OSCAR-1 satelliteOSCAR-1, an experimental satellite designed and built by amateur radio engineers for a technology test, is launched as a secondary payload aboard an Air Force rocket whose primary payload is a reconnaissance satellite. This is the first launch in history with a secondary payload, and the first payload not developed by a specific government or its agencies. The amateur radio engineers of Project OSCAR built the simple transmitter satellite for a grand total of $35, with a finite battery life and no attitude control thrusters of any kind, to transmit the message “HI” in the 2-meter band until the battery expired (which happens a few weeks before the satellite re-enters Earth’s atmosphere in late January 1962). A nearly-identical OSCAR-2 satellite will be launched in June 1962, while OSCAR-3, launched in 1965, is capable of receiving and retransmitting signals.