The Soviet space program was mainly based on the human spaceflight program and the development of the expendable launch vehicles, which had been split between many design bureaux competing against each other. Over its 60 years of history, the Soviet space program was responsible for a number of major firsts in human spaceflight, including the first intercontinental ballistic missile (R-7), first satellite (Sputnik 1), first animal in Earth orbit (the dog Laika on Sputnik 2), first human in space and Earth orbit (Yuri Gagarin on Vostok 1), first woman in space and Earth orbit (Valentina Tereshkova on Vostok 6), first spacewalk (Alexei Leonov on Voskhod 2), first Moon impact ("Luna 2"), first image of the far side of the Moon ("Luna 3") and uncrewed lunar soft landing ("Luna 9"), first space rover ("Lunokhod 1"), first sample of lunar soil automatically extracted and brought to Earth ("Luna 16"), and first space station (Salyut 1). Further notable records included the first interplanetary probes: Venera 1 and Mars 1 to fly by Venus and Mars, respectively, Venera 3 and Mars 2 to impact the respective planet surface, and Venera 7 and Mars 3 to make soft landings on these planets.