CEA-Leti's next-generation magnetometer technology was launched into space on board the European Space Agency's three Swarm satellites to collect unprecedented detail about the Earth's magnetic field.

The four-year mission will gather data that for the first time will make it possible to distinguish between the various sources of the magnetic field: the Earth's core, mantle, crust and oceans, as well as the ionosphere and magnetosphere.

These high-precision and high-resolution measurements will improve scientists' understanding of the Earth's magnetic-field structure, evolution and interaction with the solar wind. Scientists hope the data also will shed light on why the magnetic field, which shields the Earth from cosmic radiation and harmful charged particles in the solar wind, is weakening.

The three identical satellites, which were lifted into orbit by a Russian Rockot launcher, will be positioned so as to simultaneously acquire measurements in three different locations and time zones. They are carrying three measuring instruments that will directly contribute to the magnetic field studies:

+ a vector magnetometer to measure the components of the magnetic field in space

+ a stellar camera giving the orientation of the vector magnetometer in space, and

+ a Leti-designed absolute scalar magnetometer (ASM) for measuring the intensity of the field without drift or bias, i.e. without systematic error, and with unmatched precision and resolution. The ASM's ability, unique in the world, to simultaneously measure the direction of the field will also be implemented in an experimental mode.

When they reach their orbiting positions 450 and 530 kilometers above Earth, the satellites will provide simultaneous measurements from three different positions at different local times.

To prevent interference in the highly sensitive measurements by the crafts themselves, Leti's absolute scalar magnetometers will be deployed at the very tip of booms extending nine meters from the rear of each satellite platform.

"The Swarm mission's three absolute scalar magnetometers, which underscore Leti's advanced sensor design-and-performance capabilities, provide the mission with critical technologies for understanding past, present and future dynamics of the magnetic field," said Laurent Malier, CEO of Leti.

"This is a tribute to the technological excellence that characterizes Leti's divisions and to our commitment to collaborate with French and European technology partners."

"We developed an architecture that is free of the orientation effects common to all standard scalar magnetometers based on magnetic resonance to take full advantage of the ASM's performance" said Jean-Michel Leger, manager of Leti's Space Applications Program.

"These instruments represent the latest and most effective technology available to measure key characteristics of the magnetic field."

Developed from conception to space readiness with technical and financial assistance from CNES and scientific support from IPGP, the Leti magnetometers are Leti's third contribution to studying the magnetic field from space.

Nuclear magnetic resonance (NMS) magnetometers, designed and developed with CNES support, were part of the 1999 Oersted and 2000 Champ missions. Designed for a 14-month data-gathering mission, the Oersted satellite is still sending data back to Earth.

CNES-IPGP researchers will be in charge of scientific validation of the data provided by the absolute scalar magnetometers.

The magnetic field models resulting from the Swarm mission also will further scientists' understanding of atmospheric processes related to climate and weather, will help improve the accuracy of navigation systems and will have practical applications in many different areas, such as space weather.