Stellar navigation

Scientists at DTU Space have developed a series of star trackers, which today are indispensable instruments onboard a number of European, US and asian spacecraft and instruments.

A star tracker enables satellites and space probes to orient themselves so scientists always know precisely which way the satellite is facing in space. Without this information, scientific measurements from satellites are often useless.

The star tacker comprises two main parts: a digital camera that photographs the night sky and a computer that matches the digital images against a stellar map stored in the computer. By comparing images of the dark sky with the stellar map, the star tracker is able to determine what direction it is pointing, and hence the orientation of the space probe to which it is attached.  




Facts about DTU Space's star trackers:
A star tracker is able to determine its direction in space with an uncertainty of as little as 1.5 arc seconds. This corresponds to us being able to see the top and bottom edge of a penny, seen edge-on, at a distance of 300 metres. 

The first DTU Space star tracker was originally developed for the Danish Ørsted satellite. It was tested for the first time in 1995 aboard a NASA probe called Thunderstorm, which tested new technologies for use in space. Since then, DTU Space has developed a series of star trackers that have become increasingly compact and sophisticated, and to date the instruments have flown on more than 30 international missions, including Juno, Swarm,  Astrid II, TeamSat, CHAMP, PROBA, GRACE nas TESS, with the prospect of many more to come.


John Leif Jørgensen
Professor and Head of Measurement and Instrumentation
DTU Space
+45 45 25 34 48