Servo Corporation of America - All rights reservedDual Array Single Head Earth Sensor (DASH)The DASH unit is currently flying on the TOPSAT satellite (Figure 1). TopSat was built by Surrey Satellite Technology, LTD for the UK Ministry of Defence and the British National Space Center and launched into orbit in October 2005. It has since become one of SSTL’s premier imaging satellites claiming the best resolution of per mass of any imaging satellite. The DASH is the primary attitude determination device on this satellite. A similar set of sensors were built and delivered to the Canadian Space Agency but have not been launched. A variation of the DASH unit but with only one sensing element is under production for the Orbcomm Program with a total of 38 units being delivered.