Researchers Measured the Density of Rock Layers in Gale Crater

The Curiosity Rover of NASA has discovered that the rock layers of Mars are more porous than previous estimates.

A team of researchers analyzed the non-science engineering data from the Curiosity Rover and determined the density of rock layers across the Gale Crater. Travis Gabriel, a Graduate Student in the School of Earth and Space Exploration at the Arizona State University, computed the grain density for the ancient rocks and lakebed sediments of the red planet. This study has given scientists an efficient method for future as the rover continues its journey towards the Mount Sharp. He found that the rate of compression on these rock layers have been slower than expected, probably because the rocks were more porous. Gabriel explained the findings in the following words:

“What we were able to do is measure the bulk density of the material in Gale Crater. Working from the rocks’ mineral abundances as determined by the Chemistry and Mineralogy instrument, we estimated a grain density of 2810 kilograms per cubic meter. However, the bulk density that came out of our study is a lot less — 1680 kilograms per cubic meter.”

Engineering Sensors

The sensors (gyroscopes and accelerometers) involved in this research are quite similar to what we have in our smartphones. In the case of a smartphone, the task assigned to these technologies is to determine the motion and orientation of the device. The sensors of the Curiosity Rover do exactly the same but with more much precision. Consequently, the engineering team of the rover can control the movement of the spacecraft across the Martian surface. In addition to that, these accelerometers can also measure the local gravity on Mars.

The data from the first 5 years of the mission was considered for this research. The researching team examined the local gravity at around 700 points (along the path of the rover) during this span and found that the results didn’t match with their expectations. Scientists expected the gravitational tug to be stronger in recent years as Curiosity is ascending Mount Sharp but that didn’t happen. Kevin Lewis, the Lead Author of the study who is a representative of the John Hopkins University, explained these variations and said,

“The lower levels of Mount Sharp are surprisingly porous. We know the bottom layers of the mountain were buried over time. That compacts them, making them denser. But this finding suggests they weren’t buried by as much material as we thought.”

Rock Layers of Mount Sharp

The origin of Mount Sharp has always been a bit of a mystery for planetary scientists. According to a popular belief, these central peaks in Gale Crater are formed by the shock of the impact which created the crater. Having said that, this impact could only produce a part of the mound’s height. As it seems, the upper rock layers of the mound are made up of wind-scoured sediments, which are eroded much easily than rocks. If we believe the theory that these sediments once filled the entire Gale Crater, they must have weighed heavily on the materials at the base. Contrary to that, the latest research shows that the lower rock layers of Mount Sharp have been compacted by 1 to 2 kilometers of material. Ashwin Vasavada, the Project Scientist of Curiosity Rover, referred to the importance of this research by saying,

“There are still many questions about how Mount Sharp developed, but this paper adds an important piece to the puzzle. I’m thrilled that creative scientists and engineers are still finding innovative ways to make new scientific discoveries with the rover.”

Gabriel also talked about the significance of this discovery and acknowledged the benefits of equipping Curiosity Rover with a diverse set of techniques. He also mentioned that the scientific community is waiting eagerly to observe the upper rock layers of Mount Sharp. He said,

“This is a testament to the utility of having a diverse set of techniques with the Curiosity rover, and we’re excited to see what the upper layers of Mount Sharp have in store.”