A novel geomagnetic satellite constellation: Science and applications

The European Space Agency (ESA)’s Swarm constellation of a trio of geomagnetic survey satellites in nearly circular polar orbits at altitude about500km was launched on 22 November 2013 and has been mapping the Earth’s global magnetic field in unprecedented details, helping scientists better understand how the geomagnetic field is generated and maintained inside the Earth’s fluid core and how the Earth’s external magnetic environment is changing. This review discusses a new novel constellation of the geomagnetic survey satellites that consists of at least four satellites: two satellites are in lower-latitude and nearly circular orbits at altitude about450km; two further satellites are marked by nearly polar but strongly eccentric orbits with perigee about200km and apogee about5000km. The new geomagnetic satellites are equipped with highly stable optical benches, high-precision fluxgate magnetometers and scalar magnetometers which are capable of mapping the Earth’s three-dimensional magnetic field in unprecedented accuracies and details. The new constellation will help elucidate different contributions to the measured geomagnetic field: the core dynamo field, the lithospheric magnetic field, the magnetic fields produced by currents in the ionosphere and the magnetosphere as well as by the currents coupling the ionosphere and magnetosphere, and the magnetic fields induced from the electrically conducting mantle, lithosphere and oceans. In comparison to the Swarm mission, it will provide higher-accuracy, higher-resolution and higher-dimension measurements of the geomagnetic field required for shedding new insights into the core dynamo processes and the Earth’s space magnetic systems along with a wide range of important applications.