Oersted satellite

Ørsted, the first Danish satellite, carried five science instruments with the objective of mapping the Earth's magnetic field and measuring its associated high-energy charged particle environment. Data from the mission was used to improve geomagnetic models, study the auroral phenomena, and complements data taken by the Magsat spacecraft in the late 70's-early 80's.

Ørsted was gravity gradient stabilized using a deployable 8 meter instrument boom. Magnetic torque coils maintained yaw to within 10 degrees. Attitude determination was via a star camera, with sun sensors and magnetometers as backup. 5 body mounted solar panels with GaAs cells provided 54 watts average power (EOL). NiCd batteries provided power in eclipse. Position determination was provided with GPS receivers: a single-band 6-channel TANS receiver from Trimble, and a dual-band 8-channel GPS TurboRogue from JPL, with a resolution of 50 meters or better. Command and control was via two 80C186 processors. On-board storage of 13 hours of science data was possible. The S-Band communications with a maximum data rate of 256 kbps used cross-dipole antennas.

The Overhauser proton-precession magnetometer measured the scalar values of the magnetic field with a resolution of < 1 nT. A CSC fluxgate magnetometer measured the vector values of the magnetic field with a resolution of < 3-5 nT. Six particle detectors measured high-energy charged particles: electrons (30 KeV to 1 MeV), protons (200 KeV to 30 MeV), and alpha-particles (1 to 100 MeV). The Star Imager determined the absolute attitude of the CSC fluxgate magnetometer with a resolution of < 20 arc-seconds. A GPS TurboRogue dual frequency receiver, with a position accuracy of 5-10 cm, allowed occultation measurements to determine temperature and electron density properties. The two magnetometers and the star imager were placed on an 8 meter deployable boom. The particle detectors and the GPS TurboRogue were mounted on the main spacecraft.

The spacecraft was named after the Danish physicist Hans Christian Ørsted who discovered electromagnetism in 1820.

Design Life: 1 year (3 year goal). Typical orbit: 450 x 850 km, elliptical, polar. Length: 8.00 m (26.20 ft). Maximum Diameter: 0.45 m (1.47 ft). Mass: 62 kg (136 lb).

• 1999 February 23 - Orsted - Launch Site: Vandenberg. Launch Complex: SLC2W. Launch Vehicle: Delta. Mass: 62 kg (136 lb). Perigee: 644 km (400 mi). Apogee: 863 km (536 mi). Inclination: 96.50 deg.
  Denmark's Orsted gravity gradient stabilised satellite was to map the Earth's magnetic field. It was managed and operated by the Danish Meteorological Institute in Copenhagen. The satellite's prime contractor was CRI , Copenhagen.