Courier 1B was an experimental military communications satellite that could record messages from an Earth station and rebroadcast them. It was launched from Cape Canaveral and operated in Earth orbit for 17 days. Run by the U.S. Army Advanced Research Project Agency, Courier was a successor to the SCORE program. The objective of the mission was to put the satellite into a 1000 km (600 mile) altitude Earth orbit and test the feasibility of a global military communications network using "delayed repeater" satellites, which receive and store information until commanded to transmit. Spacecraft and Subsystems Courier 1B was a 225 kg (500 lb.), 129.5 cm (51 in.) diameter sphere, 135 kg (300 lb.) of this was the electronic equipment payload. It carried four 2-W microwave FM (1700-1800 MHz) tranmitters and a 50-mW transistorized VHF beacon transmitter subsystem. It contained four solid-state receivers in the 1800-1900 MHz microwave band. Five tape recorders were used to store data for later playback. Four of these were digital with a total capacity of 13.2 Mb (4 minutes at 55 kbps) each. One was an analog recorder with 4 minute capacity and a range of 300 to 50,000 Hz. Four whip antennas were mounted at 90 degree intervals along the equator of the sphere. It also held two microwave antennas, a transistorized telemetry generator, VHF diplexer, and a command decoder. The transmitters and receivers were set up so two of each would be running at any given time, the others were on standby and could be switched in by ground command. The sphere was covered with 19,200 solar cells, charging nickel-cadmium batteries, providing 60 W power. The satellite had the capability to simultaneously transmit, receive, and store approximately 68,000 coded words per minute. It also had real-time communications mode, supporting a single half-duplex voice circuit. The mission was operated by two monitoring stations in New Jersey and Puerto Rico using special 8.5 meter (28 ft.) dish antennas. Mission Profile Courier 1B launched on 4 October 1960 at 17:45 UT (1:45 p.m. EDT) from the Atlantic Missile Range in Cape Canaveral, Florida. The launch vehicle was a Thor-Able-Star, comprising a modified USAF Thor IRBM first stage and a USAF Able-Star upper stage with a re-startable liquid engine. The satellite was successfully inserted into a 106.8 minute, 28.33 degree inclination orbit with a perigee altitude of 938 km and an apogee of 1237 km. Messages were successfully received and transmitted and the satellite operated nominally until a command system failure ended communications 17 days after launch.