Unmanned space missions are those using remote-controlled spacecraft. The first such mission was the Sputnik I mission, launched October 4, 1957. Unmanned missions are often more effective in carrying out scientific and observational missions than manned space missions, due to lower cost and lower risk factors.
Most American unmanned missions have been coordinated by the Jet Propulsion Laboratory, and European missions by ESOC, part of ESA (the European Space Agency). ESA has conducted relatively few space exploration missions (one example is the Giotto mission, which encountered comet Halley). ESA has, however, launched various spacecraft to carry out astronomy, and is a collaborator with NASA on the Hubble space telescope.
Unmanned programs through the ages (first mission year given, if known):
