Weather satellites lend a hand in search and rescue


The Geostationary Operational Environmental Satellite (GOES) constellation's primary role is to monitor Earth's environment and provide meteorologists with data that could help them predict weather. Now these same satellites can also lend a hand in search and rescue operations in times of crisis.

GOES observations have tracked thunderstorms, tornadoes, hurricanes and flash floods. They've even proven useful in monitoring dust storms, forest fires and volcanic activity. Recently GOES-S was launched, which is going to replace the GOES-West later this year. All the GOES satellites carry payload supported by NASA's Search and Rescue (SAR) office, which researches and develops technologies to help first responders locate people in distress worldwide, whether from a plane crash, a boating accident or other emergencies.

The GOES SAR transponders are geostationary, meaning that they appear "fixed" relative to a user on the surface due to their location over the equator and orbital period of 24 hours.

The GOES search and rescue transponders, unlike SAR instruments in other orbits, are only able to detect the beacon signals, not help to determine location. This detection rapidly alerts the global SAR network, Cospas-Sarsat, of a distress beacon's activation. This gives the system valuable time to prepare before the signal's origin can be determined by SAR instruments on low-Earth-orbiting satellites.

Additionally, beacons with integrated GPS technology can send their location data through GOES to the SAR network. The network can then alert local first responders to the location of the emergency without the aid of the low-Earth-orbiting constellation of search and rescue instruments.

NASA's SAR team provides on-orbit testing, support and maintenance of the search and rescue instrument on GOES. The GOES satellites and SAR instruments are funded by NOAA.

In the future, first responders will rely on a new constellation of instruments on GPS and other Global Navigation Satellite Systems currently in medium-Earth orbit, an orbit that views larger swathes of the Earth than low-Earth orbit due to higher altitudes. These new instruments will enable the SAR network to locate a distress signal more quickly than the current system and calculate their position with accuracy an order of magnitude better, from one kilometer (0.6 miles) to approximately 100 meters (328 feet).

In the meantime, the SAR transponders aboard GOES cover the time between the activation of a distress signal and detection by SAR instruments in low-Earth orbit.