Category: Mars

New research into the interior of Mars further emphasizes that the Red Planet is a world of two very different halves.

Deep inside the southern hemisphere of Mars, the temperature is up to 750 degrees Fahrenheit (400 degrees Celsius) warmer than beneath the northern hemisphere, deepening the mystery of the strange dichotomy between the Red Planet's flattened north and craggy southern highlands.

"Scientists usually assume that the interiors of planetary bodies are generally spherically symmetric, but this is not necessarily true," said Alexander Berne, formerly of Caltech and now at the University of Arizona, in a statement. Berne is the lead author of a new research paper revealing the discovery of the strange southern hotspot.

Berne and his team went back and looked at archival data from three NASA spacecraft – Mars Global Surveyor, Mars Odyssey and Mars Reconnaissance Orbiter – to look for subtle changes in their orbital velocity that might reflect variations in Mars's gravitational field. Using a technique developed by Berne called 'tidal tomography' that also accounts for the sun's varying gravitational influence on Mars as the Red Planet progresses around its elliptical orbit, he and his team were able to infer a model of the interior structure and temperature of Mars.

How the gravitational field that the various spacecraft experienced changed over time differs substantially from what would be expected were Mars's interior perfectly spherically symmetrical. To explain this difference, the mantle beneath Mars's southern hemisphere must be between 390 and 750 degrees Fahrenheit (200 and 400 degrees Celsius) warmer than the mantle in the north, and indeed it is so warm that it could still be partially molten. This could have repercussions for both Mars's habitability and how long Mars remained volcanically active.

Perhaps we shouldn't be surprised that Mars's interior is different in the south compared to the north, because we already know that its surface is asymmetrical. The north of Mars is characterized by lowland plains, while the planet's crust in the south is on average 15.5 miles (25 kilometers) thicker than in the north and is covered by cratered highlands. The northern lowlands may have once been home to a large ocean.

"The dichotomy that we see between north and south is important to understand because it gives information about processes that may have influenced the hydrology of Mars, including the formation of basins that may have held water," said Caltech's Amirhossein Bagheri, who is the second author of the research.

A hotter southern mantle could also explain some other puzzling discoveries on Mars. NASA's InSight lander, which ended its mission in December 2022 and which had a seismometer on board, found that seismic waves dissipate more quickly in the south, which can be explained by the hotter temperature there. Additionally, magnetic anomalies found in iron-bearing minerals in the south now make more sense.

Today, Mars lacks a global magnetic field, but over four billion years ago it had one. If upwelling from a warmer southern mantle heated the crust in excess of the 'Curie temperature', which is the temperature at which materials lose their inherent magnetic properties and any residual magnetism in them is induced, it could have resulted in creating the mysterious magnetic remnants in the iron-bearing minerals.

"Understanding the interior structure of planetary bodies helps us unravel the processes that shaped their formation and evolution," said Berne, although the origin of Mars's north–south divide is still up in the air. It's not even clear whether the surface differences have the same causes as the interior differences.

The leading contender is that it's all the result of an ancient giant impact over four billion years ago and that the northern lowlands are therefore actually an enormous impact basin. By gouging out a huge hole in the north, the impact would have facilitated the release of a lot of internal heat, allowing the northern mantle to cool faster than the south.

Alternatively, the thicker crust in the south could have proven to be an efficient lid, preventing the leaking of much heat from the mantle. This can actually be tested – magma upwelling would have stalled as it encountered the thick, dense crust, creating melt intrusions beneath the surface that could be inferred in higher-resolution gravity data.

These are questions for future missions, but the tidal tomography technique could be employed for other worlds too, from Mercury to the large moons of Jupiter.

"As we get more gravity data, we can determine the three-dimensional intricacies of a planet's interior structure," said Berne. "These inferences in turn give us a blueprint for designing future missions and scientific exploration of these worlds."

The discovery of Mars's thermal anomaly was reported on Aug. 27 in Nature.

The world just got its first good looks at some hardware that will make spaceflight history.

Last Thursday (Aug. 13), Japan unveiled the spacecraft that make up its Martian Moons eXploration (MMX) mission, which aims to snag samples of the Mars moon Phobos and haul them to Earth — something that has never been done.

The big reveal came at Tanegashima Space Center, the site from which MMX will launch toward the Red Planet atop an H3 rocket. And we just got some clarity about when that liftoff will take place.

If all goes according to plan, MMX will launch on Oct. 19 at 3:41 p.m. EDT (1941 GMT; 4:41 a.m. on Oct. 20 Japan time), the Japan Aerospace Exploration Agency (JAXA) announced on Thursday (Aug. 20). That's the first day of the mission's launch window, which extends through Nov. 7.

JAXA originally intended to launch MMX in 2024 but had to stand down due to issues with the H3. Mars and Earth align properly for interplanetary launches just once every 26 months, so this was a significant delay.

MMX will spend about a year traveling to Mars. Once in orbit around the Red Planet, the mission will map and study its two small moons, Phobos and Deimos, which are just 14 miles (22 kilometers) and 7.5 miles (12 km) wide, respectively.

Part of this work will help the mission team pick a landing site on Phobos, where they'll drop a 55-pound (25 kilograms) French-German rover called Idefix. That little robot — which is named after the dog in the French comic "Asterix" — will study Phobos' surface in detail using a variety of instruments.

The MMX spacecraft itself will then spiral down toward Phobos, eventually making contact and collecting about 0.35 ounces (10 grams) of material. MMX will leave Mars orbit with these samples in 2030 and deliver them to Earth for analysis a year later.

The mission aims to shed light on the nature and origin of Phobos and Deimos.

"Understanding how Mars and the two moons formed is a heavily debated topic in solar system science," JAXA officials wrote in a mission description.

"Remote-sensing observations by the MMX spacecraft and the detailed analyses of the returned sample will determine whether Phobos and Deimos are remnants of early Mars created from debris produced by a giant impact with the young planet, or whether the moons are asteroids captured by Mars's gravity that brought material from outer solar system," they added.

To date, no spacecraft has returned material from the Mars system. Russia tried to do so with its Phobos-Grunt mission, which aimed to sample the eponymous Red Planet moon, but that effort failed shortly after its November 2011 launch. (The Soviet Union also launched two probes to Phobos in 1988, but neither one of them met its mission objectives.)

NASA plans to collect and haul home pristine samples that have already been collected on the Martian surface by its Perseverance rover, but it's unclear when or if that will happen. The agency has deemed its original sample-return architecture too expensive and is currently investigating other options.

There are good reasons to believe that Japan will succeed where others have failed, however. The country has a history of small-body sample-return success; its Hayabusa mission brought home pieces of the asteroid Itokawa in June 2010, and Hayabusa2 did the same with material from the space rock Ryugu in December 2020.

Europe's Mars Express orbiter has captured new, stunning imagery flying low over a geological region of the Red Planet shaped by ancient waterflow billions of years ago.

Mars Express launched in 2003 and is operated by the European Space Agency (ESA). It's equipped with the High Resolution Stereo Camera, which scans multiple points of perspective across regions of Mars' surface to create 3D color renderings. During a low pass on the spacecraft's highly elliptical orbit, Mars Express flew over the planet's Southern Highlands and Schiaparelli Crater — one of Mars' largest impact sites.

Schiaparelli Crater is located in a heavily cratered region of Mars' Southern Highlands, where a wetter and warmer climate supported water flows that shaped the planet's geography 3.7 billion years ago, according to ESA's Mars Express video. Schiaparelli measures more than 285 miles (460 km) across, and has a bit of fictional fame. The crater happens to be the site where astronaut character Mark Watney gets stranded in Andy Weir's "The Martian". It also shares a namesake with ESA's real-life Schiaparelli Mars lander, which crashed on Mars' surface in 2016 (but wasn't headed for Schiaparelli Crater).

Both are named for Italian astronomer Giovanni Schiaparelli (1835–1910), who made detailed observations of Mars during the planet's closest approach in 1877. Schiaparelli created a map of "canali," Italian for "channels," he saw as dark lines across its surface, which he assumed were filled with water. That was later mistranslated by English-speaking astronomers as "canals," leading to speculation about intelligent life on Mars constructing artificial structures.

Though that hypothesis for Mars' surface features was disproven by later astronomers (to date, there have been no discoveries on Mars that suggest intelligent life once lived there), it has since been discovered that Mars once did have active bodies of water on its surface. Schiarapelli's contributions to the astronomical field were significant enough to land him the honor of a Martian crater in his name.

Despite its massive diameter, Schiaparelli is considered shallow compared to other Martian craters its size. It was once much deeper, but sediment deposited by wind and ancient water flows, volcanic eruptions and asteroid impact debris have filled the crater over the last several billion years.

In addition to showcasing Mars Express' new footage, the ESA video also provides an explanation for how the satellite uses its High Resolution Stereo Camera to observe five simultaneous viewing angles over a four-color spectrum as it flies low over the planet. The low-orbit passes allow Mars Express to capture swaths of 3D data that span hundreds to thousands of miles long and dozens of miles across. Those are then stitched together to form more complete regional maps, which can be added to scientists' increasingly complex model of the entire Martian globe.

People around the world enjoyed stellar views with last week's total solar eclipse.

And the day after we looked up to see the moon obscuring out sun, NASA's Perseverance Mars rover looked up to see its own Martian solar eclipse.

What is it?

Solar eclipses aren't unique to Earth. In theory, any planet with at least one orbiting moon would have times where that moon might eclipse some part of its sun to anyone looking up from the planet's surface.

On Aug. 13, 2026, one day after Earth's total solar eclipse in which our moon temporarily blocked out our sun for skywatchers in some locations, Mars saw its own solar eclipse.

Looking up with its left Mastcam-Z camera, Perseverance snapped this image of one of Mars' two moons, Phobos and Deimos, partially eclipsing the sun. This appears to be Phobos — the larger of the pair — eclipsing the sun.

Why is it incredible?

So far, we humans have only directly had vantage points on Earth, in Earth orbit and on the moon. We have not yet landed humans on Mars, and it remains unclear how long it might be before that happens.

But robotic explorers like Perseverance allow us to travel where we can't go ourselves. Such travelers have taken us into interstellar space and all throughout our solar system. From Saturn's rings to Neptune's distant, icy neighborhood, robotic probes have allowed humanity's reach to stretch far through the cosmos.

And thanks to Perseverance and its two "eyes," the two Mastcam-Z cameras located high on its mast, we can travel right to the surface of Mars, look up and see an alien solar eclipse. What an amazing thing that is.

On Aug. 17, 1877, American astronomer Asaph Hall discovered Mars's moon Phobos.

Moons of Mars: Amazing Photos of Phobos and Deimos

Hall was working at the U.S. Naval Observatory in Washington, D.C. and looking through a 26-inch refractor telescope — which was then the largest in the world — when he first spotted the moon. Six days earlier, he had discovered another, smaller moon that he first described as "a faint star near Mars."

Upon further inspection, not only did he realize that this star was actually the Martian moon Deimos, but he also discovered a second, larger moon now known as Phobos. He announced both discoveries the following day, on Aug. 18, 1877.

Phobos is the largest moon of Mars. Its dimensions measure 10 by 14 by 11 miles (17 by 22 by 18 kilometers) across and orbits Mars three times each Martian day at a distance of about 3,700 miles (6,000 km).

Why it mattered

Over the century and a half since this discovery, there has been an enormous amount of scientific progress in the study of Mars. In addition to many decades of studying the planet from afar, we have seen a variety of different orbiters and rovers explore the Red Planet over the past few decades. We have sampled bits of Martian material, seen up-close photos of the planet and the rocks which scatter across its surface. It might be easy to take for granted how much we know about our planetary neighbor, and this 19th century discovery was groundbreaking.

As we look to the future with new technologies and new discoveries on the horizon, it is important to also look backward to see and understand the history and work that made all of this progress possible.

A newly found Mars meteorite is revealing the secrets of a previously hidden time period of Red Planet geological history.

The 1.27-billion-year-old space rock, called Northwest Africa (NWA) 13441, was discovered in Algeria in 2019 — but its age was not confirmed until recently. Now scientists say the meteorite helps answer questions about a huge gap in the Martian geologic record: a span of time between 600 million years ago and 2.4 billion years ago.

This vast timespan has no known examples of meteorites containing igneous (solid magma) shergottites, which are the most abundant type of Martian meteorites, chunks of the Red Planet that were blasted away by impacts, ejected into space and eventually fell to Earth. The only meteorites known from this time range, roughly 1.3 billion to 1.4 billion years ago, are rarer types known as chassignites and nahklites. As such, the newly analyzed meteorite is opening new insights already about this time period.

"The characteristics of this meteorite were entirely surprising," stated Boston College Earth and environmental sciences professor Ethan Baxter, co-author of a study published Aug. 1 in the journal Geochimica et Cosmochimica Acta. "No other Martian meteorite like this has an age of 1.27 billion years old."

NWA 13441 was surprising to researchers in two ways. The first was its composition — while it is a shergottite, the space rock also contains isotopes (element types) of a rare-Earth metal called neodymium. Neodymium is usually found in chrondrites — another kind of meteorite made up of unmelted rocks — and chondrites were common in the solar system when it was formed 4.56 billion years ago.

This blended composition of shergottite and chrondrite suggests deeper parts of Mars have remained relatively untouched since the planet was formed, Baxter stated. That finding aligns with what scientists already know about Mars, which likely formed only five million years after the solar system was formed. (Mars also has no plate tectonics, making it different from Earth and which allows the earliest bits of it to remain undisturbed by the types of geologic processes that take place on our planet.)

Peering deeper at the chondrites added a second surprise: the composition of the isotopes, or element types, are helping establish "new boundaries on the processes that happened in the very early solar system as Mars formed," the authors stated. The paper's abstract added this information suggests the meteorite may have come from a "previously unsampled" reservoir on the Red Planet lying between "enriched and depleted shergottite sources."

Scientists hope that more analysis of this meteorite will reveal "magmatic and volcanic activity on Mars," Seal said in the same statement. Next up will be looking at the meteorite's isotopes to figure out its connection to other meteorites formed early in Martian history.

Picture it: A swarm of tiny robot helicopters descends through a reddish-brown sky, landing gracefully on the Martian surface. What are they wearing? Tiny capes.

NASA's SkyFall mission will send a trio of mini rotorcraft to Mars equipped with ground penetrating radar technology which happens to look like little capes. These uniquely designed swaths of fabric look decidedly strange or even accidental in new videos from NASA's Jet Propulsion Laboratory (JPL) that show the little drones practice landing. But these capes are actually flexible antennae that will allow the craft to peer beneath the Red Planet's surface in search of water ice.

"The only way to detect shallow subsurface ice remotely is to fly close to the ground," Adrian Tang, SkyFall’s ground-penetrating radar lead instrument scientist at JPL, said in a statement on Thursday (Aug. 6). "By flying low and slow, a SkyFall helicopter could capture radar images that resolve the fine layering where dry soil gives way to ice, detecting its presence and mapping its extent."

Orbiting spacecraft have studied Mars for decades, imaging the planet and mapping it with radar. But from orbit, their radar is unable to see the first few feet of material just below the planet's surface — a zone where scientists expect to find shallow ice deposits mixed in with the rocks and dust. This work could be important for future astronauts who need to better understand the ground below their feet for safety reasons, and for future travelers searching for accessible ice to process for drinking water, oxygen and fuel.

Skyfall will follow in the footsteps of Ingenuity, the first rotorcraft on another world, which hitched a ride to Mars aboard NASA's Perseverance rover. The new choppers are based heavily on Ingenuity, which weighed just 4 pounds (1.8 kilograms) here on Earth. But Skyfall will be more capable than Ingenuity, whose main job was to show that choppers can explore the thin skies of Mars.

SkyFall's tiny cape ground-penetrating radar, which uses a type of flexible antenna called Vivaldi that was invented back in 1978, is designed to survey up to 16 feet (5 meters) below the Martian surface. The radar will be able to reach anywhere from several yards below the planet's surface to the uppermost layers of surface material.

And the antenna's unique design ensures that the SkyFall drones will be able to make these subsurface observations without damaging the equipment during landing.. The antenna is extremely lightweight, and the team miniaturized it to be both the right size and shape to fit the tiny helicopters, which sit just 6 inches (15 centimeters) above the ground at rest. The tricky thing was, the designers had to miniaturize the radar antennae while maintaining functionality. But they did just that, and these tiny radar capes will be able to bend and move out of the way as the rotorcraft do their thing, flying above and landing on the Red Planet.

"Although we managed to shrink the antenna quite a bit, it is about 1.5 times longer than the helicopter’s legs," Christine Gebara, SkyFall ground-penetrating radar mechanical lead at JPL, added in the statement.

"That means during landing, the Vivaldi has to bend out of the way — and if it lands on a rock, it bends even further," she added. "But when the helicopter takes off again, the antenna must spring back into place for data collection. Because SkyFall is expected to make dozens of flights exploring Mars, we needed an antenna that could repeatedly handle those pressures without losing its shape in flight."

To make these little capes capable of withstanding incredible feats on another world, the engineers behind the helicopters covered the antenna in layers of polyester and Vectran, a flexible (but incredibly strong) material that was previously used for the airbag that cushioned NASA's Spirit and Opportunity Mars rovers during their touchdowns in 2004. The antenna's shape is also reinforced with flexible fiberglass tape springs and a lightweight structure. In total, each antenna weighs a miniscule 5 ounces (142 grams).

But a crafty design isn't enough. Getting to Mars is no small feat, and NASA needs to be sure that these little helicopters and their gear are up to the challenge. So, in JPL's Environmental Test Laboratory, which recreates different elements of environments beyond Earth, the SkyFall team put the rotorcraft and its little radar antenna to the test. They bent and flexed the antenna over and over, recreating multiple landings on the surface, exposed the craft to extreme temperatures, and continually checked to make sure that, throughout this testing, the helicopter could still transmit and receive radar signals. At the end of this testing, the antenna had endured 200 simulated Mars landings and was still working just fine. That is more than twice the number of landings expected from the mission.

"This test checked every box it was supposed to and answered our biggest technical questions," Tang added. "While we still have work ahead of us before the antenna is fully flight-qualified, this was a major milestone, and the hardware performed exactly as expected."

The trio of SkyFall helicopters will put their radar capes to the ultimate test when they fly to Mars. NASA plans to launch this mission to the Red Planet in 2028 aboard NASA's Space Reactor-1 Freedom, the first nuclear fission-powered interplanetary spacecraft.

NASA's Curiosity Mars rover spotted surprising shapes in the Red Planet soil while exploring a large valley.

What is it?

These images were captured on June 19 and 20, 2026, or the 4,930th and 4,931st Martian days of Curiosity's mission. They show honeycomb-like patterns referred to as "polygonal fractures" found in a valley on Mars known as Valle Grande. They measure about 1.5 to 3 inches (4 to 8 centimeters) across.

While Curiosity has seen other curious geometric patterns on Mars before, scientists were surprised by this most recent find.

"We've seen a lot of fascinating landscapes through Curiosity's eyes, but this sea of polygons took our breath away," project scientist Ashwin Vasavada of NASA's Jet Propulsion Laboratory said in a statement. "We measured their shapes and chemistry carefully and are hopeful there are clues in the data as to how these features formed."

Why is it incredible?

This field of polygons in Valle Grande extends as far as Curiosity's instruments could see, even around the base of a steep hill scientists named "Miraflores."

While mission scientists have theories about how these structures form, it ultimately remains a mystery how they formed.

It's thought that changes in temperatures on Mars could have caused water to squeeze through sediment layers, but scientists will need to collect more data before they can reach a conclusive answer.

Planting boots on Mars is hard enough. But getting "breathing room" on the Red Planet without inhaling toxic dust is yet another issue.

Given NASA's plans to eventually put astronauts on the Red Planet, the agency assembled a Martian Dust Limit Working Group earlier this year to review what's known and unknown about the toxicological hazard to human crews from exposure to Mars dust. The ultimate goal was to establish a permissible exposure limit for humans on the Red Planet by compiling a comprehensive set of expert perspectives regarding Martian dust toxicology, exposure pathways and mitigation strategies.

The working group's conclusions reinforced the view that an initial Martian dust standard "must balance conservatism with operational feasibility while accommodating architectural and scientific uncertainty," the report states. Furthermore, the report explains, "as additional Martian data and toxicological research become available, this standard should be periodically revisited to ensure continued protection of crew health during human exploration of Mars."

Unique study

A panel member for that study was Brian Hynek professor in the Department of Earth Science and a research associate at the Laboratory for Atmospheric and Space Physics, both at the University of Colorado, Boulder.

"It was a unique study," Hynek told Space.com, conducted by NASA specialists, space medicine experts, habitat designers, including toxicologists, volcanologists and geologists. "The task was to help gauge health hazards to humans, both for short and long-term stays," he said.

Just highlighting the differences between the moon and Mars played a role, said Hynek. "The moon is worse in some ways and Mars is worse in other ways."

Disneyland of dust

To be sure, one outcome from Apollo moonwalkers – the "dusty dozen" – is that dealing with lunar dust proved to be troublesome, much more than expected. The aged moon is a Disneyland of dust and crews that went there attested to that fact.

Once out and about, moonwalkers coped with very fine, tiny particles composed of sharp, glassy material. Lunar dust stuck to everything it came in contact with; dust eroded their spacesuits, caused overheating on equipment and instrumentation, compromised seals on their spacesuits, even irritated the eyes and lungs of moonwalkers.

"On Mars, dust particles are a little more rounded, not as jagged and cutting into you. But then you have all the extra chemical components and minerals that you don't have on the moon, like really unhealthy perchlorates," Hynek said. "We can use the lunar knowledge, but Mars is a totally different place," he added.

Heavy metals

Hynek noted that Martian dust is known to contain various carcinogens, such as silica and numerous heavy metals. He co-authored a recent paper on "Potential Health Impacts, Treatments, and Countermeasures of Martian Dust on Future Human Space Exploration."

"There's talk about growing crops on Mars," Hynek observed. "The martian soil is full of all these nasty chemicals. So the astronauts might get more exposure from what they are growing on Mars than the actual airborne dust," said Hynek.

Then there's the dust that will assuredly find its way into the habitat, Hynek said, so engineers are looking at filtering systems and just how much time will be required to clean the inside of the habitat.

"It's good to have the forethought and to start considering the Martian dust and its hazards. It poses a lot more health hazards than the lunar dust," Hynek concluded.

Learned our lesson

Joel Levine, a research professor in applied science at William and Mary in Williamsburg, Virginia, is a leading expert on lunar dust, engineering and safety concerns. He was not a panel member of the NASA report.

Levine cited earlier thinking from a recent National Academy of Sciences report on human exploration of Mars. Two goals noted in that 2026 report are Mars dust-related:

• Determine what controls the onset and evolution of major dust storms, which dominate present-day atmospheric variability.
• Characterize the effects of Martian dust on human physiology and hardware lifetime.

"This indicates that Mars dust is on the minds of mission planners! This is good news based on our experience with lunar dust on the Apollo landings," said Levine. "It looks like we learned our lesson about dust at future human landing sites."

Levine stated that Mars sample returns would be very helpful to characterize Martian dust samples for chemical composition and other qualities. "Unfortunately, it does not look like the Mars samples already collected will ever be returned to the Earth for analysis," he said.

Major takeaways

Shaunna Morrison, an associate professor in the Department of Earth and Planetary Sciences at Rutgers University in New Jersey, served as a panel member on the Martian Dust Limit Working Group.

"One of the major takeaways from the Mars dust working group is that martian dust is a real crew-health and engineering issue, but it is also a tractable one if it is treated as a design requirement from the beginning," Morrison emphasized.

The worry is not that Mars dust is uniquely or catastrophically toxic based on what we know now, Morrison told Space.com.

"The concern is that future crews will be living and working in a closed habitat, repeatedly going outside, bringing dust back in on suits and equipment, in a low-humidity environment," said Morrison. That's a condition in which small particles are more prone to becoming airborne and potentially inhaled, she said, and potentially crew members being exposed to fine respirable particles over many days.

Prevention first

Morrison said that a key point is that we do not have as yet returned samples of authentic airborne martian dust. So NASA has to build a conservative standard using the best available evidence: lunar dust toxicology, Mars simulant studies, and the very extensive chemical and mineralogical datasets from Mars rovers and landers, she pointed out.

"The best strategy is prevention first," Morrison said. "Keep as much dust as possible outside the habitat, remove it quickly when it gets in, monitor airborne particles, and design the system so crews are not relying on medical countermeasures after exposure," she advised.

More than 20 years after NASA's Spirit rover began exploring Mars, scientists have uncovered a hidden clue in its archival data that adds to mounting evidence that the Red Planet was once rich in liquid water.

Researchers reanalyzed measurements collected by Spirit between 2004 and 2010, revealing widespread traces of crystalline hematite and altered magnetite in ordinary Martian soil — iron-bearing minerals that point to ancient chemical changes consistent with interactions between water and rock. The findings suggest liquid water may have been more widespread across Mars than scientists previously thought, according to a statement from Edith Cowan University (ECU) in Australia.

The team combined hundreds of individual measurements from 32 undisturbed soil sites inside Gusev Crater, where Spirit landed in January 2004, creating the most detailed iron-mineral profile yet assembled for typical Martian soil, according to the statement.

"One of the most important discoveries was finding crystalline hematite in ordinary Martian soil," Paulo de Souza, lead author of the study and an ECU professor, said in the statement. "This mineral's widespread presence suggests not only that water was present, but that significant areas of Mars may have once been covered by water."

Crystalline hematite has long been considered one of the strongest mineral indicators of past water on Mars. While it can also form through volcanic or hydrothermal activity, it commonly develops when iron-bearing rocks interact with liquid water.

The discovery is particularly significant because previous analyses concluded that crystalline hematite was largely absent from Spirit's landing site. According to the researchers, the mineral's signature was simply too faint to stand out in individual rover measurements. By combining thousands of spectra collected over the mission, however, the team was able to tease the signal out of the background noise.

The researchers also identified altered magnetite, suggesting the original volcanic minerals in the Martian soil were chemically transformed over time. Together, the altered magnetite and crystalline hematite provide new evidence that water played an important role in reshaping the planet's surface. And, because similar dust and soil blanket much of Mars, the findings could have implications well beyond Gusev Crater, suggesting water-related chemical processes may have been more widespread across the planet than previously believed.

The results add to a growing body of evidence that Mars was once far more habitable than it is today. During its mission, Spirit discovered water-altered rocks and minerals in the Columbia Hills, while NASA's Curiosity rover later found evidence that Gale Crater once hosted long-lived lakes. More recently, Perseverance has been exploring the remnants of an ancient river delta inside Jezero Crater, where scientists hope to determine whether the environment could once have supported microbial life.

Beyond revealing another chapter of Mars' watery past, the research also highlights the lasting scientific value of spacecraft data long after a mission has ended.

"This work shows that important discoveries are not always made by collecting new data," de Souza said in the statement. "Sometimes they come from looking at existing data with fresh eyes and better analytical techniques."

Their findings were published June 26 in the journal Interactions.