The Mars rover Perseverance, NASA's most advanced robotic explorer to date, almost five years after its spectacular landing in Jezero Crater, is still going strong. In that period, it has traveled nearly 25 miles, or about 40 kilometers, collecting samples of rock and regolith and taking detailed photographs and measurement data that could answer one of humanity's oldest questions: was there once microscopic life on Mars?

While political decisions, budgets, and plans for future missions change on Earth, Perseverance continues its daily routine of driving, drilling, and analysis on the Red Planet. The rover moves across the extremely demanding terrain of an ancient river delta in Jezero Crater, an area scientists believe was home to a lake billions of years ago where sediments were deposited – a perfect archive for traces of ancient microorganisms. That is precisely why engineers at NASA's Jet Propulsion Laboratory (JPL) in California emphasize that the key task of the mission in the coming years is to maximize the rover's mobility and its ability to "drive" scientists to the most diverse rock formations possible.

A Rover Designed for Marathon Stretches

Perseverance landed on Mars on February 18, 2021, as the centerpiece of the Mars 2020 mission. It was designed based on the success of the Curiosity rover but with a series of technological upgrades: more robust wheels with an improved profile, a more advanced navigation system, faster autonomous route planning, and a complex system for sampling and storing rock core samples in metal tubes. It is powered by a radioisotope thermoelectric generator, which converts the heat from the decay of plutonium into electricity – meaning the rover does not depend on solar panels and is expected to operate for many years, even when dust storms and long winter months prevail on Mars.

The rover's platform carries a range of instruments tailored to various scientific tasks. Mastcam-Z provides high-resolution panoramic and telephoto images, SuperCam can "shoot" rocks with a laser and analyze vapors, PIXL investigates chemical composition on a microscale, and SHERLOC looks for traces of organic molecules. Combined with the RIMFAX radar that "peers" beneath the surface, these instruments allow every rover stop to be detailedly "dissected" in both depth and width – from microscopic structures to the geological context of entire rock layers.

Such equipment only makes sense if the rover can truly move over long distances and reach various types of terrain. That is why mobility was one of the key design points from the start. Perseverance has six drive wheels with independent suspension and the ability to swivel the front and rear axles, allowing it to turn almost in place and overcome rocks up to 40 centimeters high. Despite this, the team on Earth avoids unnecessary risks: every slope, every stone, and every patch of sand is observed with a great deal of caution.

AutoNav: Artificial Intelligence for Driving on Mars

In the coming years of the mission's operational life, the emphasis will be on driving – literally "miles under the wheels." The JPL team estimates that Perseverance has enough reserve in its drive, electronics, and power system to travel dozens more kilometers through diverse geological units around Jezero Crater. Every new meter brings an opportunity to discover a different type of rock, transitions between sedimentary layers, ancient riverbeds, or deltaic structures that hold records of the environment that prevailed on Mars more than three and a half billion years ago. It is precisely such transitions – boundaries between different rock units – that are key to interpreting the history of water and potential niches for life.

To achieve maximum efficiency, the rover increasingly relies on automated navigation. The system known as AutoNav analyzes 3D data from stereo cameras on the mast and, based on them, selects a path in real-time that bypasses large rocks, steep edges, and potential holes. Instead of engineers on Earth pre-planning every single drive based on satellite images and photos, they now more frequently define only a "target zone," while algorithms on the rover independently find the best route. This saves precious time in deep-space communication, and the rover can travel hundreds of meters in a single sol (Martian day), which was almost unthinkable a few years ago.

Perseverance has already broken several records during the first years of the mission. On some days, it managed to cover more than 400 meters in a single driving stint, surpassing previous Mars rovers in the length of a single leg. Such long straight-line "marches" across the surface of Mars require exceptional confidence in sensors and software, because any wrong decision could lead to the rover getting stuck in the sand, driving over sharp rocks, or encountering a steeper slope than the wheel construction allows. That is why JPL continuously upgrades the rover's software, introduces new safety checks, and adjusts driving parameters based on experience gained in the field.

Over time, the routes themselves began to be planned more ambitiously. At the beginning of the mission, the emphasis was on short segments and detailed checking of every forward drive, but now it is often planned to combine multiple driving segments in one sol, with shorter stops for quick photos and checks. When the terrain allows, Perseverance covers dozens or hundreds of meters without human intervention, relying on its own risk assessment based on images and depth maps it creates on the go.

Cheyava Falls: A Promising Valley for Traces of Life

Driving, of course, is not an end in itself. The main scientific goal of the mission is to find rocks that could preserve microscopic traces of past life – so-called potential biosignatures. In this sense, the path the rover has traveled in recent years from the landing site to the area known as Cheyava Falls is crucial; it is an ancient river valley where layered, colorful rocks rich in minerals that often form on Earth in interaction with microorganisms were discovered.

Analyses of such rocks showed the presence of minerals like vivianite and greigite, as well as complex textures resembling poppy seeds or "leopard spots," which, according to some scientists, could point to ancient microbial activity. Although direct proof of life has not yet been found, these are the most compelling traces so far that Mars could once have been habitable. Samples from that area are stored in metal tubes, which should be retrieved by a separate Mars Sample Return mission to Earth in the future.

By the fall of 2024, the rover had already traveled more than 30 kilometers and collected more than twenty samples of rock and regolith, as well as one sample of the Martian atmosphere. Each of these cylinders carries a unique geological signature – from the sedimentary rocks of the delta to volcanic substrates and materials altered by water. This "traveling archive" will allow for a precise reconstruction in terrestrial laboratories of how the climate and chemistry of Mars changed over billions of years.

MOXIE, Ingenuity, and Technological Experiments

Parallel to geological research, Perseverance performs technological demonstrations key to future missions. One of the most famous experiments was MOXIE – a device that successfully produced oxygen from the thin Martian atmosphere rich in carbon dioxide. That demonstrator has finished its campaign, but the results showed that similar technology could be used in future human missions to obtain oxygen for breathing and as a component of rocket fuel. The rover also served as a base for the first helicopter on another planet, Ingenuity, which completed 72 flights in nearly three years and proved that aerial scouting on Mars is not only possible but extremely useful.

Ingenuity suffered rotor-blade damage in early 2024, so NASA decided to end its active mission. The helicopter still stands on the surface of Mars as a kind of monument to the first flight in another world, while Perseverance continues solo. However, the experience gained in tandem driving with the helicopter directly influences how future rover routes are planned: aerial data showed where the most interesting rock formations are and where dangerous terrains to be avoided are hidden. In the years to come, a new generation of robotic and perhaps one day human explorers will rely on this pioneering combination of wheels and rotors.

As part of the technological demonstrations, Perseverance occasionally takes its own "selfies." One of the most visually impressive depictions was recorded when the rover, while documenting its drill holes on the ground, captured a passing dust vortex – a Martian "dust devil" – on the horizon. The composite images show the fine swirl of dust several kilometers behind the rover, while its body is covered in a layer of reddish powder. Such photographs do not only serve the popularization of science; they allow engineers to monitor equipment wear and the impact of Martian dust on instruments.

Samples for Future Generations of Scientists

A large part of the mission's scientific value lies in the carefully selected rock core samples that the rover drills and hermetically seals in metal tubes. By the end of the mission, Perseverance is expected to leave a collection of dozens of samples on the surface of Mars at strategically chosen locations. It is planned that in a future Mars Sample Return campaign, new landers and small helicopter-drones will retrieve them and send them into orbit, from where they would be transferred to a return capsule to Earth. There, they would be analyzed by laboratories with instruments many times more sensitive than anything possible to place on a rover, which opens the possibility for scientists to look for fine signature signals of former biochemical processes in traces of minerals, organic molecules, and isotopic ratios.

However, the sample return program is under pressure today from budget cuts and political decisions. NASA and its partners are working to reduce costs and redesign the mission architecture to keep the project within limits acceptable to taxpayers while simultaneously fulfilling scientific goals. For Perseverance, this means that every sample it chooses must have maximum scientific "weight," as there may not be a chance for a second attempt. The team on Earth therefore pays extra attention to the interpretation of spectroscopic data, microscopic images, and geological context before ordering the drilling and storage of a core.

To minimize risk, samples are collected from different types of rocks: fine sedimentary deposits that once settled in calmer waters, coarse conglomerates formed in faster river flows, altered rocks that changed their composition through the action of water or heat, and volcanic rocks that provide time stamps for the entire region. By combining these samples, scientists hope to draw a chronology of the lake system in Jezero Crater – when it formed, how long it existed, how deep it was, and what chemical conditions it offered to potential microscopic life.

A Long Drive Through an Uncertain Future

While the budget and final architecture of the sample return are being debated, the rover continues its work in the field almost undisturbed. Delays in decisions on Earth do not change the fact that Perseverance records new kilometers and new scientific insights on Mars every sol. Its path through Jezero Crater and toward the elevated, eroded slopes acts like a carefully drawn geological map, where each point represents a combination of measurements – from the chemical composition of the rock and its magnetic response to photographs in different spectral ranges. This comprehensive database, which expands day by day, will remain the legacy of the mission for decades after the rover's wheels finally stop.

The perspective of a "long drive" also means that the team is thinking several years ahead. Route plans include consideration of seasonal changes on Mars, statistics on the frequency of dust storms, terrain slopes, and the schedule of satellite flyovers that serve as communication relays. Every new segment of the path must fit into a larger mosaic: how to reach scientifically attractive targets as quickly as possible while preserving the rover's health. There are also "service stations" where Perseverance takes detailed shots of its own wheels, instruments, and systems so that engineers on Earth can monitor material wear, cracks in tires, and the condition of mechanical joints.

Perseverance, like every long-lived robot in deep space, is also a story about the team of people who "drive" it daily from a distance of nearly 300 million kilometers. The control center at JPL has adapted its work shifts to the Martian day, which lasts slightly longer than 24 hours, meaning schedules are constantly shifting. Engineers and scientists work in cycles of planning, execution, and analysis: during one day new tasks are defined, the next sol those tasks are executed on Mars, and after the data returns, a detailed analysis begins that shapes the next steps. This rhythm, now well-established, allows the rover to progress through the terrain almost continuously.

For the wider public, Perseverance is a symbol of persistence and curiosity – exactly what its name means. Every new kilometer the rover drives on Mars is a reminder that this is a long-term mission, which does not bring quick answers but slowly assembles the mosaic of a planet's history. In the years to come, while the rover continues to "roll kilometers" through Jezero Crater and beyond, scientists expect even more ambitious drives, more complex geological targets, and new samples that could one day end up in terrestrial laboratories. Even if the final answer about the existence of ancient life on Mars is negative, the path Perseverance travels will remain one of the most impressive research chapters in the history of robotics and planetary science.