The surface area of Saturn's moon Mimas is slightly less than the land area of Spain and is composed of water ice with only a small amount of rock. Yet Saturn's resonances with Mimas, and Mimas' resonances with other orbiting satellites are instrumental in the formation of Saturn's rings
For more than 50 years, NASA's robotic deep space probes have carried nuclear batteries provided by the U.S. Department of Energy. Even the crewed Apollo moon landings carried nuclear powered equipment.
ILS Instrument Landing System, electronic equipment that guides an airplane precisely onto the runway. Two of its subsystems, 'localizer' and 'glide slope,' are radio transmitters on the ground which define respectively the straight-in course over the ground and the vertically slanting path to the touch-down point. A pair of needles on the panel provide the requisite guidance. On my approaches, it looks like a sword fight. Outer - Middle - Inner Marker