Signal Carrier

The Air Force has received the last of eight modernized Global Positioning System Block IIR satellites from Lockheed Martin and is preparing to launch this satellite into orbit on June 30. Although this satellite, which is designated GPS IIR(M)-20, is the last of the eight Block IIR-M satellites to be delivered, it will be the seventh to go into orbit. GPS IIR(M)-21, already in USAF possession, will not be carried into space until a mission in September. Like all eight Block IIR-M satellites, GPS IIR(M)-20 carries the L2C civilian signal and M-code military signal. Unlike the other in the series, it will also transmit on a civil frequency called L5, which is primarily designed for aviation safety-of-life applications. (Schriever report by SSgt. Don Branum)