Timeline: Early Space Exploration

Soviet cosmonaut Yuri Gagarin becomes the first man in space when he goes around the Earth once inside the Vostok 1 capsule. Although Gagarin had no control during his 108-minute flight, the Soviet Union beats the United States in the international race to put man in space.

In a quick response to Gagarin's successful flight, the United States puts its first astronaut, Alan Shepard, into space aboard the Mercury-Atlas rocket Freedom 7. The sub-orbital flight lasts a little more than 15 minutes.

Gherman Titov becomes the second Soviet cosmonaut to orbit the Earth. He is in space for a little more than one day and suffered from motion sickness for most of the time.

John Glenn, aboard Friendship 7, becomes the first American to orbit Earth, completing three revolutions.

Soviet cosmonaut Valentina Tereshkova becomes the first woman in space during the three-day Vostok 6 flight. The next female to leave Earth would be two decades later.

The Soviet Union puts the first three-man crew into space. Voskhod 1 sends Vladimir Komarov, Konstantin Feoktistov and Boris Yegorov into orbit for one day to conduct medical tests.

Soviet cosmonaut Alexei Leonov conducts the first space walk during Voskhod 2. With crewmate Pavel Belyayev waiting inside the capsule, Leonov floats at the end of a 16-foot tether for 12 minutes, 9 seconds.

Gemini IV launches, beginning a four-day orbit of Earth. During the flight, Edward White performs the first U.S. astronaut space walk, floating tethered for 20 minutes and recording the historic occasion with a 16mm movie camera.

The Gemini VI space capsule with Walter Schirra and Tom Stafford aboard makes the first manned rendezvous with another spacecraft, Gemini VII with Frank Borman and James Lovell. The two vehicles did not dock, but floated several times to within several feet of each other.

Gemini VIII, commanded by Neil Armstrong and with astronaut David Scott, docks with an Agena satellite, the first docking of two spacecraft. About 30 minutes later, the Gemini began violently spinning. Armstrong restored it, and an immediate landing was executed in the Pacific Ocean.

U.S. astronauts Gus Grissom, Edward White and Roger Chafee, who were to be the Apollo I crew, die when a fire breaks out during a test of their command module. The trio are strapped into their suits in the capsule when the fire engulfs the inside. The Apollo program is delayed 14 months.

Soviet cosmonaut Vladimir Komarov is the first person to die on a space flight when his Soyuz 1 capsule comes crashing to Earth because his parachute lines tangle and are unable to slow his descent module from impacting into the Urals Mountains at high speed.

U.S. astronaut William Anders joins Gemini veterans Frank Borman and James Lovell on the Apollo 8 mission, which is the first to escape Earth orbit and two days later become the first humans to orbit another heavenly body - the moon. They stayed for 10 two-hour orbits.

First docking between two manned Soviet capsules takes place when two crewmembers - Aleksei Yelesiyev and Yevgeni Khrunov - of the Soviet Union's Soyuz 5 use handrails to pull themselves to Soyuz 4 to join fellow cosmonaut Vladimir Shatalov.

U.S. astronaut Neil Armstrong descends the nine rungs of lunar lander Eagle and becomes the first human to step on the moon during the Apollo 11 mission. He is followed by crewmate Buzz Aldrin - Michael Collins manned the lunar orbital vehicle Columbia.

U.S. astronauts Gene Cernan and Harrison Schmitt leave the lunar surface during the Apollo 17 mission. They are the last humans to have walked on the moon.