Credits: ESA/B. Bergaglio
A three-headed startracker on one of ESA’s three Swarm satellites currently being prepared for launch, swathed in insulating material to prevent the temperature extremes in orbit knocking them out of alignment.
Startrackers are commonplace on satellites for navigation and attitude control, but this case they are an integral part of the magnetic mapping mission’s instrument package.
As Swarm’s Vector Field Magnetic Magnetometer measures the strength and direction of Earth’s magnetic field lines, this startracker provides a reference orientation.
Both instrument and startracker sit on an ultra-stable 'optical bench', maintaining an alignment of a single arcsecond – the diameter of a 10 cent coin seen from 4 km away.
Both were developed for the Swarm mission by the Technical University of Denmark.