NASA’s Mars Perseverance Rover Picks Up an Unwanted Hitchhiker

TOPICS:JPL Mars Mars 2020 Perseverance Rover NASA

By EVAN GOUGH, UNIVERSE TODAY MARCH 13, 2022

NASA’s Mars Perseverance rover acquired this image of the area in front of it using its onboard Front Left Hazard Avoidance Camera A. This image was acquired on February 25, 2022 (Sol 362) at the local mean solar time of 14:24:43. Credit: NASA/JPL-Caltech

It looks like the Perseverance rover has an unwanted passenger, a rock stuck inside one of its wheels. The image of the stone was recently selected as the “Image of the Week” for the Perseverance mission. The Image of the Week is selected by public input. Perseverance captured this image on February 25th, 2022.

The rover’s Front Left Hazard Avoidance Camera A captured the image. When the rover is driving, it makes periodic stops to let the Hazard Cameras survey the immediate surroundings. The Hazard Cameras help evaluate the hazards in front of and behind the rover, like large boulders, deep trenches, or dunes. The cameras create 3D views of the surroundings that help the rover make its own decisions without consulting with the rover team on Earth on every move.

The Mars Perseverance mission carries more cameras to Mars than any interplanetary mission in history. The Perseverance rover itself has 19 cameras that will deliver images of the landscape in breathtaking detail. These include cameras for engineering (9), entry, descent and landing (3), and science (7). Credit: NASA/JPL-Caltech

The rock’s stayed there for quite a while already, based on images from March 10th. It’s difficult to tell from the picture for sure, but it doesn’t appear to be wedged in. Will it fall out during normal operations?

The rock doesn’t appear to be causing any damage or hindering the rover’s operations. And it’s not the first time a stone got stuck in a rover’s wheel. MSL Curiosity also had a rocky hitchhiker in one of its wheels.

This image from March 10th shows the rock still stuck in one of Perseverance’s six wheels. Will it fall out on its own? Is there any way to get it out? Does it matter? Credit: NASA/JPL-Caltech

NASA thinks rovers can get rocks stuck in their wheels when traversing slopes. They can also get in there as the rover moves over loose terrain and as the rover’s weight breaks rocks into pieces. In a 2017 article at Mashable, Curiosity Project Scientist Ashwin Vasavada said, “We don’t exactly know how the rocks get in the wheels, but it’s likely that they can hop in as the wheels (and heavy rover) break rocks and sink into the soil around loose rocks.”

They’ve said that rocks in rover wheels aren’t a problem in the past. The rocks are pretty soft and tend to fall out on their own. The only potential problem is if the rocks somehow interfere with cables running to the motor on each wheel.

MSL Curiosity had a rock stuck in its wheel in June 2017. Credit: NASA/JPL-Caltech

NASA doesn’t seem worried about it, though; otherwise, they would’ve changed the design to prevent it.

At least one Mars rover ended due to problems with its wheels, but not because a rock got stuck. In 2009, NASA’s Spirit Rover got one of its wheels stuck in soft soil. After months of carefully planned maneuvers and extrication attempts, NASA announced that the rover was stuck. In May 2011, they ended the mission.

Perseverance’s mission was planned to last at least one Mars year or 687 Earth days. It’s a little over halfway through its planned mission at 373 sols on March 8th.

But rover missions to Mars tend to last longer than planned. Spirit and Opportunity were supposed to last about 90 sols, but Spirit lasted 2208 sols, and Opportunity lasted 5,352 sols. MSL Curiosity has been active on Mars for over nine years, and its primary mission was set at only 687 days.

Perseverance’s planned mission length is at least one full Martian year. But it’s already exceeded that, and its Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) could last ten years or more. Hopefully, Perseverance will complete its mission and cache samples for later retrieval and even find preserved biosignatures.

Eventually, the mission will end. But it probably won’t be because of a rock in its wheel.

Originally published on Universe Today.