Satellites, sounding rockets or balloons use the Earth’s magnetic field as a reference to determine their, and by extension their payload, orientation. Knowing which orientation, the instruments on board or the craft is in is essential.
Satellites, from small CubeSat to larger platforms, will likely have a magnetometer on board used typically for attitude control. It is also typical, once installed, to perform system checks to account for distortion caused by the rest of the satellite.
Using one of the Helmholtz Coil systems (typically 1m or larger), a precise field can be generated around the satellite and determine accuracy of the on-board magnetometer.
Magnetic Field Mapping
Magnetometers on board satellites or balloons are also used to perform magnetic field surveys used to study the Earths’ magnetic field.
Satellite Magnetic Hygiene
In some cases, spacecraft are going to be extremely sensitive to exposure to magnetic fields, or it is going to be critical that the signature of the satellite is kept to a minimum. Fluxgate magnetometers or hall probes can be used to monitor either field exposure or measure signature of components.