One of NASA’s intrepid Mars rovers unexpectedly changed course to avoid dangerous “gator-back” terrain.
That Curious Rover, exploring Mount Sharp, spent most of March climbing the south side of a gentle slope called the “Greenheugh Pediment” where it encountered mainly stony sandstone. On March 18, the Rover team took off again Earth discovered unexpected terrain littered with windswept rocks called ventifacts. In response, the drivers decided to turn the research robot around a statement from NASA’s Jet Propulsion Laboratory (JPL) in California, which is leading the mission.
Earlier in his mission Mars, Curiosity had encountered similar vents that damaged the rover’s wheels. However, the rover’s most recent rock photos revealed more ventifacts than the team has seen in Curiosity’s nearly 10 years on the red planet, according to the statement.
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Ventifacts are made of sandstone, the hardest rock Curiosity has encountered since landing on Mars Gale Crater on August 6, 2012. Scientists have nicknamed the Ventifacts “gator-back” terrain because of the scale-like appearance of the structures.
Since the rover first encountered this type of hazardous terrain, the mission team has worked to reduce wheel wear, relying on orbital imagery to determine safer routes for the rover to prevent it from overshooting driving dangerous terrain. However, as Curiosity neared the south face of the Greenheugh Pediment — a 1.2-mile (2-kilometer-wide) sloping plain near the base of Mount Sharp — it saw the rocky terrain up close, revealing to mission engineers how dangerous the vents were are.
“It was obvious from Curiosity’s photos that this would not be good for our wheels,” Megan Lin, JPL’s Curiosity project manager, said in the statement. “It would be slow, and we wouldn’t have been able to implement best practices for driving rovers.”
While the alligator rocks would not have been impassable, traversing the terrain would have increased wear on the wheels and jeopardized their longevity. So the team is charting a new course Mount Sharpthe 5.5-kilometer mountain that Curiosity has climbed since 2014.
Scientists originally aimed the rover at the Greenheugh Pediment to better understand how the distinct feature formed. This area is also near the Gediz Vallis Ridge, which planetary scientists believe was formed by debris flowing down the mountain. Therefore, exploring the tricky rocks may have uncovered new evidence of material originating from the uppermost reaches of the mountain.
“From afar, we can see car-sized boulders being carried down from higher levels of Mount Sharp – perhaps by water relatively late in Mars’ wet era,” said Ashwin Vasavada, Curiosity’s project scientist at JPL, in the statement. “We don’t really know what they are, so we wanted to see them up close.”
Instead, Curiosity will now climb down from the pediment, back into a safer area it previously explored – a transition zone between clay-rich terrain and one with higher levels of salt minerals known as sulfates. This area helps scientists better understand Mars’ ancient past as the clay minerals should have formed the mountain was wetterwhile the salts are said to have formed as the planet’s climate dried out over time.
“It was really cool to see rocks that preserved a time when lakes dried up and were replaced by streams and dry sand dunes,” said Abigail Fraeman, Curiosity’s associate project scientist at JPL, in the statement. “I’m really excited to see what we find as we continue climbing this alternative route.”
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https://www.space.com/curiosity-rover-dodging-gator-back-terrain-photo NASA’s Curiosity Mars Rover Turns to Avoid Dangerous ‘Gator Back’ Rocks (Photos)