 This documentary details the science behind all the unmanned space exploration missions from the early days of the Russian "Sputnick", through the "Veneras", "Mariners", "Voyagers" and "Vikings" right up to the modern day "Cassini" probe and the very recent Mars explorers. The documentary also takes a look at the technology currently in development that will be the unmanned space missions of the future especially the probe to explore Pluto.