The Swarm mission is helping unravel one of the most mysterious aspects of our planet: its magnetic field.
The magnetic field and electric currents in and around Earth generate complex forces that have immeasurable impact on everyday life. The field protects us from cosmic radiation and charged particles that bombard Earth in solar winds. Although we know that the magnetic field originates from several places, exactly how it is generated and why it changes is not yet fully understood.
Swarm comprises a constellation of three satellites, named Alpha, Bravo and Charlie, initially orbiting in two different near-polar orbits at 460-km and 530-km altitudes. The Swarm Mission Operations Centre (MOC) is located at ESA's ESOC establishment in Darmstadt, Germany. The primary ground station is Kiruna, while the mission's Processing and Archiving Element, managed by ESA's ESRIN, oversees the generation of data products from the science data stream and interfaces with the scientific community.
The Flight Control Team operations the Swarm satellites from a Dedicated Control Room located at ESOC. From 2007-11, ESOC engineers and mission planners developed the overall ground control infrastructure, flight control procedures and interfaces with other teams. Specific training for the Flight Control Team began in 2012, and the months prior to launch in late 2013 were dedicated to intensive team training in a series of realistic simulations.
Mission operations overview
The three Swarm satellites were launched together on a Rockot launcher from Plesetsk, Russia.
In orbit, all operations are controlled from ESOC, while data processing and archiving is handled from ESRIN. The 15-m Estrack ground station at Kiruna is the mission's dedicated ground tracking station, while other stations provide support as needed.
Mission control system
For routine operations, the mission uses ESA's 15m Kiruna ground station – part of the Agency's Estrack global ground station network – for command, control and tracking of the three satellites. Kiruna provides daily visibility for the satellites in both the upper and lower Swarm orbits; the number of visible passes per day varies from nine (for the upper satellite, at beginning of mission), to six (for the lower pair, at the end of mission – when the orbit altitude will be as low as 300 km). For routine operations, one pass per day per satellite is sufficient to cover the monitoring and control needs. Tracking, Telemetry & Commanding (TT&C) communication is be done at S-band frequencies, providing an uplink of 4 kbps and a downlink of 6 Mbps.
The overall structure consists of the Bus Assembly, Solar Generator Assembly, Boom Assembly and Launch Adaptor.