Case study


Earth’s magnetic field holds many mysteries and the Swarm mission aims to understand them.

Swarm mission.
Artist's impression of the Swarm mission. Credit: ESA.

The European Space Agency’s (ESA) Earth explorer Swarm mission sets out to improve our understanding of Earth’s magnetic field. Mission overview:

  • three identical satellites
  • launched in 2013

Swarm is the European Space Agency’s first constellation of Earth observation satellites and will be made up of three identical satellites, which are due to lift off together on a Rockot launcher from Plesetsk in northern Russia in 2013.

The mission sets out to improve our understanding of the Earth’s magnetic field, trying to find out how it is generated and how it changes over time. The Earth’s magnetic field is in a constant state of flux and, currently, shows signs of weakening. The magnetic field acts like a shield protecting the planet from charged particles that stream towards Earth in solar winds. Without it, life on Earth could not exist.

Swarm will be the fourth Earth Explorer satellite in orbit. ESA’s Earth Explorer satellites provide a unique approach to observing Earth from space. They have been developed in direct response to issues raised by the scientific community, to improve our understanding of how the ‘Earth system’ works and the effect that human activity is having on natural processes. Mission facts

ESA’s Swarm satellites are being subjected to an intense testing programme at IABG in Ottobrunn, Germany, in a forest, far from any other buildings to minimize any magnetic disturbance, to ensure that they will withstand the rigors of space.

The satellites will carry a new generation of magnetometers to identify and measure the magnetic signals that stem from the various sources with unprecedented accuracy. These advanced sensors will be mounted on the satellite’s 4 m-long arm to minimise interference from the electric units on the craft. Technology

Swarm is made up of a constellation of three satellites; two of which will orbit the Earth side-by-side, with the third satellite in another orbital plane at the higher altitude. The three satellites are identical in size and shape, each measuring about 9.25 meters in length and all carry the same instrument package.

A deployable arm makes up more than half of the length of the satellite and about half way along carries one of the main instruments – the so-called Vector Field Magnetometer. Apart from the long arm, which is deployed once in orbit, the satellite has no other moving parts. The solar panels are rigidly fixed to the satellite body forming a ‘roof’.

High-precision and high-resolution measurements of the strength, direction and variations of the Earth’s magnetic field, will provide valuable data, which is essential for modelling the geomagnetic field. The results will offer new insights into the Earth system by improving our understanding of the dynamics of the Earth’s core, the composition of the mantle and structure of the crust. Swarm will also enable analysis of the Sun’s influence on the Earth. UK involvement

Participants from the UK attended ESA’s Second International Science Meeting on the Swarm mission in June 2009 in Potsdam, Germany, which aimed to bring together scientists and students, working in all fields of geomagnetism and/or the near-Earth electromagnetic environment, who would benefit from the Swarm constellation.

For more detailed information on Swarm, visit ESA’s website.

Published 29 April 2014