One option was to bring them down. And Iridium Satellite LLC will make data available for scientific study. The important aspect for our research, said Dr Waters, is that each satellite has a magnetometer, which measures Earth s magnetic field. Its magnetic field interacts with the solar wind and the interplanetary magnetic field, forming a complex and violent region called Geospace. Much remains unknown about Geospace and space weather, but magnetometers are one key to learning more.
Magnetometers measure variations in magnetic field strength.
When used to study Earth s magnetic field, the magnetometer variations can be interpreted to show Geospace dynamics, ie. They also allow comparison with ground stations, to study magnetic wave propagation. The magnetometers, while far less sensitive than FedSat s, provide the advantage of many data points, instead of just one for FedSat. So the Iridium network provides 72 simultaneous magnetometer measurements all around Geospace. Never before has it been possible to view magnetic activity for the whole globe at once.