when did exploration to the inner solar system begin
Discovery and exploration of the Solar System The first successful probe to fly by another Solar System body was Luna 1, which sped past the Moon in 1959. Originally meant to impact with the Moon, it instead missed its target and became the first artificial object to orbit the Sun. Mariner 2 was the first probe to fly by another planet, Venus, in 1962. The first successful flyby of Mars was made by Mariner 4 in 1965. Mariner 10 first passed Mercury in 1974.
Yuri Gagarin Yuri Alekseyevich Gagarin (Russian: Ю́рий Алексе́евич Гага́рин[note 1], IPA: [ˈjʉrʲɪj ɐlʲɪˈksʲejɪvʲɪtɕ ɡɐˈɡarʲɪn]; 9 March 1934 – 27 March 1968) was a Soviet pilot and cosmonaut. He was the first human to journey into outer space when his Vostok spacecraft completed an orbit of the Earth on 12 April 1961.