On Friday, the European Space Agency (ESA) began a four-year mission to study the Earth’s magnetic field with the launch of the three-satellite Swarm constellation into Earth orbit. Packed “like sardines” in their fairing, the unmanned spacecraft lifted off at 12:02 GMT (1:02 PM CET) from the Plesetsk space port in northern Russia atop a Rockot launcher.

About 91 minutes after launch, which ESA says went off without incident, the three satellites automatically separated from the Breeze-KM upper stage and went into a near-polar circular orbit at an altitude of 490 km (300 mi). Two minutes after that, contact was made with the constellation as it flew over Kiruna station in Sweden and Svalbard station in Norway. Control of the satellites was switched to the European Space Operation Centre in Darmstadt, Germany and a few hours later the Swarm satellites deployed their instrument booms.

“Swarm is about to fill a gap in our view of the Earth system and in our monitoring of global change issues,” said Volker Liebig, ESA’s director for Earth observation. “It will help us to better understand the field that protects us from the particles and radiation coming from the Sun.”

According to ESA, the three satellites will go through a three-month commissioning as mission control tests their systems and scientific payloads. If they pass successfully, two of the constellation will fly in formation about 150 km (93 mi) apart and lower their orbit to 460 km (285 mi). Meanwhile, the third will move into a higher orbit of 530 km (330 mi). Together, they will take precise measurements of the Earth’s magnetic field.

Following the CryoSat, GOCE and SMOS satellites, Swarm is the fourth of ESA’s Earth Explorer missions, which are intended to help improve the understanding of our planet by focusing on the atmosphere, biosphere, hydrosphere, cryosphere and Earth's interior.

Scientists hope that the measurements of the magnetic field taken by the Swarm constellation will not only help them to produce better models of the field, but also improve terrestrial navigation and weather forecasting, aid in prospecting for mineral resources, reveal more about the Earth's interior structure and provide better warnings of dangerous solar storms.

The video below shows Swarm’s liftoff.

Source: ESA