March 18

1781 - Charles Messier rediscovers global cluster M92.
1899 - Phoebe, a moon of Saturn, becomes the first to be discovered with photographs, taken in August 1898, by William Henry Pickering.
1965 - Cosmonaut Aleksei Leonov, leaving his spacecraft Voskhod 2 for 12 minutes, becomes the first human to walk in space.