WASHINGTON, July 8 (Xinhua) -- Space shuttle Atlantis is expected to take off Friday on the 135th and final flight in the U.S. National Aeronautics and Space Administration's (NASA) shuttle program. Its return to Earth later this month will mark the end of the 30-year program.
Below are some milestones of the U.S. shuttle era:
-- April 12, 1981: The United States blasted off into the space shuttle era after Columbia became the first shuttle to fly into orbit with two astronauts onboard.
-- April 1983: Challenger's first flight with first shuttle spacewalk
-- February 1984: First untethered space walks by Bruce McCandless II and Robert L. Stewart
-- August 1984: Discovery's first flight
-- October 1985: Atlantis' first flight
-- Jan. 28, 1986: Challenger blasted off from Kennedy Space Center. One minute and 13 seconds later, the spaceship was engulfed in a fireball which destroyed Challenger and claimed the lives of all seven astronauts onboard.
-- Sept. 29, 1988: The shuttle program launched its first return-to-flight mission with Discovery.
-- April 1990: Discovery deployed the Hubble Space Telescope, which has revolutionized the world's knowledge of astronomy.
-- May 1992: First flight of Endeavour, Challenger's replacement
-- December 1993: Endeavour and its seven crew members embarked on a mid-orbit repair mission to clear up a problem with Hubble's main mirror, and in early 1994, the first sharp images from Hubble were released.
-- June 1995: The first U.S. space shuttle-Russian Mir Space Station docking and joint on-orbit operation laid the cooperative and scientific groundwork for the much larger International Space Station that came later.
-- Feb. 1, 2003: Columbia was destroyed during re-entry, killing seven crew members.
-- July 26, 2005: Shuttle flights resume with Discovery.
-- March 7, 2011: Discovery's final flight
-- May 13, 2011: Endeavour's final flight
