Satellite Triplets Map Out Earth’s Magnetic Field

The three Swarm satellites are scientists’ most important tools to understand the magnetic field. The satellites have already made major discoveries.

The Swarm constellation consists of the Alpha, Bravo, and Charlie satellites, which cooperate to measure the strength and direction of Earth’s magnetic field. The collaboration makes the measurements 10 times more accurate than with one satellite. After only a few years in space, Swarm has supplied data for several ground-breaking scientific discoveries, of which the major one is an increasing river of liquid iron in Earth’s outer core below Alaska and Siberia. Moreover, Swarm has found out how bad weather in Earth’s upper atmosphere causes GPS network errors and blackouts. In April 2017, the satellites discovered a flow of 3,000 °C gases 300 km above Earth’s surface.