with the needs, the standards and the applicable recommendations of the global community. Cospas-Sarsat is an element of the IMO's Global Maritime Distress Safety System (GMDSS), and is a component of ICAO's Global Aeronautical Distress and Safety System (GADSS). The IMO requires automatic-activating Cospas-Sarsat beacons (EPIRBs, see below) on all vessels subject to requirements of the International Convention for the Safety of Life at Sea (so-called SOLAS-class vessels), commercial fishing vessels, and all passenger ships in international waters. Similarly, ICAO requires Cospas-Sarsat beacons aboard aircraft on international flights, as well as the ability to track such aircraft when in distress (see "Beacons" under "System architecture" below). National administrations often impose requirements in addition to the international requirements of those agencies. Cospas-Sarsat only monitors for alerts from digital distress beacons that transmit on 406 MHz (so-called 406 beacons). Older beacons that transmit using the legacy analog signal on 121.5 MHz or 243 MHz rely on being received only by nearby aircraft or rescue personnel. For satellite reception of alerts by Cospas-Sarsat the beacon must be a model that transmits at 406 MHz. Cospas-Sarsat has received many honors for its humanitarian work, including induction into the Space Foundation's Space Technology Hall of Fame for space technologies improving the quality of life for all humanity. System operation The system consists of a ground segment and a space segment that include: Distress radio-beacons to be activated in a life-threatening emergency SAR signal repeaters (SARR) and SAR signal processors (SARP) aboard satellites Satellite downlink receiving and signal processing ground stations called LUTs (local user terminals) Mission control centres (MCCs) that distribute to rescue coordination centres distress alert data (particularly beacon location data) generated by the LUTs Rescue coordination centres (RCCs) that facilitate coordination of the SAR agency and personnel response to a distress situation. Beacons A Cospas-Sarsat distress beacon is a digital 406-MHz radio transmitter that can be activated in a life-threatening emergency to summon assistance from government authorities. Beacons are manufactured and sold by dozens of vendors. They are classified in three main types. The beacons designed for use in an aircraft is known as an emergency locator transmitter (ELT). One designed for use aboard a marine vessel is called an emergency position-indicating radio beacon (EPIRB). And one that is designed to be carried by an individual is known as a personal locator beacon (PLB). Sometimes PLBs are carried aboard aircraft or vessels, but