NASA’s Curiosity rover is making a pit stop as it continues heading up the slopes of Mount Sharp. On the northwestern edge of Mount Sharp lies a series of dark dunes dubbed “Bagnold Dunes.” It’ll mark a first for the Curiosity mission and NASA. No Mars rover has ever visited a sand dune. Drifts sure, but never a dune. One of the dunes is 20 feet tall and stretches a football field.
And NASA says they are active. Orbital images show some of the Bagnold Dunes moving as much as 3 feet per Earth year.
It’s hard to make out in this image. Here’s a better example imaged between 2007 and 2010.
NASA scientists want to learn more about what’s driving this activity. Curiosity should also “help us interpret the composition of sandstone layers made from dunes that turned into rock long ago,” says Bethany Ehlmann of Caltech and NASA’s JPL.
On Monday, Curiosity was still about 200 yards away from “Dune 1.” It’s taking wind direction and speed measurements every day and taking images as it inches closer. Once there, Curiosity will use its scoop to collect samples for analysis. The rover’s team gets to have a little fun too as they use a wheel to scuff the dune. Scientists want to see the differences between the dune’s surface layer and what lies just beneath.
Sand dunes on Mars versus Earth
Sand dunes on the red planet have a different texture than ones found on Earth. They’re much larger, and scientists aren’t sure why. Scientists point to lower air pressure as a possible reason. “It takes a higher wind speed to get a particle moving,” according to Nathan Bridges from Johns Hopkins University’s Applied Physics Laboratory. “But now we’ll have the first opportunity to make detailed observations.
Another question scientists are tackling is if wind is sorting the materials in the sand dunes. Observations from the Mars Reconnaissance Orbiter shows the distribution of minerals is not even in the dunes.
“We will use Curiosity to learn whether the wind is actually sorting the minerals in the dunes by how the wind transports particles of different grain size,” says Ehlmann.
Curiosity’s 3+ years of travelling
On August 6, 2012, Curiosity began its journey on Mars. In April 2015, Curiosity’s odometer tripped past 10 kilometers (6.2 miles). Not quite the marathon milestone of Opportunity, but still a respectable distance.
After landing, Curiosity studied the Gale Crater. Today, it continues through the foothills of Mount Sharp. Check out the rover’s path to Bagnold Dunes below.