Curiosity rover has been crawling on Gale’s crater for almost seven years, but just now NASA engineers figured out how to use it to get new data — accurately measure the density of the Eolid mountain rock.
Usually, to measure gravity on Mars or other planets, scientists need data from orbiting satellites, such as the MRO, the Martian reconnaissance satellite. But due to the considerable distance to the target, its capabilities are limited. For example, the MRO barely distinguishes the Gale crater with a diameter of 150 km, writes EurekAlert.
NASA engineer Kevin Lewis had the idea to calibrate the rover accelerometers in such a way that they measure surface gravity while lifting Curiosity to Mount Eolid (this is Sharpe Mountain). Accelerometers of the rover are about the same as with a conventional smartphone – measure the position of the device and help in navigation.
As it turned out, Curiosity had already collected hundreds of measurements during its missions, and the Lewis team used them to detect the smallest changes in gravity.
For starters, they took into account the rotation of Mars, then calibrated the raw data, taking into account the effects of temperature, the tilt of the rover, and other factors. And they were surprised when they discovered that Curiosity was moving in a low-density rock, although the readings from the CheMin tool (carrying out chemical and mineralogical analysis) indicated that this was not the case.
After examining what lies beneath the surface of Mars, and measuring the difference in gravity, scientists were able to learn more about the planet and its past. In particular, it used to be thought that Gale’s crater was completely composed of sedimentary, that is, dense rock, and the Eolide mountain emerged from these layers due to erosion.
However, the porosity of the stones indicates that the mountain was formed differently. Perhaps the upper layers were formed by exposure to winds, not water.
Last fall, scientists unraveled another riddle of the Red Planet, more precisely, its satellite Phobos. Computer modeling showed how the characteristic grooves appeared on it.