1903 - Konstantin Tsiolkovsky begins a series of papers discussing the use of rocketry to reach outer space, space suits, and colonization of the solar system. Two key points discussed in his works are liquid fuels and staging.
1952 - Wernher von Braun discusses the technical details of a manned exploration of Mars in The Mars Project.
1953 - Colliers Magazine publishes a series of articles on man's future in space, igniting the interest of people around the world. The series includes numerous articles by Ley and von Braun, illustrated by Chesley Bonestell.
1957 - The USSR launches Sputnik I, the first artificial satellite.
1958 - The US launches Explorer I, the first American artificial satellite, on a Jupiter-C rocket.
1958 - US launches their first ICBM, the Atlas-B (the Atlas-A was a test article only).
1961 - the USSR launches Vostok 1, Yuri Gagarin reached a height of 327 km above Earth and was the first man to orbit earth.
- US, a Mercury capsule named Freedom 7 with Alan B. Shepard, spacecraft was launched by a Redstone rocket on a ballistic trajectory suborbital flight.
1962 - The US launches Mercury MA-6 (Friendship 7) on an Atlas D booster, John Glenn finally puts America in orbit.
1963 - The USSR launches Vostok 6, Valentina Tereshkova was the first woman (and first civilian) to orbit earth. She remained in space for nearly three days and orbited the earth 48 times.