Notable events in the history of human space exploration:
_ Oct. 4, 1957: First artificial satellite, Sputnik I, is launched by Soviet Union.
_ April 12, 1961: Soviet cosmonaut Yuri Gagarin completes the first manned space flight, orbiting the Earth in 108 minutes.
_ May 5, 1961: U.S. launches first American astronaut, Alan Shepard Jr., into space, on a 15-minute, 22-second suborbital flight.
_ May 25, 1961: President Kennedy declares the American space objective to put a man on the moon and return him safely by the end of the decade.
_Feb. 20, 1962: John Glenn becomes first American to orbit Earth, completing three orbits.
_ June 16-19, 1963: Cosmonaut Valentina Tereshkova, the first woman in space, completes 48 orbits.
_ March 18, 1965: Cosmonaut Aleksei Leonov takes man’s first space walk.
_ Jan. 27, 1967: Astronauts Gus Grissom, Edward White and Roger Chaffee die when a fire sweeps the Apollo I command module during a ground test at Kennedy Space Center.
_ April 24, 1967: Cosmonaut Vladimir Komarov is killed when his Soyuz I spacecraft crashes on return to Earth.
_ Dec. 21, 1968: First manned spacecraft to orbit moon, Apollo 8, comes within 70 miles of lunar surface.
_ July 20, 1969: Man walks on the moon. Neil Armstrong and Edwin “Buzz” Aldrin of Apollo XI spend 21 1/2 hours on the moon, 2 1/2 of those outside the capsule.
_ June 29, 1971 - Three cosmonauts, Georgy Dobrovolsky, Vladislav Volkov and Viktor Patsayev, die during re-entry of their Soyuz 11 spacecraft. A government commission disclosed that the three died 30 minutes before landing because a faulty valve depressurized the spacecraft.
_ Dec. 7-19, 1972: Apollo 17 mission that includes the longest and last stay of man on the moon _ 74 hours, 59 minutes _ by astronauts Eugene Cernan and Harrison Schmitt.
_ May 14, 1973: Skylab I, first U.S. orbiting laboratory, launched.