Curiosity, a NASA star robot on Mars, created a new discovery of gravity on the red planet: they could measure what is called a "gravity tug".
In an article published in Science magazine, researchers responsible for this US space agency research program described in detail how they transformed the sensors used to control the rover and transform them into gravimeters.
Thus, they managed to measure gravity traction changes. This has allowed them to measure fine hand layers at the bottom of Mount Sharp, which increased by 5,000 meters from the base of the Gale Crater, and that curiosity has increased since 2014. t
Mount Sharp is a Mars planet, forming the central peak of the Gale Crater and at an altitude of about 5,000 meters. (CC2)
Results? It turns out that the density of these rock layers it is much smaller than expected.
Like a "smartphone", curiosity takes accelerometers and gyros. When you move your smartphone, these sensors can determine the location and user movement. Curiosity sensors do the same, but with much greater precision, and are crucial for Mars surface navigation in each unit. By knowing the orientation of the vehicle, engineers can also accurately orient themselves to their tools and a great multi-directional antenna.
Like Apollo 17 on the Moon
In a scientific study, there was a pre-conception where they made Apollo 17 astronauts in 1972 when they were performing the SUV on the lunar surface and measured gravity with a special tool. Similarly, the Apollo 17 gravimeters can use Curiosity rover accelerometers. they reveal the gravity of the planet when the rider stops.
Using engineering data from the first five years of the mission, the authors write Mars gravity tug on a rover. As curiosity climbed up Mount Sharp, hill adds extra weight but not as much as the scientists expected.
"The lower levels of Sharp Hill are surprisingly porous," said leading author Kevin Lewis of John Hopkins University, "We know that the bottom layers of the hill were buried over time, which compresses them, making them denser. But this conclusion suggests they were not buried with all our material. "
The Apollo 17 astronauts drove their "buggy" using the Taurus-Littrow Moon Valley, periodically stopping 25 measurements. Lewis studied Mars' gravitational fields using data collected by NASA and got acquainted with the Apollo 17 gravity meter.
Planet Mars (US Geological Survey)
The science paper uses measurements from over 700 Curiosity accelerometers from October 2012 to June 2017. These data were calibrated filter "noise"as the influence of temperature and rover slope during its take-off. The calculations were then compared to Mars gravity field models to ensure accuracy.
The results were also compared with the Curiosity chemical and mineral instrument mineral density estimates that characterize the crystalline minerals in the stone samples using an X-ray beam that helped determine the degree of porosity of the samples. rocks
The craters or canyons have many mountains on Mars, but little on the Sharp Hill scale. Scientists are still not sure how Gale crater grew. One idea is that the crater was full of sediment. How much it was filled is still the source of the debate, but the idea is that many millions of years of wind and erosion finally came out of the mountain.
If the crater was filled to the edge, the whole material would be forced or crushed in many fine-grained sediment layers beneath it. However, the new study shows that Sharp's lower layers were only compressed from 1 to 2 kilometers, far less than the crater was completely full.
Lewis said Mars had a lot of secrets outside Sharp. Its landscape is similar to that of the Earth, but the wind and sand are more sculptures than water. They are the brothers of the planet, both familiar and completely different.
Source: DPA / Europa Press