NASA's Perseverance rover has driven farther than any other vehicle on the surface of another world, covering 45.2km on Mars since arriving on the planet in 2021, the US space agency said on Tuesday.
The car-sized, six-wheeled rover reached the milestone about five and a half years into its mission to investigate whether conditions suitable for microbial life ever existed on Earth's neighbouring planet.
In the process, it has traversed some of the oldest terrain explored in the solar system.
“Perseverance's engineering hardware and instruments are in excellent shape with all redundant systems still available,” Steven Lee of NASA's Jet Propulsion Laboratory in California told Reuters.
A recent assessment found that the rover's systems could remain operational well into the 2030s, and potentially beyond, said Lee, project manager for NASA's two Mars rovers, Perseverance and Curiosity.
Perseverance has surpassed the previous record of 45km set by NASA's Opportunity rover, which travelled across the Martian surface between 2004 and 2018. Both rovers have also exceeded the driving distances achieved by any vehicle on the Moon.
Perseverance has focused its scientific investigations on Jezero Crater in Mars' northern hemisphere, a region believed to have been flooded with water and contained a lake basin billions of years ago.
The rover reached the milestone while travelling towards an area known as Idubi, crossing terrain beyond the crater's western rim nicknamed Lac de Charmes.
Its companion rover, Curiosity, continues to explore Gale Crater near the Martian equator.
Perseverance shows no signs of slowing down, Lee said.
NASA is testing the rover's mobility systems to demonstrate their ability to cover 100km or more. The hardware will also undergo tests equivalent to driving between 150km and 300km, he said.
NASA credited much of the rover's success to AutoNav, its autonomous navigation system. Around 90% of Perseverance's driving is carried out without human intervention, Lee said.
“Perseverance takes stereo images of the terrain ahead, generates a 3D software map, and selects the safest path towards a drive goal,” he said.
Another key component is the Vision Compute Element, a high-speed co-processor that allows the rover to process images and run its self-driving software almost continuously while moving, Lee added.
Earlier Mars rovers had to pause to process information before proceeding with each section of a drive, he said.
“Perseverance builds on the 29-year legacy of our past Mars rovers — Sojourner, Spirit, Opportunity and Curiosity — each incorporating prior lessons and improving our ability to drive on another world,” Lee said.
Lee said one of Perseverance's most significant achievements was its discovery, announced last year, of a potential biosignature — a possible indication of ancient microbial life.
The finding came from reddish rock believed to have formed between 3.2 billion and 3.8 billion years ago in a river channel that once fed the lake in Jezero Crater.
The Lac de Charmes terrain could offer further clues about early geological processes on Mars, including the effects of large meteorite impacts. Jezero Crater itself was formed by such an impact early in the planet's history.
Lee also pointed to evidence from orbital observations suggesting that parts of the crater rim once hosted hydrothermal systems, where warm or hot groundwater circulated.
“These areas may once have provided a warm, watery subsurface environment conducive to life,” he said. “Indeed, some paleontologists hypothesize that life on Earth began in such environments.”
Perseverance's original mission plan called for it to travel just 20km. NASA recently approved an extension allowing the rover to continue exploring the crater rim until around the end of 2028.
Its plutonium-powered energy system is performing as expected and has “many years of useful energy still available”, Lee said.