At noon, when the Sun is at its highest point, a curious and mysterious phenomenon is registered 250 miles – about 400 kilometers – above the North Pole that brings aerospace engineers headlong: for some reason not yet clarified, the spacecraft travel slower and GPS and communications signals are interfered with. After several years of polishing details, NASA has just launched a program to clarify what the explanation is. It is not just about satiating curiosity or solving an unknown. The information obtained by the US agency will be valuable, for example, to anticipate changes in the trajectories of the ships.
NASA’s mission, christened CREX-2, seeks to analyze the solar cusp, a funnel-shaped gap in the magnetic field of our planet that protects us from the solar wind, the stream of charged particles thrown by the star. The opening – the US agency details – allows the solar wind direct access to the atmosphere. For decades, experts have been aware that when moving through this area, signals behave strangely and spacecraft slow down, “they feel more dragged”, in the words of Mark Conde himself, a physicist at the University of Alaska Fairbanks. and principal investigator of CREX-2.
An explanation that is missing the keys
Scientists know that the air at the cusp is denser at that point on the North Pole than in the rest of the exosphere. And not a little, precisely. Its density increases about one and a half times. “You cannot simply increase the mass in a region by a factor of 1.5 and do nothing more,” admits Conde in a NASA note. The challenge is to clarify why, explain the phenomenon and unravel its reasons. That’s where CREX-2 comes in.
After careful planning and seeing how its original schedule was delayed by the pandemic, the mission took a crucial step just a few days ago, the early morning of December 1, at the Andøya Space Center in Norway: At 3:25 a.m. EST a rocket was launched equipped with 20 cans similar to soda cans but programmed to break at different altitudes.
The devices, equipped with small motors and designed to expand in four different directions, have a key mission: to release vapor tracers, particles like those that can be seen in the displays with fireworks. The charge spread by each of the boats painted a bright trace in the sky that showed scientists how air moves in the atmosphere. According to NASA, the mission’s rocket, Oriole IV, reached a peak of 392 miles, 630 km.
From the ground, a group of scientists spread across Scandinavia, including Svalbard and even a plane that flew over Reykjavik, was in charge of photographing the drawing of the tracers and producing a three-dimensional map that will help solve the mystery. The test was not easy. NASA confirms that “CREX-2 payload launched successfully” and preliminary reports show that “the flight was successful and the blisters worked as planned,” but the mission required careful planning to the millimeter and with little room for error. Only a few days before, Conde recognized that each day there are only one or two hours with suitable conditions for the test. “We are threading a needle,” joked the physicist to make clear the complexity of the operation.
Pending CREX-2 findings to be revealed, scientists shuffle different explanations. One would be in the electrical and magnetic effects of the ionosphere, the layer of the upper atmosphere ionized by the Sun. Another explanation is that the dense air mass rests on an even denser column, a hypothesis, in any case, that it should come accompanied by horizontal or even vortex-shaped winds.
Images | NASA