Swarm: ESA’s magnetic field mission

Swarm facts and figures

The Swarm mission was designed to measure the magnetic signals that stem from Earth’s core, mantle, crust, oceans, ionosphere and magnetosphere. This will lead to better understanding of the processes that drive Earth’s dynamo, which currently appears to be weakening. By studying the complexities of Earth’s protective shield, Swarm will provide a clear insight into processes occurring inside the planet. Along with measurements of conditions in the upper atmosphere, a better knowledge of the near-Earth environment and the Sun’s influence on the planet can be realised.

Mission
Launched: 22 November 2013
Duration: 4 years (following 3-month commissioning phase)

Objectives
A unique view inside Earth to study:

- Core dynamics, geodynamo processes and core-mantle interaction
- Magnetism of the lithosphere and its geological context
- 3D electrical conductivity related to mantle composition

To study the Sun's influence on the Earth system by:

- Analysing electric currents in the magnetosphere and ionosphere
- Understanding the impact of solar wind on the dynamics of the upper atmosphere

Orbit
Type: Low Earth; near-polar
Configuration: constellation of three identical satellites: two orbit side-by-side, decaying naturally from an initial altitude of 460 km to 300 km over 4 years; the third maintains an altitude of about 530 km. The initial inclination difference of 0.6° between the lower pair and the higher satellite ensures a 90° difference in orbital plane in the third year of operations.

Payload
Vector Field Magnetometer, Absolute Scalar Magnetometer, Electric Field Instrument, Accelerometer, GPS receiver, startrackers and laser retroreflector

Configuration
Three identical satellites, 9.1 m long (including a 4-m deployable boom), 1.5 m wide and 0.85 m high

Mass
Each satellite weighs 472 kg at launch, including 106 kg of Freon propellant

Power
GaAs solar cells, 48 AH Li-ion batteries
Consumption: instruments 50 W; platform units 140 W

Attitude Control
3-axis stabilised, Earth-oriented
Startrackers, magnetometers, magnetotorquers
Cold-gas (Freon) propulsion: 20 mN thrusters for attitude control and 50 mN thrusters for orbit control

Command and Control
Integrated data handling and Attitude and Orbit Control System computer with communication via a 1533 bus and serial links

Onboard Storage
2×16 Gbit solid-state mass memory unit
Payload data generated on board: 1.8 Gbit/day

Communication Links
Once per day to ground station at Kiruna (SE) S-band (2 GHz): 6 Mbit/s downlink; 4 kbit/s uplink rate

Flight Operations
Mission control from ESA’s European Space Operations Centre, ESOC, in Darmstadt (DE), via ground stations in Kiruna (SE)

Data Processing
Science data downloaded to the Kiruna ground station Data processing, distribution and archiving managed by ESA’s Centre for Earth Observation, ESRIN, in Frascati (IT)

Project
Mission development and commissioning managed at ESA’s European Space Research and Technology Centre, ESTEC, in Noordwijk (NL)

Launch Vehicle
Rockot (with Breeze-KM upper stage) from Plesetsk (RU), provided by Eurockot Launch Services GmbH (DE). The constellation is launched on one rocket and injected into orbit simultaneously at 490 km and 87.55°

Prime Contractor
Astrium GmbH, Friedrichshafen (DE)


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