Rockets first saw use in military applications in ancient China in the 13th century, and they saw intermittent development thereafter in China and then with greater focus in Europe. It was, however, only in the late 19th and early 20th century that the ‘Father of Russian cosmonautics,’ the Russian Constantin Tsiolkovsky, developed the theoretical basis for rockets as means to escape the Earth’s gravity and explore space. Further groundbreaking work was undertaken by the American Robert H Goddard and the German Herman Oberth.