Scientists find auroral "speed bumps" more complicated

Researchers at the Space Science Center at the University of New Hampshire have found that "slowdowns" in space, which can slow down satellites in orbit closer to Earth, are more complex than expected at the # 39; origin.

"We knew these satellites were coming up against" speed bumps ", which slowed them down and brought them down at altitude," said Marc Lessard, a physicist at UNH. "But during this mission, we were able to understand why this happens by discovering that bumps are much more complicated and structured."

In the study, published in the journal of AGU Geophysical Research LettersScientists describe their observations during the Rocket Experience mission for Neutral Upwell 2 (RENU2) concluding that a type of high altitude aurora, or aurora borealis, is responsible, at least in part, the displacement of very high air pockets in the atmosphere can cause a drag on passing satellites, similar to driving a car in a strong headwind. These auroras, seen from the observatory Kjell Henrickson in Norway, are not the typical bright rays of light that we see in the night sky under the high latitudes of the Earth. Known as the Poleward Mobile Auroral Shapes (PMAF), these auroras were less energetic, darker and faraway.

Scientists have long suspected that auroras could be at the origin of upwelling events affecting low-altitude satellites, as, when they fly overhead, they would encounter "slowdowns in space velocity" caused by the warming of the thermosphere at very high altitude. But as they occur at such high altitudes, these low-energy auroras transfer more of their energy into the thin atmosphere at 250-400 km above the ground and produce more interesting effects than more familiar auroras. , which sparkle. closer to 100 kilometers (60 miles).

"You can think of satellites traveling in air pockets or bubbles similar to those of a lava lamp, as opposed to a smooth wave," Lessard said.

When the first space programs put the satellites in orbit for the first time, they found the degradation of their orbit when the sun was active. The problem is that when the extra drag slows the satellites, they get closer to the Earth. Without additional fuel to revive, they will eventually fall back on Earth.

These specific satellites, which orbit in this area closer to Earth, are important because they take all the responsibility to take photos of the Earth to provide updated information for climate monitoring, agricultural yields, urban planning , disaster response and even military intelligence.