Heritage

Since the first studies for Star Trackers, SODERN has gained extensive experience in this field of spacecraft attitude measurements. Four successive generations of Star Trackers have been developed featuring key technologies:

SED03/SED04
IDT, Small Field of View (FoV),
Non autonomous, 15 kg, 40 W

• Image Dissector Tube IDT Star Trackers (SED03/SED04),
• Charge Coupled Device CCD Star Trackers (SED12/12D),
• Autonomous CCD Star Trackers (SED16/26/36).
• Autonomous Active Pixel Sensor (APS) Star Trackers (HYDRA)

The SODERN experience in Star Trackers started in the 70s with the development of the first European Star Trackers SED03 and SED04 for the EXOSAT satellite and for the IPS (Instrument Pointing System) of the Space Shuttle. Both systems have been successfully flight proven, in 1983 and 1985 respectively.

SED12/SED12D
CCD (360x280 pixels), Medium FoV,
Non autonomous, 8 kg, 20 W

SED16/SED26/SED36
CCD (1024x1024 pixels), Large FoV,
Fully Autonomous, 3 kg, 10 W

In 1985, SODERN started to develop the first CCD based Star Tracker in Europe: the SED12, developed for the French-Russian experiment “Sigma” placed on the Russian satellite “Granat”. The satellite was launched in 1989 and the SED12 operated perfectly for ten years, until the satellite was retrieved from service, three times later than the designated lifetime. Another version of the sensor, called SED12D, was developed for the Helios satellites (French MoD Earth Observation satellites), and also used on the ODIN (Swedish experiment) and ENVISAT satellites. As of April 2011, they have totalled more than 800 000 hours of successful operating hours in orbit.

At the end of the 90s, SODERN developed an Autonomous Star Tracker product line based on a 1k x 1k CCD: the SED16/26/36 family. The SED16 was flight qualified on the SPOT5 satellite in May 2002, and it is currently still in operation with its nominal performance. As for April 2011, there are more than 70 in flight SED16/26/36 perfectly operating and totalling more than 2 000 000 in flight operating hours. More than160 SED16/26/36 have been ordered by more than fifteen different end users, in ten different countries around the world.

SODERN has recently developed a new Star Tracker product line, based on APS detector, the Multiple Head Star Sensor HYDRA. This very robust Star Tracker will pave the way for gyroless and single sensor AOCS architecture. It has been fully on-ground qualified in 2010.