, recently released its fourth series of maps – the most detailed since the project began in 2017.

Led by the Planetary Science Institute in Tucson, Arizona, and managed by NASA’s Jet Propulsion Laboratory in Southern California, SWIM collects data from several NASA missions, including the Mars Reconnaissance Orbiter (MRO), Mars Odyssey 2001, and the now-dormant Mars Mission. Global Surveyor. Using the combined data sets, scientists have identified the most likely places to find surface-accessible Martian ice for future missions.

Instruments on the spacecraft have detected what appears to be a mass of frozen water beneath the surface along Mars’ mid-latitudes. The northern mid-latitudes are particularly interesting because they have a thicker atmosphere than most other regions of the planet, making it easier to slow down a descending spacecraft. The ideal astronaut landing location is at the southernmost tip of this region – far enough north that there is ice, but close enough to the equator to ensure the hottest temperatures for astronauts in the ice region.

“If you send humans to Mars, you want to put them as close to the equator as possible,” said Sydney Do, JPL’s SWIM project manager. “The less energy you have to expend keeping astronauts and their support equipment warm, the more energy you have for other things they need.”

Building Better Maps

Previous iterations of the map relied on imaging, radar, thermal mapping and lower-resolution spectrometers, all of which can provide clues to buried ice but cannot directly confirm its presence or quantity. For this latest SWIM map, scientists relied on two higher resolution cameras at MRO. Context Camera data was used to further refine the Northern Hemisphere map and, for the first time, HiRISE (High Resolution Imaging Science Experiment) data was combined to provide the most detailed perspective of the ice extent line as close to the equator as possible.

Scientists routinely use HiRISE to study new impact craters caused by meteoroids that may have dug up chunks of ice. Most of these craters are no more than 33 feet (10 meters) in diameter, although in 2022 HiRISE captured a 492-foot (150-meter) wide impact crater that revealed masses of ice hiding beneath the surface. .

“The impact of these ice revelations provides a valuable form of ground truth because it shows us locations where the presence of ice on the ground is beyond doubt,” said Gareth Morgan, SWIM co-leader at the Planetary Science Institute. “We can then use these locations to test whether our mapping methods are correct.”