The ST400-T from AAC Clyde Space is a Star Tracker that is developed for microsatellite systems. This star tracker has an attitude determination accuracy of 10 arcseconds (pitch, yaw) and 120 arcseconds (roll). It has an update rate of 5 Hz and a maximum slew rate of 0.5 degrees/sec (tip/tilt) and 1 degree/sec (roll). The star tracker supports RS422/RS485 interface which allows for networking with multiple ST400’s and the components have a radiation tolerance of up to 9 krad (Si). It requires a DC supply of 3.6-34 V and has a power consumption of up to 1000 mW. The star tracker has a mass of 280 gms and measures 53.8 x 53.8 x 90.5 mm. It is ideal for attitude determination in small satellites and is aimed at applications in pico- and nano-satellite platforms.