Timeline of Solar System exploration

• All spacecraft that have left Earth orbit for the purposes of Solar System exploration (or were launched with that intention but failed), including lunar probes.
• A small number of pioneering or notable Earth-orbiting spacecraft.

It does not include:

• Centuries of terrestrial telescopic observation.
• The great majority of Earth-orbiting satellites.
• Space probes leaving Earth orbit that are not concerned with Solar System exploration (such as space telescopes targeted at distant galaxies, cosmic background radiation observatories, and so on).
• Probes that failed at launch.

The dates listed are launch dates, but the achievements noted may have occurred some time later—in some cases, a considerable time later (for example, Voyager 2, launched 20 August 1977, did not reach Neptune until 1989).

1950s