internationally recognized research environment in the field of solar-terrestrial physics, a Solar-Terrestrial Physics Laboratory, comprising magnetospheric, ionospheric, and atmospheric physics in combination with research in the magnetic field of the Earth. Correlative studies will be carried out using observations from existing monitoring stations in Greenland and other polar regions. Mission The spacecraft was launched, on 23 February 1999 at 10:29:55 UTC, by a Delta II rocket, from the Vandenberg Air Force Base SLC-2W pad, as an auxiliary payload (primary payload was ARGOS and another auxiliary payload was SUNSAT; the auxiliary payload satellites were launched free of charge) into a near-sun synchronous elliptical polar orbit, it had a perigee of , an apogee of , an inclination of 96.1, and an orbital period of 100.0 minutes, and nodal drift rate 0.76°/day. It is gravity-gradient stabilized, with its extendable boom aligned to and pointing away from the center of the Earth. Active attitude control is achieved using three-axis magnetic torquing coils. The data system features onboard monitoring and pre-processing. Data is stored in a 16 Mbyte on-board memory and downlinked in a packetized format when a ground station is in view. In 2010, Ørsted passed within 500 meters of debris from the 2009 satellite collision but suffered no damage. Based on data from the Ørsted satellite, researchers from the 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 Earth's magnetic field might be in the process of reversing, which could have serious consequences for land-based biological life. The results have been published in several prominent scientific journals, and printed on the cover pages of Geophysical Research Letters, Nature, and Eos. Ørsted was the first in a planned sequence of microsatellites to be flown under the now discontinued Danish Small Satellite Programme. After more than twenty years in orbit, the Ørsted satellite is still operational (as of 2023), 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 run jointly by Terma A/S and the Danish Meteorological Institute. See also Swarm (ESA mission) Magsat References Science and technology in Denmark Geomagnetic satellites Spacecraft launched in