- 2 April 1968 – The epic science fiction film, 2001: A Space Odyssey is released
- 3 April 2014 – NASA announces that the Cassini orbiter has found evidence of an underground body of water on Enceladus, a moon of Saturn
- 7 April 2001 – Mars Odyssey orbiter is launched to map and search for water on Mars
- 12 April 1961 – Cosmonaut Yuri Gagarin becomes the first human to enter outer space when he is launched into orbital flight in Vostok 1
- 19 April 1971 – The first space station, Salyut 1, is launched into orbit
- 24 April 1990 – The Hubble Space Telescope, a powerful research tool and public relations boon for astronomy, is launched into orbit
