Low-Earth orbit (LEO) satellites provide unique opportunities to characterize the Earth's magnetic field, ionospheric currents and plasma parameters, and thermospheric density and winds across a wide spectrum of time and spatial scales, and for a large range of solar and geomagnetic activities.
At the forefront of this advance are the three ESA Earth Explorer Swarm satellites, which have been providing high-accuracy measurements of the Earth's magnetic field, electric field, plasma parameters, precise-orbit determination, and accelerometer
observations since their launch in November 2013. They have proven very valuable for studying the near-Earth magnetic field and the coupled ionospheric-thermospheric environment, and enabled the development and implementation of advanced models and operational space weather services. The scientific potential of the polar-orbiting Swarm satellites is today augmented by newly available data, especially those collected by the low-inclination Macau Science Satellite 1 and CSES satellites.
In addition, the ESA Scout NanoMagSat constellation, consisting of one
near-polar and two 60° inclination satellites, is scheduled to launch near the end of 2027, with full operation planned for 2028. It will acquire high-accuracy magnetic vector and scalar data, electron density, and electron temperature
data, navigation data, and collect ionospheric radio-occultation profiles. All these data are also complemented by increasingly available platform-magnetometer data, such as from the CryoSat-2, GRACE, GRACE-FO, GOCE, and E-POP satellites. The new abundance of satellite data provides unprecedented space-time data coverage at LEO satellite altitudes, opening the way for new scientific opportunities.