Swarm three satellites to study the Earth's magnetic field

 

The Swarm mission and its three satellites will be launched next week by Europe from space to study the Earth’s magnetic field, a complex and fluctuating phenomenon that remains poorly known 2,000 years after the invention of the compass in China.

If the gravitational field is visible using a simple apple, “the Earth’s magnetic field, it, we do not see. Yet it is all around us, everywhere, and in particular protects us from the solar wind” and its particles explains Mioara Mandea, expert CNES, the French space agency, associated Swarm project.

The main source of the magnetic field of the Earth is located 3000 km under our feet, in the core of iron and nickel fusion that works like a giant dynamo currents through the cross.

But this magnetism addition of Other much smaller sources, such as magnetized rocks of the crust, as well as external sources such as the part of the atmosphere electrically excited by radiation from the Sun (ionosphere and magnetosphere) says Gauthier Hulot (CNRS / Institute of Earth Physics of Paris ).

“This is a very complex phenomenon that varies in space and time. It is well known that there are different sources, but in a given surface point everything is mixed,” summarizes Ms. Mandea.

This is why the European Space Agency (ESA) has chosen for the Swarm mission (“swarm” in English), an innovative configuration: three strictly identical satellites, false air of vessels in the Star Wars for aerodynamic performance suitable for low orbit.

Weighing 470 kg each, three Swarm satellites to be launched on Friday by a Rockot rocket from the Plesetsk base in Russia.

Space triplets evolve on slightly different trajectories (two 460 km initially, the third 530 km at the beginning of mission), which will separate the different magnetic sources and detailed mapping variations, not only in space but also in time.

Anomaly Atlantic South

To ensure greater accuracy in measurements, the researchers treated the particular “magnetic cleanliness” satellites, focusing on the most neutral possible. material

magnetometers shipped Swarm will be kept well away from the body satellites and their electromagnetic interference by deployable masts four meters long, says Isabelle Fratter, who led the CNES project magnetometer “absolute” ASM.

This instrument of unprecedented accuracy designed by CEA-Leti Grenoble measures the intensity of the magnetic field and will periodically calibrate other magnetometers called “vector” which, themselves, measure the orientation of the magnetic field in all three directions.

Through the data collected by Swarm for at least four years, scientists hope to better understand the evolution of the magnetic field, especially the “South Atlantic anomaly”: an area over Brazil where it is particularly low and continues to decline rapidly, for unexplained reasons.

Flying over this “Bermuda Triangle” where the natural magnetic shield of the Earth is weakened, satellites may experience malfunctions, and even the ground we get more particles from space.

“Understanding the evolution of the Earth’s magnetic field is how one can predict the future and identify possible protective measures, “said Hulot.

Swarm the raw data will also be used in maps and models supplying many everyday applications, such as maps of Civil Aviation or compasses smartphones, says the researcher.

Mapping all the more important that the compass does not indicate true north but the magnetic north, which moves very quickly?

Swarm three satellites to study the Earth's magnetic field