Where should future astronauts land on Mars? Follow the water

So you want to build a base on Mars. Where to start? Like any human settlement, it would be best located near accessible water. Water will not only be crucial for survival supplies, but it will be used for everything from farming to producing the rocket propellant that astronauts will need to return to Earth.

Getting all that water to Mars would be expensive and risky. That’s why NASA has hired scientists and engineers since 2015 to identify deposits of Martian water ice that might be within reach of astronauts on the planet’s surface. But, of course, water also has enormous scientific value: if current microbial life can be found on Mars, it would likely be in close proximity to these water sources as well.

A new study published in Nature astronomy includes a comprehensive map detailing where water ice is most and least likely to be found in the northern hemisphere of the planet. Combining 20 years of data from NASA’s Mars Odyssey, Mars Reconnaissance Orbiter, and the now inactive Mars Global Surveyor, the document is the work of a project called Subsurface Water Ice Mapping, or SWIM. The SWIM effort is led by the Planetary Science Institute in Tucson, Arizona, and managed by NASA’s Jet Propulsion Laboratory in Southern California.

“The next frontier for Mars is for human explorers to descend below the surface and look for signs of microbial life,” said Richard Davis, who is leading NASA’s efforts to find Martian resources to send humans to the sea. red planet. “We realize that we need to create new maps of underground ice to improve our knowledge of where this ice is found both for scientific discovery and to have local resources that astronauts can rely on.

In the near future, NASA plans to hold a workshop for multidisciplinary experts to assess potential human landing sites on Mars based on this research and other scientific and engineering criteria. This mapping project could also inform investigations of future orbiters that NASA hopes to send to the Red Planet.

NASA recently announced that, along with three international space agencies, the signing of a declaration of intent to explore a possible concept of the international Mars Ice Mapper mission. The declaration brings together the agencies to create a joint concept team to assess the potential of the mission as well as partnership opportunities between NASA, Agenzia Spaziale Italiana (the Italian Space Agency), the Canadian Space Agency and the Agency. Japanese aerospace exploration company.

Location, location, location

Ask scientists and engineers on Mars where the most accessible underground ice is, and most will point to the area below Mars’ polar region in the northern hemisphere. On Earth, it is in this region that we find Canada and Europe; on Mars, it includes the plains of Arcadia Planitia and the glacial valleys of Deuteronilus Mensae.

These regions represent a happy medium between where to find the most water ice (the poles) and where to find the most light and heat (the equator). The northern mid-latitudes also offer favorable altitudes for landing. The lower the elevation, the more opportunity a spacecraft has to slow down using the friction of the Martian atmosphere as it descends to the surface. This is especially important for human-class heavy landers, as Mars’ atmosphere is only 1% as dense as that of Earth and therefore offers less resistance to incoming spacecraft.

“Ultimately, NASA tasked the SWIM project with figuring out how far from the equator you can travel to find underground ice,” said Sydney Do, head of the Mars Water Mapping Project. at JPL. “Imagine we had drawn a wavy line across Mars representing this ice boundary. This data allows us to draw this line with a thinner pen instead of a thick marker and focus on the more parts of that line. close to the equator. “

But knowing if a surface is hiding ice is not easy. None of the instrument data sets used in the study were designed to directly measure ice, said Gareth Morgan of the Planetary Science Institute, co-lead of the SWIM project and lead author of the article. Instead, each orbiter instrument detects different physical properties – high concentrations of hydrogen, high speed of radar waves, and the rate at which temperature changes on a surface – that can suggest the presence of ice.

“Despite 20 years of data and a fantastic range of instruments, it’s difficult to combine these data sets because they’re all so different,” Morgan said. “That’s why we assessed the consistency of an ice signal, showing areas where multiple datasets indicate the presence of ice. If all five data sets indicate ice, bingo.

If, say, only two of them did, the team would try to determine how consistent the signals were and what other materials might be creating them. While the different datasets don’t always match perfectly, they often complement each other. For example, current radars look deep underground but do not see the top 30 to 50 feet (10 to 15 meters) below the surface; a neutron spectrometer on board an orbiter measured hydrogen in the top layer of the soil but not below. High-resolution photos have revealed ice being thrown to the surface after recent meteorite strikes, providing direct evidence to supplement radar and other remote sensing indicators of water ice.

Next steps

As Mars experts examine these new underground ice maps, NASA is already considering next steps. On the one hand, blind spots in the currently available data can be addressed by sending a new radar mission to Mars that could focus on the areas of greatest interest to human mission planners: water ice in the upper layers. from the basement.

A future radar-focused mission targeting the near surface could also tell scientists more about the mixture of materials found in the layer of rock, dust and other materials found on the ice. Different materials will require specialized tools and approaches to dig, drill, and access water ice deposits, especially in the extreme Martian environment.

Mapping efforts in the 2020s could help make human missions to Mars possible as early as the 2030s. But before that, there will be a heated debate about the location of humanity’s first outpost on Mars: a a place where astronauts will have the local water ice resources needed to maintain them while being able to make valuable evolutionary discoveries. rocky planets, habitability and potential for life on worlds beyond Earth.