GPS-35, -36
RetroReflector Array (RRA) Characteristics:
Courtesy of HTSI
In contrast to GLONASS, only two GPS satellites (-35 and -36) are equipped with a laser retroreflector arrays. The GPS retroreflector array was built by the Russian Institute for Space Device Engineering and is similar in design to those used on the GLONASS satellites. However, the total reflecting area is considerably smaller due to limited mounting space on the GPS satellites. Each retro-reflector is coated on the back reflective surfaces with aluminum. The GPS retroreflector array consists of 32 fused-quartz corner cubes arranged in a flat panel in alternating rows of either four of five cubes. The array measures 239 millimeters in length, 194 millimeters in width, and 37 millimeters in height and weighs 1.27 kilograms. At normal light incident angle, the aperature of an individual cube corner is a rectilinear hexagon equivalent in area to a circle 28.6 millimeters in diameter. (ref: Degnan, J.J., Pavlis, E.C., "Laser Ranging to GPS Satellites with Centimeter Accuracy", GPS World, Vol. 5, no. 9, pp. 62, 64, 66-68, 70. Sept. 1994).
