Freja is a joint Swedish and German scientific satellite project to study the interaction between hot magnetospheric plasma and the topside atmosphere/ionosphere. This interaction leads to a strong energization of magnetospheric and ionospheric plasma and an associated erosion and loss of matter from the terrestrial atmosphere. Using novel plasma instruments and a high data rate Freja have provided a number of ''firsts'' in high resolution plasma diagnostics from satellites. Freja's high spatial/temporal resolution permits studies of meso- and microscale phenomena in the 100-m range for particles and in the 10-m range for electric and magnetic fields.

The Freja satellite was successfully launched on October 6, 1992 into an orbit with 63¿ inclination, an apogee of 1750 km and perigee of 600 km. ¿ American Geophysical Union 1994