The Vostok program represented the Soviet ambition to put the first man in space. Vostok ran between 1958 and 1963, for five years after the launch of the first satellite, Sputnik. The first craft of the Vostok program, Vostok 1, launched Yuri Gagarin into space on 12 April 1961, a step forward for humanity acknowledged internationally during "Yuri's night" celebrations on April 12th. There were six Vostok flights in all, each of which achieved a number of space "firsts" to the USSR, including:
- first human spaceflight (Vostok 1, 12 April 1961)
- first full day in space (Vostok 2, 6 August, 1961)
- first dual flight (Vostok 3 and 4, 11 August, 1962)
- longest solo spaceflight of 20th century (Vostok 5, 14 June 1963)
- first female astronaut in space (Vostok 6, 16 June 1963)
The Vostok spacecraft, the first-ever spacecraft for humans, was developed based on technology created for the Zenit spy satellite. The dual-use function of the technology was necessary to originally get Communist Party support for the program. Early launches during the Sputnik program, throughout 1960 and 1961, sent live animals or test dummies into space to get the technology ready for a human passenger. By April 1961 they were ready and Gagarin was launched. After his arrival back on Earth, he quickly became a global celebrity for his accomplishment.
The Vostok spacecraft included a spherical descent module 2.3m in diameter along with a conical instrument module of about the same size. The instrument module was left in orbit during descent. There were several problems with the two modules failing to detach properly, which caused scares for the first cosmonauts. About a third of the descent module was composed of a heat shield.
Some conspiracy theorists even believe that there may have been secret cosmonauts which died in space flights prior to Vostok 1. Given the secrecy of the Soviet government and its obsession with looking powerful in the eyes of the world, this may actually be possible.