Before revision: While seldom seen, the International Code of Signals allows for the exclusive use of a flashing blue lights (60 to 100 flashes/minute) and visible from as many directions as possible, by medical aircraft to signal their URL page 146 Spacecraft navigation In 2011, ORBITEC developed the first light-emitting diode (LED) system for use as running lights on spacecraft.
After revision: While seldom seen, the International Code of Signals allows for the exclusive use of a flashing blue lights (60 to 100 flashes/minute) , visible from s many directions as possible, by medical aircraft to signal their URL page 146 Spacecraft navigation In 2011, ORBITEC developed the first light-emitting diode (LED) system for use as running lights on spacecraft.