Meteosat Second Generation (MSG) is equipped with a supplementary search and rescue (S&R) transponder. This instrument receives any signal that is emitted on the international S&R frequency 406 MHz. Ships, aircraft and even mountaineers carry small devices that can emit an alert signal in case of emergency. The signal received by MSG is retransmitted to ground stations, where other satellites and ground stations are tuned in to localise the source. This makes rescue operations possible at sea and in sparsely populated areas.
The Cospas Sarsat system, run by 34 countries, is handling search and rescue operations worldwide. The search and rescue transponder on MSG is a small, 1.5 kg unit, using the satellites' communication payload for signal reception and transmission.