Reception and processing of satellite data
Satellite operations at Esrange began in 1978 when the receiving station was set up for the American remote sensing satellite Landsat. Since then, satellite operations have grown considerably, and today comprise control of and data reception from Swedish and international satellites. In addition to remote sensing (satellite imagery) the operations include satellites for tele-communications and space science.
Satellites that orbit the earth from pole to pole are called polar satellites. They pass within Esrange coverage area on 12 out of every 14 orbits, thanks to our northerly location. The satellites are often in orbit at an altitude of 600-800 km and are equipped with instruments trained on the earth to take satellite images.
They can also be scientific satellites, placed in an elliptical orbit. The maximum altitude is then considerably greater, thereby permitting measurements further out in space.
Another type of satellite orbits at 36,000 km above the equator, at 90º to the polar orbits. This altitude means that the orbital time around the earth is 24 hours, and since the earth also completes one revolution on its axis at the same angular velocity, the satellite is therefore perceived to remain motionless in the sky. The satellites are suitable above all for telecom, since we are in constant contact with them.