Astronauts swear during the missions

The boy scout from space

Thanks to a laser beam that reached the surface of the moon in 1969, ships at sea and cars on rural roads can now safely reach their destinations. Because it was only the moon landing that made the GPS system possible, which now works in every navigation system. As the?

The street in front of us is dark, we passed the last traffic sign ten minutes ago, the light from our car headlights only extends 50 meters into the night. It used to be the moment when panic trickled down our necks. The moment when we looked one last time at the map with the far too large scale. Desperate and cursing and admitting that we are lost. Today? Let's just follow the voice from our navigation system. "Turn left in 500 meters." All right.

The fact that the GPS gets us safely to our destination - among other things, we owe this to a technology that was first tested on the moon. Because the crew of the Apollo 11 mission left a laser reflector on the moon in addition to footprints in 1969. This reflector is still used today to precisely determine the distance between the earth and the moon. It consists of an arrangement of 100 prisms made of quartz glass, which was produced by Heraeus. NASA selected this particular glass for its extreme purity and durability. When measuring the distance, a laser beam is directed at the reflector and then the time of flight of the light back to earth is measured.

The exact position of the satellites - determined by a laser beam

The return of this laser beam was a sensation in 1969 - and a starting shot. A standard satellite technology tool developed from the laser experiment. For the use of many satellites it is very important to know their exact position in the sky. And a laser reflector makes exactly that possible, because it can be targeted by a laser beam from stations on earth. Many satellites, including those that have nothing to do with the navigation in our cars, have a laser reflector today. They are made from the same, robust Heraeus quartz glass that was built into the reflector on the moon. Numerous satellite missions such as those of NASA's earth observation satellite JASON are only possible thanks to these reflectors.

The Global Positioning System (GPS for short) as we know it today was developed by the US Department of Defense in the 1970s, shortly after the moon landing, and helps determine the exact position of a person or vehicle - no matter where you are . GPS works according to an ingeniously simple principle. More than 30 satellites orbit the earth and send radio signals to earth that are received, for example, by the navigation system in our car or the cell phone in our pocket. At least four satellites are required so that the devices can calculate our location.

The GPS satellites are regularly targeted by laser beams from earth stations on earth. The light pulse hits the reflector, which is no larger than a postage stamp and which is located on the outer skin of the satellite. The light races back from the satellite to earth and the exact position of the satellite can be calculated from the time required. And it works so well that in the future more and more satellites will be equipped with laser reflectors for ever more precise navigation here on earth. It doesn't matter whether we are out on the sea with a ship, on foot in the forest or with a car in the dark.