Freja is designed to image the aurora and measure particles and fields in the upper ionosphere and lower magnetosphere. The mission continues the investigations begun by its predecessor Viking. Freja was initiated in 1987 when a low-cost launch reservation on a Long March rocket for a small store-and-forward low-orbit communications satellite was cancelled. The total cost of the program through 2 years of operations, excluding instruments, was $19 million. The project was jointly financed by Sweden and the Federal Republic of Germany. It made high resolution measurements in the upper ionosphere and lower magnetosphere. Data received at Esrange, Kiruna, Sweden and at the Prince Albert Satellite Station in Canada's Saskatchewan Province. Spacecraft: Magnesium structure.3-axis magnetometer, sun sensors, IR earth sensor provide 0.5 deg. attitude knowledge. Spin stabilised, sun-pointing attitude maintained by magnetorquers. Annular solar arrays provide 130W, NiCd batteries.2W S-band transmitter downlinks at 256 kbps to 9 m dish. UHF uplink. The satellite was a prototype development effort. Payload: Payload mass 60 kg, uses 81 W. Six radial wire booms (1-15 m) and two stiff radial booms (1-2 m) used by experiments. Experiments include F1 - Electric Fields (Royal Inst. of Technology, Sweden); F2 - Magnetic Fields (APL/JHU); F3C - Cold Plasma (NRC, Canada); F3H - Hot Plasma (Swedish Inst. of Space Physics; F4 - Waves (Swedish Inst. of Space Physics; F5 - Auroral Imager (Univ. of Calgary); F6 - Electron Beam (Max-Planck Inst. ); F7 - Particle Correlator (Max-Planck Inst. )

Design Life: 2 years. Total Length: 1.7 m. Maximum Diameter: 2.2 m. Total Mass: 259 kg.

Ionospheric, auroral, amgnetospheric studies. Freja is a Swedish/German satellite designed for research into the aurora. The satellite was launched piggyback on a Long March 2C (CZ-2C) rocket and weighs 214 kg in orbit. It is a sun-pointing spinner (10 rpm) with a 2.2 m diameter. It will make high re solution measurements in the upper ionosphere and lower magnetosphere. Data will be received at Esrange, Kiruna, Sweden and at the Prince Albert Satellite Station in Canada's Saskatchewan Province. Launch time 0620 UT.

• 2 - McDowell, Jonathan, The United Nations Registry of Space Objects, Harvard University, 1997. HTML when accessed: http://hea-www.harvard.edu/QEDT/jcm/space/un/un.html
• 6 - JPL Mission and Spacecraft Library, Jet Propulsion Laboratory, 1997. HTML when accessed: http://msl.jpl.nasa.gov/home.html
• 279 - McDowell, Jonathan, Launch Log, October 1998. HTML when accessed: http://hea-www.harvard.edu/~jcm/space/log/launch.html