The Mars rover accidentally adopted a pet stone

Life for Perseverance, the brave rover that currently roams the red planet about 132 million miles from Earth, is quite lonely. From the desolate, dusty landscape of the Jezero crater to the mighty Martian winds, life on Mars is not for the faint of heart – or at least for those who are extroverted. Therefore, despite being a robot on a scientific research mission, scientists on NASA’s Perseverance mission team were recently surprised to discover that Perseverance had accidentally adopted a pet stone.

It is unclear whether Perseverance chose the stone or the stone chose Perseverance, but researchers say the stone has found a cozy home on the rover’s front left wheel, and then it began to cling to it. According to a NASA news release about the rock, the rock has been there since early February and has traveled more than 5.3 miles around Mars; Perseverance itself has traveled a total of 7.3 miles since falling on Mars in February 2021. Fortunately, the stone has not caused any damage to Perseverance, although it has certainly lived up to its owner while enduring clinging to the rover after so many miles.

Stein is stuck in the shoe of the Perseverance roverStein is stuck in the shoe of the Perseverance rover (NASA / JPL-Caltech)

This is not the first time a rover has used a rock – or rather, that a rock has chosen a rover. Almost 18 years ago, a potato the size of a potato attached itself to the right wheel of the Spirit rover, which operated on the surface of Mars from 2004 to 2010. Mission operators eventually had to remove the intruder externally. The Curiosity rover, which landed on Mars in 2012, saw rocks periodically get stuck in the front right wheel. However, researchers say that this type of rover-rock relationship usually lasts only a few weeks – not months.


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Since landing on Mars in February 2021, Perseverance has compiled an impressive list of first places. For example, the rover’s combined mission marked the first time a helicopter was flown on another planet. Endurance also managed to extract oxygen from the red planet’s carbon dioxide atmosphere, a method that could one day be used to give astronauts oxygen on Mars. And perhaps most importantly, Perseverance has successfully collected and stored soil and rock samples that will eventually become the first Martian rocks to return to Earth for scientific study. And it has now also had a pet stone for the longest period of time of any rover – almost four months and counts. Is there anything perseverance can not do?

In other Perseverance news, an article published in Science Advances described Perseverance’s observations of hundreds of dust devils and its famous video of gusts of wind lifting a massive cloud of dust from Mars. Researchers say that Perseverance’s observations of these weather phenomena, made during the first 216 March days of the adventure, may help predict dust storms on Mars in the future.

Related: Mars’ strange geology annoys scientists

“The Jezero Crater may be one of the most active sources of dust on the planet,” Manuel de la Torre Juarez, assistant chief investigator at NASA’s Jet Propulsion Lab, said in a press release. “Everything new we learn about dust will be useful for future missions.”

The authors of the study discovered that at least four whirlwinds pass Perseverance on a typical March day – making the resilience of Perseverance’s rock friend even more remarkable and impressive.

Is an end to the mountain’s journey in sight? Scientists suspect that the rock may fall off during a future ascent of the crater rim due to gravity. And if it does, it will land in an area of ​​rocks that are very different from itself. As Eleni Ravanis, a student partner at the University of Hawaiʻi in Mānoa, explained in the press release about the rock, a future Mars geologist would be confused about the location of the rock.

“So: if you are a future Mars geologist reading this, perhaps a Mars student tasked with mapping the historic site of the Jezero crater: pay attention,” Ravanis wrote. “If you’ve found a stone that looks out of place, you might just look at Perseverance’s previous pet clip.”

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