Astronauts Could Use the ScanMars Device to Search for Water on Mars

Analogue astronauts have tested a ground-penetrating radar named ScanMars at a Mar-like area in Oman. Image: OEWF – Austrian Space Forum

There’s solid evidence for the existence of water on Mars, at least in frozen form at the planet’s poles. And a more recent study confirms the existence of liquid water at the south pole. But visitors to Mars will need to know the exact location of usable water deposits at other Martian locations. A ground-penetrating radar called ScanMars may be up to the task.

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Was This Huge River Delta on Mars the Place Where its Oceans Finally Disappeared?

For some time, scientists have known that Mars was once a much warmer and wetter environment than it is today. However, between 4.2 and 3.7 billion years ago, its atmosphere was slowly stripped away, which turned the surface into the cold and desiccated place we know today. Even after multiple missions have confirmed the presence of ancient lake beds and rivers, there are still unanswered questions about how much water Mars once had.

One of the most important unanswered questions is whether or not large seas or an ocean ever existed in the northern lowlands. According to a new study by an international team of scientists, the Hypanis Valles ancient river system is actually the remains of a river delta. The presence of this geological feature is an indication that this river system once emptied into an ancient Martian sea in Mars’ northern hemisphere.

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The Bizarre Picture is a 360-Degree View Around Curiosity on Mars

Ever since it landed on the Red Planet in 2012, the Curiosity rover has showed no signs of slowing down! For the past six years, it has ventured across the Gale Crater, scaled Mount Sharp, and taken numerous drill samples. And in the process, it has found evidence that liquid water (and possibly even life) once existed on the Martian surface.

It has also taken many breathtaking pictures that have catalogued its progress. Last month (on Aug. 9th), the rover took another 360-degree panoramic photo of its location. In addition to showing how the skies were still darkened by the fading dust storm and the rover’s dust-covered body, the picture also captured and the site where the latest drill sample was obtained.

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This is the Habitat in Hawaii Helping Astronauts Preparing to Explore Mars

When it comes time to send astronauts to Mars, those who make the journey will need to be ready for a number of challenges. In addition to enduring about six-months in space both ways, the first astronauts to explore Mars will also need to be prepared to spend months living on the surface. This will consist of long periods spent in a pressurized habitat and regular forays to the surface wearing pressure suits.
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As the Martian Dust Storm Subsides, There’s Still No Word From Opportunity

Martian dust storms are a pretty common occurrence, and generally happen whenever the southern hemisphere is experiencing summer. Though they can begin quite suddenly, these storms typically stay contained to a local area and last only about a few weeks. However, on occasion, Martian dust storms can grow to become global phenomena, covering the entire planet.

One such storm began back in May, starting in the Arabia Terra region and then spreading to become a planet-wide dust storm within a matter of weeks. This storm caused the skies over the Perseverance Valley, where the Opportunity rover is stationed, to become darkened, forcing the rover into hibernation mode. And while no word has been heard from the rover, NASA recently indicated that the dust storm will dissipate in a matter of weeks.

The update was posted by NASA’s Mars Exploration Program, which oversees operations for the Opportunity and Curiosity rovers, as well as NASA’s three Mars orbiters (Mars Odyssey, MRO, and MAVEN) and the Insight lander (which will land on Mars in 109 days). According to NASA, the storm is beginning to end, though it may be weeks or months before the skies are clear enough for Opportunity to exit its hibernation mode.

This global map of Mars shows a growing dust storm as of June 6, 2018. The map was produced by the Mars Color Imager (MARCI) camera on NASA’s Mars Reconnaissance Orbiter spacecraft. The blue dot indicates the approximate location of Opportunity. Image Credit: NASA/JPL-Caltech/MSSS

As noted, dust storms occur on Mars when the southern hemisphere experiences summer, which coincides with the planet being closer to the Sun in its elliptical orbit. Due to increased temperatures, dust particles are lifted higher into the atmosphere, creating more wind. The resulting wind kicks up yet more dust, creating a feedback loop that NASA scientists are still trying to understand.

Since the southern polar region is pointed towards the Sun in the summer, carbon dioxide frozen in the polar cap evaporates. This has the effect of thickening the atmosphere and increasing the surface pressure, which enhances the process by helping suspend dust particles in the air. In some cases, the dust clouds can reach up to 60 km (40 mi) or more in elevation.

Planet-wide dust storms are a relatively rare occurrence on Mars, taking place every three to four Martian years (the equivalent of approximately 6 to 8 Earth years). Such storms have been viewed many times in the past by missions like Mariner 9 (1971), Viking I (1971) and the Mars Global Surveyor (2001). In 2007, a similar storm took place that darkened the skies over where Opportunity was stationed – which led to two weeks of minimal operations and no communications.

While smaller and less intense the storm that took place back in 2007, the current storm intensified to the point where it led to a level of atmospheric opacity that is much worse than the 2007 storm. In effect, the amount of dust in the atmosphere created a state of perpetual night over the rover’s location in Perseverance Valley, which forced the rover’s science team to suspend operations.

Simulated views of a darkening Martian sky blotting out the Sun from NASA’s Opportunity rover’s point of view, with the right side simulating Opportunity’s view in the global dust storm as of June 2018. Credit: NASA/JPL-Caltech/TAMU

This is due to the fact that Opportunity – unlike the Curiosity rover, which runs on nuclear-powered battery – relies on solar panels to keep its batteries charged. But beyond suspending operations, the prolonged dust storm also means that the rover might not be to keep its energy-intensive survival heaters running – which protect its batteries from the extreme cold of Mars’ atmosphere.

Luckily, NASA scientists who have been observing the global event indicated that, as of last Monday (July 23rd), more dust was falling out of the planet’s thin air than was being raised into it. This means that the global weather event has reached its decay phase, where dust-raising events either become confined to smaller areas or stop altogether.

Using its Mars Color Imager (MARCI) and Mars Climate Sounder (MCS), NASA’s Mars Reconnaissance Orbiter (MRO) also noted surface features were beginning to reappear and that temperatures in the middle atmosphere were no longer rising – which indicates less solar heating by dust. The Curiosity rover also noted a decline in dust above its position in the Gale Crater on the other side of the planet.

This is certainly good new for the Opportunity rover, though scientists expect that it will still be a few weeks or months before its solar panels can draw power again and communications can be reestablished. The last time communications took place with the rover was on June 10th, but if there’s one thing the Opportunity rover is known for, it’s endurance!

When the rover first landed on Mars on January 25th, 2004, its mission was only expected to last ninety Martian days (sols), which is the equivalent of about 92.5 Earth days. However, as of the writing of this article, the rover has endured for 14 years and 195 days, effectively exceeding its operational lifespan 55 times over. So if any rover can survive this enduring dust storm, its Opportunity!

In the meantime, multiple NASA missions are actively monitoring the storm in support of Opportunity and to learn more about the mechanics of Martian storms. By learning more about what causes these storms, and how smaller ones can merge to form global events, future robotic missions, crewed missions and (quite possibly) Martian colonists will be better prepared to deal with them.

Further Reading: NASA

Five Teams Compete to Design a 3D Printed Mars Habitat for NASA

If and when we decide to go to Mars (and stay there), the Martian settlers will face some serious challenges. For one, the planet is extremely cold compared to Earth, averaging at about -63 °C (-82°F), which is comparable to cold night in Antarctica. On top of that, there’s the incredibly thin atmosphere that is unbreathable to humans and terrestrial creatures. Add to that the radiation, and you begin to see why settling Mars will be difficult.

But as the saying goes, necessity is the mother of invention. And to stimulate the invention process, NASA has partnered with Bradley University of Peoria to launch the 3D-Printed Habitat Centennial Challenge competition. As part of NASA’s Centennial Challenges, which are sponsored by the Space Technology Mission Directorate, this competition recently awarded $100,000 in prize money to five teams for their design concepts.

The NASA Centennial Challenges were initiated in 2005 to directly engage the public, and produce revolutionary applications for space exploration challenges. The program offers incentive prizes to stimulate innovation in basic and applied research, technology development, and prototype demonstration. To administer the competition, Bradley University also partnered with sponsors Caterpillar, Bechtel and Brick & Mortar Ventures.

For the competition, participants were tasked with creating digital representations of the physical and functional characteristics of a Martian habitat using specialized software tools. A panel of NASA, academic and industry experts awarded the team points based on various criteria, which determined how much prize money each winning team got. Out of 18 submissions from all over the world, 5 teams were selected.

In order of how much prize money they were awarded, the winning teams were:

  1. Team Zopherus of Rogers, Arkansas – $20,957.95
  2. AI. SpaceFactory of New York – $20,957.24
  3. Kahn-Yates of Jackson, Mississippi – $20,622.74
  4. SEArch+/Apis Cor of New York – $19,580.97
  5. Northwestern University of Evanston, Illinois – $17,881.10

The design competition emphasizes all the challenges that building a life-supporting habitat on Mars would entail, which includes the sheer distances involved and the differences in atmosphere and landscapes. In short, the teams needed to create habitats that would be insulated and air-tight and could also be built using local materials (aka. in-situ resource utilization).

The competition began in 2014 and has been structured in three phases. For Phase 1, the Design Competition (which was completed in 2015 with $50,000 prize purse), the teams were required to submit a rendering of their proposed habitat. Phase 2, the Structural Member Competition, focused on material technologies and required teams to create structural components. This phase was completed in 2017 with a $1.1 million prize purse.

For Phase 3, the On-Site Habitat Competition – which is the current phase of the competition – competitors were tasked with fabricated sub-scale versions of their habitats. This phase has five levels of competition, which consist of two virtual levels and three construction levels. For the former, the teams were tasked with using Building Information Modeling (BIM) software to design a habitat that combines all the structural requirements and systems it must contain.

For the construction levels, the teams will be required to autonomously fabricate 3D-printed elements of the habitat, culminating with a one-third-scale printed habitat for the final level. By the end of this phase, teams will be awarded prize money from a $2 million purse. As Monsi Roman, the program manager for NASA’s Centennial Challenges, said in a recent NASA press statement:

“We are thrilled to see the success of this diverse group of teams that have approached this competition in their own unique styles. They are not just designing structures, they are designing habitats that will allow our space explorers to live and work on other planets. We are excited to see their designs come to life as the competition moves forward.”

The winning entries included team Zorphues’ concept for a modular habitat that was inspired by biological structures here on Earth. The building-process begins with a lander (which is also a mobile print factory) reaching the surface and scanning the environment to find a good “print area”. It then walks over this area and deploys rovers to gather materials, then seals to the ground to provide a pressurized print environment.

The main module is then assembled using pre-fabricated components (like airlocks, windows, atmospheric control, toilets, sinks, etc), and the structure is printed around it. The printer then walks itself to an adjacent location, and prints another module using the same method. In time, a number of habitats are connected to the main module that provide spaces for living, recreation, food production, scientific studies, and other activities.

For their concept, the second place team (Team AI. SpaceFactory) selected a vertically-oriented cylinder as the most efficient shape for their Marsha habitat. According to the team, this design is not only the ideal pressure environment, but also maximizes the amount of usable space, allows for the structure to be vertically-divided based on activities, is well-suited to 3-D printing and takes up less surface space.

The team’s also designed their habitat to deal with temperature changes on Mars, which are significant. Their solution was to design the entire structure as a flanged shell that moves on sliding bearings at its foundation in response to temperature changes. The structure is also a double shell, with the outer (pressure) shell separate from the inner habitat entirely. This optimizes air flow and allows for light to filters in to the entire habitat.

Next up is the Khan-Yates habitat, which the team designed to be specifically-suited to withstand dust storms and harsh climates on the Red Planet. This coral-like dome consists of a lander that would set down in the equatorial region, then print a foundation and footing layer using local materials. The print arm would then transition vertically to begin printing the shell and the floors.

The outer shell is studded with windows that allow for a well-lit environment, the outer shell is separate from the core, and the shape of the structure is designed to ensure that dust storms flow around the structure. In fourth place was SEArch+/Apis Cor’s Mars X house, a habitat designed to provide maximum radiation protection while also ensuring natural light and connections to the Martian landscape.

The habitat is constructed by mobile robotic printers, which are deployed from a Hercules Single-Stage Reusable Lander. The design is inspired by Nordic architecture, and uses “light scoops” and floor-level viewing apertures to ensure that sunlight in the northern latitudes makes it into the interior. The two outer (and overlapping) shells house the living areas, which consist of two inflatable spaces with transparent CO2 inflated window pockets.

Fifth place went to the team from Northwestern University for their Martian 3Design habitat, which consists of an inner sphere closed-shell and an outer parabolic dome. According to the team, this habitat provides protection from the Martian elements through three design features. The first is the internal shape of the structure, which consists of a circular foundation, an inflatable pressure vessel that serves as the main living area, and the outer shell.

The second feature is the entryway system, which extend from opposite ends of the structure and serves as entrances and exits and could provide junctions with future pods. The third feature is the cross-beams that are the structural backbone of the dome and are optimized for pressure-loading under Martian gravity and atmospheric conditions, and provide continuous protection from radiation and the elements.

The interior layout is based on the NASA Hawai’i Space Exploration Analog and Simulation (HI-SEAS) habitat, and is divided between “wet areas” and “dry areas”. These areas are placed on opposite sides of the habitat to optimize the use of resources by concentrated in them on one side (rather than have them running throughout that habitat), and space is also divided by a central, retractable wall that separates the interior into public and private areas.

Together, these concepts embody the aims of the 3D-Printed Habitat Centennial Challenge, which is to harness the talents of citizen inventors to develop the technologies necessary to build sustainable shelters that will one-day allow humans to live on the Moon, Mars and beyond. As Lex Akers, dean of the Caterpillar College of Engineering and Technology at Bradley University, said of the competition:

“We are encouraging a wide range of people to come up with innovative designs for how they envision a habitat on Mars. The virtual levels allow teams from high schools, universities and businesses that might not have access to large 3D printers to still be a part of the competition because they can team up with those who do have access to such machinery for the final level of the competition.”

Carrying on in the tradition of the Centennial Prizes, NASA is seeking public engagement with this competition to promote interest in space exploration and address future challenges. It also seeks to leverage new technologies in order to solve the many engineering, technical and logistical problems presented by space travel. Someday, if and when human beings are living on the Moon, Mars, and other locations in the Solar System, the habitats they call home could very well be the work of students, citizen inventors and space enthusiasts.

For more information on the 3-D Pinrted Habitat Challenge, check out the competition web page.

Further Reading: NASA

New Photos of Saturn and Mars from Hubble

During the summer of 2018, the planets of Mars and Saturn (one after the other) have been in opposition. In astronomical terms, opposition refers to when a planet is on the opposite side of the Earth relative to the Sun. This not only means that the planet is closer to Earth in its respective orbit, but that is also fully lit by the Sun (as seen from Earth) and much more visible.

As a result, astronomers are able to observe these planets in greater detail. The Hubble Space Telescope took advantage of this situation to do what it has done best for the past twenty-eight years – capture some breathtaking images of both planets! Hubble made its observations of Saturn in June and Mars in July, and showed both planets close to their opposition.

Hubble’s high-resolution images of the planets and moons in our Solar System can only be surpassed by spacecraft that are either orbiting or conducting close flybys to them. However, Hubble has a major advantage over these types of missions, in that it can look at the Solar planets periodically and observe them over much longer periods of time than a passing spacecraft.

This composite image, taken by the NASA/ESA Hubble Space Telescope on June 6th, 2018, shows the ringed planet Saturn with six of its 62 known moons. Credit: NASA, ESA, A. Simon (GSFC) and the OPAL Team, and J. DePasquale (STScI)

Hubble observed Saturn on June 6th, almost a month before it reached opposition on June 27th. At the time, the ringed gas giant was approximately 1.4 billion km (870 million mi) from Earth. Hubble was able to capture the planet’s magnificent ring system at a time when it was at its maximum tilt to Earth, which allowed for a spectacular view of the rings and the gaps between them.

Hubble’s new image of Saturn also managed to capture the hexagonal storm around the gas giant’s north pole. This stable and persistent jet stream was first observed by the Voyager 1 probe during its flyby of Saturn in 1981, and has been a mystery to astronomers ever since. On top of that, the new image also features six of Saturn’s 62 known moons – Dione, Enceladus, Tethys, Janus, Epimetheus, and Mimas.

Hubble’s new image of Mars was captured on July 18th, 13 days before it reached its closest approach to Earth. This year will see the Red Planet get as close as 57.6 million km from Earth, which is the closest approach made since 2003. On that occasion, Mars was just 55,757,930 km (34,647,420 mi) from Earth, which was the closest the planet had been to Earth in almost 60,000 years!

Mars is at opposition to Earth every two years, so Hubble has had many opportunities to capture detailed images of the planet’s surface. However, this new image is different in that it is dominated by a gigantic sandstorm that is currently encompassing the entire planet. This storm has been raging since May of 2018 and developed into a planet-wide dust storm within several weeks.

In mid-July the NASA/ESA Hubble Space Telescope observed Mars, only 13 days before the planet made its closest approach to Earth in 2018. Credit: NASA, ESA, and STScI

Dust storms are a common occurrence on Mars. They take place every year, usually stay contained to a local area, and normally last only about a few weeks. Larger dust storms that can grow to cover the entire planet are a rarer event, and can typically last for weeks or even months. These tend to happen during the spring and summer months in the southern hemisphere, which coincides with Mars being closer to the Sun in its elliptical orbit.

Due to increased temperatures, dust particles are lifted higher into the atmosphere, creating more wind. The resulting wind kicks up yet more dust, creating a feedback loop that NASA scientists are still trying to understand. While spacecraft orbiting Mars and rovers and lander can study storm behavior at lower altitudes or from the surface, Hubble observations allow astronomers to study changes in the higher atmosphere.

The combined observations will help planetary scientists to better understanding how these global storms arise. Despite the obscuring dust storm, Hubble still managed to capture several important Martian surface features like the polar ice caps, Terra Meridiani, the Schiaparelli Crater, and Hellas Basin – even though all of them appear slightly blurred in the image.

The Hellas Basin – an impact basin that measures 2200 km (1367 mi) across and is nearly 8 km (4.97 mi) deep – is visible at the lower right and appears as a large and bright oval area. The orange area in the upper center of the image is Arabia Terra, a large upland area in northern Mars. This region is characterized by many impact craters and heavy erosion, which indicates that it could be among the oldest terrains on the planet.

This annotated image of Mars shows features of the planet that were visible in summer 2018 despite a global dust storm. Credit: NASA, ESA, and STScI

South of Arabia Terra are the dark streaks known as Sinus Sabaeus and Sinus Meridiani, features that stretch from east to west along the equator and are made of up dark bedrock and sand deposits from ancient lava flows. Because it was autumn in the northern hemisphere when the image was taken, it is covered in a bright blanket of clouds – and clouds can also be seen above the northern and southern polar ice caps. Last, but not least, Mars’ two small moons – Phobos and Deimos – appear in the lower half of the image.

Comparing these new images of Mars and Saturn with older data gathered by Hubble, other telescopes and the many probes that have taken images of them over the years will allow astronomers to study how cloud patterns and large-scale structures on the Solar planets change over time. These latest images also show that even after almost three decades of being in operation, Hubble is still able to pull its weight!

And be sure to enjoy this video about the images acquired by Hubble, courtesy of Hubblecast:

Further Reading: Hubble

Mars is 1000x Drier Than the Driest Places on Earth

For generations, many have dreamed about the day when it would be possible to set foot on Mars – aka. “Earth’s Twin” planet. And in the past few years, multiple orbiters, landers and rovers have revealed evidence of past water on Mars, not to mention the possibility that water still exists underground. These findings have fueled the desire to send crewed missions to Mars, not to mention proposals to establish a colony there.

However, this enthusiasm may seem a little misguided when you consider all the challenges the Martian environment presents. In addition to it being very cold and subject to a lot of radiation, the surface of Mars today is also extremely dry. According to a new study led by researchers from NASA’s Ames Research Center, Martian soil is roughly 1000 times drier than some of the driest regions on Earth.

The study, titled “Constraints on the Metabolic Activity of Microorganisms in Atacama Surface Soils Inferred from Refractory Biomarkers: Implications for Martian Habitability and Biomarker Detection, recently appeared in the journal Astrobiology. The study was led by members from NASA Ames Research Center and included researchers from the Georgia Institute of Technology, the Carl Sagan Center at the SETI Institute, the Centro de Astrobiologia (INTA-CSIC), the NASA Goddard Space Flight Center, and the Massachusetts Institute of Technology.

The Atacama Desert in northern Chile. Credit: NASA/Frank Tavares

For the sake of their study, the research team sought to determine if microorganisms can survive under the types of conditions present on Mars. To answer this question, the team traveled to the the Atacama Desert in Chile, a 1000 km (620 mi) strip of land on South America’s west coast. With an average rainfall of just 1 to 3 mm (0.04 to 0.12 in) a year, the Atacama desert is known as the driest nonpolar place in the world.

However, the Atacama desert is not uniformly dry, and experiences different levels of precipitation depending on the latitude. From the southern end to the northern end, annual precipitation shifts from a few millimeters of rain per year to only a few millimeters of rain per decade. This environment provides an opportunity to search for life at decreasing levels of precipitation, thus allowing researchers to place constraints on microorganism survivability.

It is at the northern end of the desert (in what is known as the Antofagasta region) where conditions become most Mars-like. Here, the average annual rainfall is just 1 mm a year, which has made it a popular destination for scientists looking to simulate a Martian environment. In addition to seeing if microbes could survive in these dry conditions, the team also sought to determine if they were capable of growth and reproduction.

As Mary Beth Wilhelm – an astrobiologist at the Georgia Institute of Technology, NASA’s Ames Research Center, and lead author of the new study – explained in a recent NASA press release:

“On Earth, we find evidence of microbial life everywhere. However, in extreme environments, it’s important to know whether a microbe is dormant and just barely surviving, or really alive and well… By learning if and how microbes stay alive in extremely dry regions on Earth, we hope to better understand if Mars once had microbial life and whether it could have survived until today.”

Researchers collect samples from the surface of the Atacama Desert in Chile, going a few centimeters into the ground. Credits: NASA Ames Research Center

After collecting soil samples from across the Atacama Desert and brought them back to their lab at Ames, the research team began performing tests to see if their microorganism samples showed any indication of stress markers. These are a key way in which life can be shown to be growing, since organisms in a dormant state (i.e. that are just surviving) show no signs of stress markers.

Specifically, they looked for changes in the lipid structure of the cells outer membranes, which typically become more rigid in response to stress. What they found was that in the less dry parts of the Atacama Desert, this stress marker was present; but strangely, these same markers were missing in the driest regions of the desert where microbes would be more stressed.

Based on these and other results, the team concluded that there is a transition line for microorganisms in environments like the Atacama Desert. On one side of this line, the presence of minute amounts of water is enough for organisms to still be able to grow. On the other side, the environment is so dry that organisms can survive but will not grow and reproduce.

The team was also able to find evidence of microbes that had been dead in the Atacama soil samples for at least 10,000 years. They were able to determine this by examining the amino acids of the microbes, which are the building blocks of proteins, and examining the rate at which their structure changed. This find was rather surprising, seeing as how it is extremely rare that the remnant of ancient life be found on the surface of Earth.

This artist’s concept depicts NASA’s Mars 2020 rover exploring Mars. Credit: NASA

Given that Mars is 1,000 times drier than even the driest parts of Atacama, these results were not encouraging news for those hoping that microbial life will still be found there. However, the fact that the remnants of past microbial life were found in the driest areas of Chile’s desert – which would have existed when conditions were wetter and were well-preserved – is very good news when it comes to the search for past life on Mars.

Essentially, if microbial life did exist on Mars back when it was a warmer, wetter environment, traces of that ancient life might still exist. As Wilhelm explained:

“Before we go to Mars, we can use the Atacama like a natural laboratory and, based on our results, adjust our expectations for what we might find when we get there. Knowing the surface of Mars today might be too dry for life to grow, but that traces of microbes can last for thousands of years helps us design better instruments to not only search for life on and under the planet’s surface, but to try and unlock the secrets of its distant past.”

In the future, missions like NASA’s Mars 2020 rover will be seeking to procure samples of Martian soil. If NASA’s proposed “Journey to Mars” takes place by the 2030s as planned, these samples could then be returned to Earth for analysis. With luck, these soil samples will reveal evidence of past life and prove that Mars was once a habitable planet!

Further Reading: NASA

Underground Liquid Water Found on Mars!

According to evidence gathered by multiple robotic orbiters, rovers, and landers over the course of several decades, scientists understand that Mars was once a warmer, watery place. But between 4.2 and 3.7 billion years ago, this began to change. As Mars magnetic field disappeared, the atmosphere slowly began to be stripped away by solar wind, leaving the surface the cold and dry and making it impossible for water to exist in liquid form.

While much of the planet’s water is now concentrated in the polar ice caps, scientists have speculated some of Mars’ past water could still be located underground. Thanks to a new study by a team of Italian scientists, it has now been confirmed that liquid water still exists beneath Mars’ southern polar region. This discovery has put an end to a fifteen-year mystery and bolstered the potential for future missions to Mars.

The study, titled “Radar evidence of subglacial liquid water on Mars“, recently appeared in the journal Science. The study was led by Roberto Orosei of the National Institute of Astrophysics (INAF) in Italy, and included members from the Italian Space Agency (ASI), the ESA Center for Earth Observation (ESRIN), and multiple observatories, research institutions and universities.

Radar detection of water under the south pole of Mars. Credit: ESA/NASA/JPL/ASI/Univ. Rome

So far, robotic missions have revealed considerable evidence of past water on Mars. These include dried-out river valleys and gigantic outflow channels discovered by orbiters, and evidence of mineral-rich soils that can only form in the presence of liquid water by rovers and landers. Early evidence from the ESA’s Mars Express probe has also showed that water-ice exists at the planet’s poles and is buried in the layers interspersed with dust.

However, scientists have long suspected that liquid water could exist beneath the polar ice caps, much in the same way that liquid water is believed to underlie glaciers here on Earth. In addition, the presence of salts on Mars could further reduce the melting point of subsurface water and keep it in a liquid state, despite the sub-zero temperatures present on both the surface and underground.

For many years, data from the Mars Express’ Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) instrument – which has been used to study the southern polar region – has remained inconclusive. Like all ground-penetrating radar, this instrument relies on radar pulses to map surface topography and determine the properties of the materials that lie beneath the surface.

Luckily, after considerable analysis, the study team was able to develop new techniques that allowed them to collect enough high-resolution data to confirm the presence of liquid water beneath the southern ice cap. As Andrea Cicchetti, the MARSIS operations manager and a co-author on the new paper, indicated:

“We’d seen hints of interesting subsurface features for years but we couldn’t reproduce the result from orbit to orbit, because the sampling rates and resolution of our data was previously too low. We had to come up with a new operating mode to bypass some onboard processing and trigger a higher sampling rate and thus improve the resolution of the footprint of our dataset: now we see things that simply were not possible before.”

Water detection under the south pole of Mars. Credit: Context map: NASA/Viking; THEMIS background: NASA/JPL-Caltech/Arizona State University; MARSIS data: ESA/NASA/JPL/ASI/Univ. Rome; R. Orosei et al 2018

What they found was that the southern polar region is made of many layers of ice and dust down to a depth of about 1.5 km over a 200 km-wide area, and featured an anomalous area measuring 20-km wide. As Roberto Orosei, the principal investigator of the MARSIS experiment and lead author of the paper, explained in a recent ESA press release:

“This subsurface anomaly on Mars has radar properties matching water or water-rich sediments. This is just one small study area; it is an exciting prospect to think there could be more of these underground pockets of water elsewhere, yet to be discovered.”

After analyzing the properties of the reflected radar signals and taking into account the composition of the layered deposits and expected temperature profiles below the surface, the scientists concluded that the 20-km wide feature is an interface between the ice and a stable body of liquid water. For MARSIS to be able to detect such a patch of water, it would need to be at least several tens of centimeters thick.

These findings also raise the possibility of there being life on Mars, both now and in the past. This is based on research that found microbial life in Lake Vostok, which is located some 4 km (2.5 mi) below the ice in Antarctica. If life can thrive in salty, subglacial environments on Earth, then it is possible that they could survive on Mars as well. Determining if this is the case will be the purpose of existing and future missions to Mars.

The MARSIS instrument on the Mars Express is a ground penetrating radar sounder used to look for subsurface water and ice. Credit: ESA

As Dmitri Titov, one of the Mars Express project scientist, explained:

“The long duration of Mars Express, and the exhausting effort made by the radar team to overcome many analytical challenges, enabled this much-awaited result, demonstrating that the mission and its payload still have a great science potential. This thrilling discovery is a highlight for planetary science and will contribute to our understanding of the evolution of Mars, the history of water on our neighbour planet and its habitability.”

The Mars Express launched on June 2nd, 2003, and will celebrate 15 years in orbit of Mars by December 25th this year. In the coming years, it will be joined by the ESA’s ExoMars 2020 mission, NASA’s Mars 2020 Rover, and a number of other scientific experiments. These missions will pave the way for a potential crewed mission, which NASA is planning to mount by the 2030s.

If there is indeed liquid water to be found on Mars, it will go a long way towards facilitating future research and even an ongoing human presence on the surface. And if there is still life on Mars, the careful research of its ecosystems will help address the all-important question of how and when life emerged in the Solar System.

Further Reading: ESA, Science