ASTRO APS is an autonomous star sensor with the most advanced radiation hard CMOS Active Pixel Sensor (APS) detector technology.

A single box design has been chosen with minimized dimensions, low mass and low power consumption while maximizing the ease of integration on the spacecraft. ASTRO APS shows high reliability and radiation hardness by careful selection of EEE Parts, reduced number of components and special software algorithms to cope with radiation events.

The technical key parameters of the APS based star sensor are the low mass budget with approx. 2kg, the low power consumption with approx. 5W and the attitude quaternion accuracy of <1arcsec (1sigma). These data define a new level of compactness compared to CCD-based star sensors for the GEO telecom market (>18 years life time, <25 years radiation robustness for GEO missions).

The improvements in dimensions and performance are realized with the replacement of the CCD detector by the APS detector technology. The mass and envelope benefit is based on the very high functional integration of the APS detectors. The whole analogue read-out and sampling electronics is placed on the detector chip. This saves PCB area compared to CCD-based systems. The parts count for an APS based star sensor is reduced accordingly. Along with that, the unit costs are reduced and the system reliability is increased.