how many missions has the us sent to mars
Space exploration
The Soviet space program achieved many of the first milestones, including the first living being in orbit in 1957, the first human spaceflight ( Yuri Gagarin aboard Vostok 1 ) in 1961, the first spacewalk (by Aleksei Leonov ) on 18 March 1965, the first automatic landing on another celestial body in 1966, and the launch of the first space station ( Salyut 1 ) in 1971.