BY:SpaceEyeNews.
Long-lasting habitability on Mars changes the story
For years, Mars science followed a simple script. The Red Planet started out warmer and wetter, with rivers, lakes and even a global ocean. Then it lost its atmosphere, its water escaped, and habitability ended early. A new study using NASA’s Curiosity rover data now argues that this script is far too short. Instead, long-lasting habitability on Mars may have stretched on for billions of years below the surface, long after the oceans faded from view. dailygalaxy.com
Researchers at New York University Abu Dhabi (NYUAD), led by astrophysicist Dimitra Atri, dug into one of Curiosity’s most intriguing targets inside Gale Crater: ancient sand dunes that turned into rock. Their analysis, published in Journal of Geophysical Research: Planets, suggests that groundwater continued to flow through these dunes long after Mars’ climate collapsed at the surface. dailygalaxy.com
At the same time, NASA faces a serious debate about whether to cancel or drastically reshape its flagship Mars Sample Return (MSR) program. That mission is designed to bring rocks collected by the Perseverance rover back to Earth. According to a recent report in Scientific American, billions of dollars have already been spent, yet U.S. officials are now openly considering abandoning the retrieval plan. Scientific American
The irony is striking. Just as evidence for long-lasting habitability on Mars becomes stronger, the political support for returning its most precious samples is under threat.
This animation depicts water disappearing over time in the Martian river valley Neretva Vallis, where NASA’s Perseverance Mars takes the rock sample named “Sapphire Canyon” from a rock called “Cheyava Falls,” which was found in the “Bright Angel” formation. Credit: NASA
Long-lasting habitability on Mars: what Curiosity really found
Curiosity landed in Gale Crater in 2012 with a clear goal. It was not sent to find life. Instead, it was sent to answer a more basic question: could Mars ever have supported life at all? Gale Crater, with its central mountain Mount Sharp, holds a layered record of Martian history. Each layer captures a different climate period.
The new study focuses on a rock unit called the Stimson Formation. This formation began as large sand dunes that once marched across the floor of Gale Crater. Over time, those dunes hardened into sandstone. That alone is not surprising. What matters is how that transformation happened.
Curiosity’s instruments revealed subtle changes in texture and chemistry inside the Stimson rocks. The team found clear signs that groundwater moved through the dunes, dissolving some minerals and depositing others. This process, called lithification by groundwater, turns loose sand into solid rock. It also leaves chemical fingerprints that scientists can read billions of years later. dailygalaxy.com
Crucially, this groundwater activity did not happen during Mars’ early “ocean world” phase. It came later, after the global oceans had already begun to retreat. That means conditions suitable for microbial life—liquid water, energy sources and stable rock pores—may have persisted deep underground long after the surface became cold and dry.
In other words, Curiosity did more than tick the box for “ancient habitability.” It opened the door to something bigger: long-lasting habitability on Mars that stretched across a much longer timeline than most models predicted.
From a blue world to a frozen desert: a more complex water history
To understand why this is such a big deal, we need to zoom out. Early Mars likely had a thicker atmosphere and a stronger greenhouse effect. Under that sky, liquid water flowed in rivers, pooled in lakes and may have filled a northern ocean. This wetter phase probably peaked more than 3.7 billion years ago.
Over time, the Sun’s high-energy radiation stripped Mars’ atmosphere. As the air thinned, water on the surface became unstable. It froze, evaporated or escaped to space. The classic picture says that once this happened, Mars quickly turned into the dry, freezing desert we see today.
The Curiosity results argue for something more complicated. The team’s analysis suggests that, even as global oceans disappeared, groundwater systems survived in pockets like Gale Crater. Water could move through the subsurface, seep into ancient dunes, and chemically alter the rock over long periods. dailygalaxy.com
Mars’ climate, in this view, was not a simple “on/off” switch for water. Instead, it likely passed through cycles of wet and dry, with local regions staying habitable far longer than the global average would suggest. Shallow lakes dried out, but deep fractures and buried aquifers continued to host liquid water.
This more nuanced timeline has a direct impact on how we think about life. If long-lasting habitability on Mars is real, then the window of time during which life could emerge and adapt stretches out. Early microbes would not have needed to survive a sudden planetary death. They could have retreated underground, following the water as it went deeper.
Earth’s deserts as a window into long-lasting habitability on Mars
To decode Gale Crater’s story, the team did not rely on Martian data alone. They turned to Earth analogues in the deserts of the United Arab Emirates. In these regions, wind-blown dunes have also been transformed into rock by slow groundwater flow. The result is sandstone with cementing minerals like gypsum—very similar to what Curiosity sees on Mars. dailygalaxy.com
By comparing grain size, layering and mineral content between UAE dune rocks and Gale Crater samples, the researchers gained confidence in their interpretation. On Earth, they know exactly how long such systems can remain wet. Groundwater can persist for millions of years in desert basins, even after surface water vanishes.
Curiosity’s data show gypsum and related sulfate minerals in the Martian dunes. These minerals almost always signal the presence of water. On Earth, gypsum often forms when mineral-rich groundwater evaporates or when water circulates through porous rocks in arid environments. Seeing the same minerals in the Stimson Formation suggests that Mars followed similar rules. dailygalaxy.com
This Earth-to-Mars comparison does not prove that life existed in Gale Crater. But it does strengthen the case that the environment checked the right boxes for a long time. Subsurface water. Chemical gradients. Mineral surfaces where organic molecules could cling and react. All of these factors matter for long-lasting habitability on Mars.
What long-lasting habitability on Mars means for life
“Habitability” is a careful word. It means that an environment could support life—not that it did. So what does long-lasting habitability on Mars really change in practical terms?
First, it affects our estimate of probability. On Earth, life appears relatively early, then survives through dramatic climate shifts, asteroid impacts and ice ages. Microbes in particular are incredibly tough. They live in deep crustal rocks, polar ice, acidic hot springs and salty underground brines.
If Mars once hosted microbes, they would probably have favored similar refuges. Subsurface aquifers shield them from radiation and temperature swings. Mineral-rich groundwater offers energy sources, from iron chemistry to sulfur reactions. A short-lived wet phase might not give life enough time to start and stabilize. A long-lasting phase, especially underground, changes that calculus.
Second, long-term habitability affects where we look for biosignatures. Surface rocks that formed in ancient rivers or lakes are still important. But Curiosity’s results raise the status of cemented dunes, fracture fills and mineral veins created by late-stage groundwater. These “secondary” features could store organic molecules or isotopic clues linked to metabolism. dailygalaxy.com
Third, it changes our sense of urgency. If Mars stayed habitable beneath the surface for billions of years, then traces of life—if it ever existed—could still be preserved today. They may sit just beyond the reach of current rovers, locked inside rocks that have not yet been sampled. That makes long-lasting habitability on Mars not only a scientific concept, but also a practical guide for mission planning.
Mars Sample Return in jeopardy just as the case for it grows
This brings us to a troubling twist in the story. While the science case for Mars grows stronger, NASA’s most ambitious Mars program is facing a crisis.
The Mars Sample Return (MSR) campaign aims to pick up rock cores that the Perseverance rover is carefully caching in Jezero Crater. Those cores include ancient lakebed sediments and delta deposits that likely formed in a long-vanished river system. Bringing them home would let scientists use the full power of Earth labs—mass spectrometers, synchrotrons, nanometre-scale imaging—to search for subtle biosignatures. Scientific American
According to Scientific American, however, cost overruns and schedule risks have pushed U.S. officials to reconsider the entire program. Years of planning and billions of dollars are now at stake. The article notes that, in a worst-case scenario, the carefully collected samples might never leave Mars. Scientific American
If that happens, we lose more than a set of rocks. We lose a once-in-a-generation chance to test ideas like long-lasting habitability on Mars with laboratory-grade precision. We also weaken the argument for future missions that could target places like Gale Crater’s groundwater-altered dunes or similar subsurface systems elsewhere on the planet.
In a sense, Curiosity and Perseverance are part of the same story. Curiosity reveals that Mars stayed habitable underground for much longer than expected. Perseverance is building the first library of rocks from such a world. MSR is the bridge that connects those discoveries to definitive answers.
Shutting that bridge down now would send a clear message: we are willing to live with uncertainty about one of the biggest questions in science—Are we alone?—even when the evidence for a habitable Mars has never been stronger.
What comes next for Mars exploration
Despite the uncertainty around MSR, Mars exploration is not standing still. Curiosity continues to climb higher up Mount Sharp, moving through younger layers that record the planet’s slow shift from wet to dry. Each new outcrop helps refine the timeline for long-lasting habitability on Mars, especially in the subsurface. dailygalaxy.com
Perseverance, meanwhile, keeps drilling and caching new samples in Jezero Crater. It carries instruments that can detect organic molecules, measure rock textures and scan the chemistry of ancient sediments. While those tools cannot match a full Earth lab, they already hint at complex organic chemistry in Martian rocks.
Future missions may push even deeper. Concepts for advanced drills and cryobots could one day target buried ice layers or deep aquifers, where liquid water might still exist in small pockets. International missions, including planned Chinese and European projects, also aim to investigate Mars’ climate history and potential biosignatures with new instruments and landing sites.
In this broader context, Curiosity’s discovery is a pivot point. It tells space agencies that the most interesting stories may not lie only in obvious ancient lakebeds, but also in subtler features: lithified dunes, fracture-filled veins and mineral cements that record the hidden movement of water through rock. Those are exactly the kinds of places where long-lasting habitability on Mars would leave its mark.
Long-lasting habitability on Mars rewrites the Red Planet’s timeline
Curiosity’s latest chapter from Gale Crater does not show fossil microbes or a clear chemical fingerprint of life. Instead, it gives us something more fundamental: a new timescale. Mars did not simply flip from “habitable” to “dead” in a single dramatic moment. It faded unevenly. Oceans vanished, but water lingered underground. Surface conditions became harsh, but the subsurface stayed friendly to life for far longer than we thought. dailygalaxy.com
That is what long-lasting habitability on Mars really means. It stretches the window in which life could have appeared, adapted and perhaps endured in protected niches. It nudges us to look in new places, to design better tools and to fight harder for missions like Mars Sample Return. Scientific American
For now, the evidence is geological rather than biological. Sand dunes turned to stone. Minerals like gypsum locking in the memory of ancient groundwater. But behind those rocks lies a much larger question. If one small crater on a modest planet could stay habitable for so long, how many other worlds in our galaxy have followed the same path?