Swarm (spacecraft)

Artist's impression of Swarm satellites

Artist's impression of the Swarm A and B.

Swarm is a European Space Agency mission, launched in 2013, which consists of three identical satellites designed to study Earth's magnetic field in greater detail than ever before. Swarm builds on the observations made by the earlier Oersted and CHAMP missions.

Two of the Swarm satellites fly side by side in a polar orbit with an altitude of 450 km (280 mi); the third moves in a different polar orbit with an altitude of 530 km (330 mi).


The high-precision, high-resolution measurements of the strength, direction, and variations of Earth's magnetic field made by the satellites will be used, among other things, to shed light on the dynamics of Earth's core, interactions between the core and the mantle, magnetization of the lithosphere, currents flowing in the magnetosphere and ionosphere, and ocean circulation (using its magnetic signature).


Instrument payload

Each spacecraft carries the following instruments:


  • Vector Field Magnetometer (VFM): Linear and low-noise measurements of the Earth's magnetic field vector components.
  • Absolute Scalar Magnetometer (ASM): Calibration of the main instrument VFM.
  • Electric Field Instrument (EFI): Measurement of ion density, drift velocity and electric field.
  • Accelerometer (ACC): Measurement of non-gravitational accelerations like air-drag, winds, Earth albedo and solar radiation pressure.
  • Laser Range Reflector (LRR): Reflecting quartz prisms as part of the satellite laser ranging network.

    launch date Nov 22, 2013
    Launch vehicle Rokot/Briz-KM
    Launch site Pletesk
    orbits Swarm A, B: polar, 460 km (apogee) × 87.4°
    Swarm C: polar, 530 km (apogee) × 88°
    dimensions 9.1 m × 1.5 m × 0.85 m
    mass 468 kg (launch); 369 kg (dry)