In 1929, the German physicist Hermann Oberth developed plans for a space station from which a 100 metre-wide concave mirror could be used to reflect sunlight onto a concentrated point on the earth.
Later during World War II, a group of German scientists at a research centre in Hillersleben began to expand on Oberth's idea of creating a superweapon that could utilize the sun's energy. This so-called "sun gun" would be part of a space station 5,100 miles above Earth. The scientists calculated that a huge reflector, made of metallic sodium and with an area of 3.5 square miles, could produce enough focused heat to make an ocean boil or burn a city. After being questioned by Allied officers, the Germans claimed that the sun gun could be completed within 50 or 100 years.
Uses in popular culture
In the film Die Another Day, the twentieth installment in the James Bond series of films, the primary antagonist of the film, fictional British billionaire Gustav Graves, constructs an orbital sun gun code named "Icarus" for the use of cutting a path through the Korean Demilitarized Zone and allowing North Korean troops to invade South Korea. The device was disabled after its control console is destroyed.