The basic Soyuz spacecraft design was the basis for many projects, many of which never came to light. Its earliest form was intended to travel to the moon without employing a huge booster like the Saturn V or the Soviet N-1 by repeatedly docking with upper stages that had been put in orbit using the same rocket as the Soyuz. This and the initial civilian designs were done under the Soviet Chief Designer Sergei Pavlovich Korolev, who did not live to see the craft take flight. Several military derivatives took precedence in the Soviet design process, though they never came to pass.
A Soyuz spacecraft consists of three parts (from front to back):
The Zond spacecraft was another derivative, designed to take a crew traveling in a figure-eight orbit around the Earth and the moon but never achieving the degree of safety or political need to be used for such.
Finally, the Progress series of unmanned cargo ships for the Salyut and Mir space laboratories used the automatic navigation and docking mechanism (but not the re-entry capsule) of Soyuz.
As of 2011, Soyuz derivatives provide much of mankind's human spaceflight capability and are used to ferry personnel and supplies to and from the International Space Station. Following the retirement of the USA's Space Shuttles, Russia has the sole proven system for boosting crew to the station.