NASA - Examples of robotic missions

Reference 1: Launch year

Reference 2: Mariner 2, Mariner 4, Mariner 5, Mariner 6 and 7, Mariner 9, Pioneer 10, Pioneer 11, Mariner 10, Viking 1 Viking 2, Voyager 1, Voyager 2, Galileo, Magellan, Mars Global Surveyor, Cassini, Mars Odyssey, Spirit Opportunity, MESSENGER, MRO, New Horizons, Juno, Curiosity (MSL), MAVEN and Spacecraft.

Source: http://en.wikipedia.org/wiki/NASA