The three identical satellites that form the Swarm constellation were launched from the Russian Plesetsk cosmodrome using a Rokot rocket. Their purpose is to study the Earth’s magnetic field. The satellites have been successfully put into orbit and after about one hour and a half communications have been established with all the three of them.
While NASA’s van Allen mission that started last year, originally known as the Radiation Belt Storm Probes (RBSP), aims to study the Van Allen belts, the Swarm mission is more focused on the analysis of the electromagnetic activity occurring within the Earth, at its core, mantle, crust and oceans. The search is complete so the activity in the ionosphere and magnetosphere will also be analyzed.
The purpose of the Swarm mission is to better understand the processes that make the Earth work like a dynamo, an activity which at the moment seems to be weakening. In common with the mission of the van Allen spacecraft there’s the part of the research that has as its purpose the analysis of the influence of solar flares on the upper Earth’s atmosphere.
Once they get into low earth orbit, the three satellites started to separate to reach the final trajectories with a series of maneuvers that will go on for months due to the low power of their engines. Two satellites will travel in parallel trajectories starting at a height of about 460 km (about 285 miles) which will come in time down to about 300 km (about 185 miles). Instead, the third satellite will go up at an altitude of about 530 km (about 330 miles) on a trajectory that will eventually be orthogonal to that of the other two.
The three satellites are equipped with various instruments able to measure with great accuracy a quantity of electromagnetic emissions. The main instrument, called Vector Field Magnetometer (VMF), is mounted on a long boom which will be deployed in the next few hours, after the system check-ups. The use of a boom is necessary to avoid the detections from being disturbed by the electromagnetic emissions of the satellites themselves.
The instruments of the Swarm satellites also include an accelerometer that provides measurements about the air drag and the effects of the solar wind. Its findings will be used in conjunction with the electromagnetic ones to improve our understanding of the influence of the solar wind on the atmosphere.
The mission of the Swarm satellites should last at least 4 years during which data will be collected that will help create more accurate global models of the magnetic field generated by the Earth’s core and the crust and of its evolution.