Swarm satellites. Illustration of the three identical Swarm satellites from the European Space Agency deploying in Earth orbit. The satellites were launched together on one rocket on 22 November 2013. Named Alpha, Bravo and Charlie, they occupy different orbits (two in a lower orbit, one in a higher orbit) and record differences in the strength of the magnetic field associated with the Earth's core, mantle, crust, oceans, ionosphere and magnetosphere. This information is necessary for modelling the Earth's geomagnetic field, and its interaction with solar winds and with other physical processes such as ocean circulation, climate and weather. |