Timeline: U.S. Space Program History

Milestones and other notable events in the U.S. history of human space exploration:

— 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 national space objective to put a man on the moon.

— Feb. 20, 1962: John Glenn becomes first American to orbit Earth.

— Jan. 27, 1967: Three U.S. astronauts die when a fire sweeps the Apollo I command module during a ground test at Kennedy Space Center.

— Dec. 21, 1968: First manned spacecraft to orbit moon, Apollo 8, comes within 70 miles of lunar surface.

— July 20, 1969: Neil Armstrong and Edwin Aldrin of Apollo XI spend 21 hours on the moon, 2 of those outside the capsule.

— 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 Schmidt.

— May 14, 1973: Skylab I, first U.S. orbiting laboratory, launched.

— July 17-19, 1975: U.S. astronauts and Soviet cosmonauts participate in Apollo-Soyuz Test Project, docking together in space for two days.

— April 12, 1981: Shuttle Columbia becomes first winged spaceship to orbit Earth and return to airport landing.

— June 18, 1983: Sally Ride becomes first American woman in space.

— Feb. 7, 1984: Astronaut Bruce McCandless performs man's first untethered spacewalk with a Manned Maneuvering Unit off the Challenger space shuttle.

— Jan. 28, 1986: Challenger shuttle explodes 73 seconds after launch, killing its crew of seven.

— March 14, 1995: Norman Thagard becomes first American to be launched on a Russian rocket. Two days later, he becomes first American to visit the Russian space station Mir.

— June 29, 1995: Atlantis docks with Mir in first shuttle-station hookup.

— Sept. 26, 1996: Shannon Lucid returns to Earth after 188-day Mir mission, a U.S. space endurance record and a world record for women.

— Oct. 29, 1998: Glenn, now 77, returns to space aboard shuttle Discovery, becoming the oldest person ever to fly in space.

— May 29, 1999: Discovery becomes first shuttle to dock with the international space station, a multinational, permanent, orbiting research laboratory.

— Nov. 2, 2000: An American and Russian crew begins living aboard the international space station.

— Feb. 1, 2003: Shuttle Columbia breaks apart over Texas, 16 minutes before it was supposed to land in Florida.