Vostok 1

Vostok 1 was the first human spaceflight. The Vostok 3KA spacecraft was launched on April 12, 1961, taking into space Yuri Gagarin, a cosmonaut from the Soviet Union. The Vostok 1 mission was the first time anyone had journeyed into outer space and the first time anyone had entered into orbit. The Vostok 1 was launched by the Soviet space program and designed by the Soviet rocket scientists Sergey Korolyov and Kerim Kerimov.

Gagarin orbited the Earth once in 108 minutes. He returned unharmed, ejecting from the Vostok capsule 7 km (23,000 ft) above the ground and parachuting separately to the ground since the capsule's parachute landing was deemed too rough for cosmonauts to risk.

Ground controllers did not know if a stable orbit had been achieved until 25 minutes after launch.

The spacecraft attitude control was run by an automated system. Medical staff and spacecraft engineers were unsure how a human being might react to weightlessness, and therefore the pilot's flight controls were locked out to prevent Gagarin from taking manual control. (Codes to unlock the controls were placed in an onboard envelope, for Gagarin's use in case of emergency.) Vostok could not change its orbit, only spacecraft attitude (orientation), and for much of the flight the spacecraft's attitude was allowed to drift. The automatic system brought Vostok 1 into alignment for retrofire about 1 hour into the flight.

Retrofire took place off the west coast of Africa, near Angola, about 8,000 km (5,000 mi) from the desired landing place. The liquid-fueled retrorockets fired for about 42 seconds. Due to weight constraints there was no backup retrorocket engine. The spacecraft carried 10 days of provisions to allow for survival and natural decay of the orbit in the event the retrorockets failed.