Ørsted (satellite)

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Oersted satellite model.jpg
Model of the Ørsted Satellite in the Tycho Brahe Planetarium
Organization Danish Meteorological Institute
Contractor Computer Resources International
Mission Type Earth Observation
Satellite of Earth
Launch February 23, 1999 on Delta II 7920
Launch site Vandenberg AFB SLC-2W
Mission duration 15 years, 9 months and 26 days
Mass 61 kg (launch), 50 kg (dry)
Webpage web.dmi.dk/fsweb/projects/oersted/
Semi-major axis 7,118.29 kilometres (4,423.10 mi)
Excentricity 0.0142
Orbital inclination 96.4798°
Apoapsis 865 kilometres (537 mi)
Periapsis 649 kilometres (403 mi)
Orbital period 100.0 minutes
Right ascension of the ascending node 106.5°
Argument of perigee 278.37°
Power 54.0 watts

Ørsted is Denmark's first satellite, named after Hans Christian Ørsted (1777–1851) a Danish physicist and professor at the University of Copenhagen. It is in an almost sun synchronous Low Earth orbit.

After more than ten years in orbit, the Ørsted satellite is still operational, and continues to downlink accurate measurements of the Earth's magnetic field. Ørsted was constructed by a team of Danish space companies, of which CRI was prime contractor. CRI was acquired by Terma A/S before Ørsted was launched, and the daily operations are being run as a teamwork between Terma A/S and the Danish Meteorological Institute.

In 2010, Ørsted passed within 500 meters of debris from the 2009 satellite collision but suffered no damage.[1]

Ørsted was the first in a planned sequence of microsatellites to be flown under the now discontinued Danish Small Satellite Programme.

Mission Objectives[edit]

The main scientific objective of the spacecraft was to map the Earth's magnetic field and collect data to determine the changes occurring in the field.

Based on data from the Ørsted satellite, researchers from Danish Space Research Institute concluded that the Earth's magnetic poles are moving, and that the speed with which they are moving has been increasing for the past few years. This apparent acceleration indicates, that the poles of the Earth might be in the process of switching around, which could have serious consequences for land-based biological life.

The results have been published in several prominent scientific journals, and graced the cover pages of Geophysical Research Letters,[2] Nature,[3] and Eos.[4]


The primary scientific instruments on the Ørsted satellite are:

  1. An Overhauser magnetometer provides extremely accurate measurements of the strength of the magnetic field. The Overhauser magnetometer is situated at the end of an 8 meter long boom, in order to minimize disturbances from the satellite's electrical systems.
  2. A CSC fluxgate vector magnetometer, used to measure the strength and direction of the magnetic field. The CSC magnetometer is situated somewhat closer to the satellite body in the so-called "gondola", together with the
  3. A Star Imager, used to determine the orientation of both the satellite and the CSC magnetometer.

The other three instruments are located in the main body of the satellite:

  1. A Charged Particle Detector, used to measure the flux of fast electrons, protons and alpha particles around the satellite.
  2. A BlackJack GPS Receiver, developed by the NASA Jet Propulsion Laboratory and used to accurately determine the satellite's position; can also be used to monitor the atmospheric pressure, temperature and humidity profile on the path between Ørsted and GPS satellites through atmospheric occultation.[5]
  3. A Trimble TANS GPS Receiver, also used to determine the satellite's position as a backup to the BlackJack.

See also[edit]


  1. ^ terma.com
  2. ^ Purucker, M., Langlais, B., Olsen, N., Hulot, G. & Mandea, M.: The southern edge of cratonic North America: Evidence from new satellite magnetometer observations, Geophys.Res.Lett., 29(15), 8000, doi:10.1029/2001GL013645, 2002 [part of a special issue on results from the Ørsted satellite. Plate 3 from this paper is the cover of a special Ørsted issue on August 1, 2002 (Issue #15).]
  3. ^ Hulot, G., Eymin, C., Langlais, B., Mandea, M. & Olsen, N.: Small-scale structure of the geodynamo inferred from Oersted and Magsat satellite data, Nature, Volume 416, Issue 6881, pp. 620-623 (April 2002)
  4. ^ Neubert, T., Mandea, M., Hulot, G., von Frese, R., Primdahl, F., Jørgensen, J.L., Friis-Christensen, E., Stauning, P., Olsen, N. & Risbo, T.: Ørsted Satellite Captures High-Precision Geomagnetic Field Data, EOS, Vol. 82, No. 7, p. 81, 87, and 88, Feb. 13, 2001
  5. ^ Montenbruck, O; Garcia-Fernandez, M; Williams, J (2006). "Performance comparison of semicodeless GPS receivers for LEO satellites". GPS Solutions (Springer-Verlag) 10 (4): 249–261. doi:10.1007/s10291-006-0025-9. Retrieved 2014-04-15.