Washington: NASA's Perseverance rover has set a new record for the longest distance travelled by any vehicle on a world beyond Earth, marking another milestone in humanity's exploration of Mars.
The US space agency announced that the six-wheeled, car-sized rover has travelled 28.1 miles (45.2km) since landing on the Red Planet more than five years ago, surpassing the previous record set by NASA's Opportunity rover, which operated from 2004 to 2018. Both rovers have also covered greater distances than any rover deployed on the Moon.
Perseverance, equipped with a suite of scientific instruments, has been searching for evidence of ancient microbial life on Mars, a planet believed to have been warmer and wetter billions of years ago than the cold, arid world it is today. The rover has also been collecting rock and soil samples that could eventually be returned to Earth for further study.
Jezero Crater mission
Since landing on February 18, 2021, Perseverance has been operating in and around Jezero Crater in Mars' northern hemisphere. Scientists believe the crater once contained a lake and was flooded with water billions of years ago.
NASA said the rover achieved the distance milestone on Sunday while travelling towards an area known as Idubi through a region on the crater's western rim nicknamed Lac de Charmes. The region contains some of the oldest terrain ever studied in the solar system.
Perseverance is one of two NASA rovers currently operating on Mars. The Curiosity rover, which landed in Gale Crater near the Martian equator in 2012, has travelled 23.71 miles (38.15km).
Steven Lee, project manager for the two rover missions at NASA's Jet Propulsion Laboratory in California, said Perseverance remains in excellent condition.
"Perseverance's engineering hardware and instruments are in excellent shape, with all redundant systems still available. A recent assessment of all systems concluded that they are capable of operating well into the 2030s, likely beyond," Lee told Reuters.
China's Zhurong rover also gathered valuable scientific data during its operations in the Martian northern lowlands between 2021 and 2022.
Autonomous navigation
Perseverance frequently relies on its autonomous navigation system, known as AutoNav, to traverse the Martian landscape. Lee said approximately 90% of the rover's driving is completed autonomously without direct human intervention.
"Perseverance takes stereo images of the terrain ahead, generates a 3D software map, and selects the safest path towards a drive goal," he said.
The rover also uses a Vision Compute Element co-processor, enabling it to process images and execute navigation software rapidly while on the move. Earlier Mars rovers were required to stop and analyse their surroundings before continuing their journeys.
"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.
The rover's mobility system is being tested to demonstrate a driving capability of at least 100km (62 miles), while the hardware is expected to be tested to the equivalent of 150km to 300km (93 to 186 miles).
Search for ancient life
Lee said Perseverance's most significant achievement to date is likely the discovery, announced last year, of a potential biosignature, a possible indication of ancient microbial life.
The finding was made in a 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 within Jezero Crater.
According to Lee, the rocks in the Lac de Charmes region could provide important clues about early planetary geological processes, including the effects of major meteorite impacts. Jezero Crater itself was created by such an impact early in Mars' history.
"The terrain we're currently exploring may contain rocks older than any found on Earth," Lee said.
Perseverance's original mission called for approximately 20km (12.4 miles) of driving. NASA has since approved an extension of the mission through to roughly the end of 2028, allowing continued exploration of the crater rim.
"There is evidence from orbital measurements that some areas of the rim were once hydrothermal systems with warm or hot groundwater. These areas may once have provided a warm, watery subsurface environment conducive to life. Indeed, some palaeontologists hypothesise that life on Earth began in such environments," Lee said.
The rover's plutonium-powered energy system continues to perform as expected and still has many years of useful operational life remaining, he added.