This is a big day for NASA and space buffs around the world, who are clebrating two major anniversaries.
Today marks the 50th anniversary of the first human space flight, as well as the 30th anniversary of NASA's first space shuttle launch.
The latter anniversary is a somewhat bittersweet milestone for the U.S. space agency, which will soon retire its Space Shuttle fleet and transition into a new era.
On April 12, 1961, Russian cosmonaut Yuri Gagarin, the son of a Moscow carpenter, made history with a 108-minute orbital flight around the Earth to become the first human in space.
Gagarin's spacecraft, dubbed Vostok 1, circled Earth at a speed of about 17,000 miles per hour and reached a height of about 203 miles above Earth.
Russia's launch of the first human into space marked the beginning of the space race. A month after Gagarin's flight, NASA astronaut Alan Shepard became the first American in space.
"Yuri's first flight really did spur NASA into action, getting our astronauts into space and to the moon," said Daniel Lockney, a program specialist with NASA. "It was an exciting time."
The U.S. hit a major milestone when NASA launched Columbia, the first space shuttle craft, on April 12, 1981. The fleet of reusable space vehicles, which includes Challenger, Discovery, Atlantis and Endeavour, are designed to go into space and then return to Earth like a giant glider. The program ushered in a whole new era in space travel.
NASA noted that Columbia's original liftoff marked the first time in history a new spacecraft was launched with a crew aboard on its maiden voyage .
The NASA space shuttle craft, each of which is longer than three school buses, have collectively flown a total of 513.7 million miles, according to NASA.
Thanks largely to the efforts of the various space shuttles, NASA and its international teammates were able to build out the International Space Station.
The space shuttle Discovery deployed the Hubble Space Telescope in 1990 and the shuttle team since lifted off for five different servicing missions to maintain and upgrade the telescope's scientific instruments and operational systems.
Along with the many accomplishments, NASA has had its share of tragedy and heartbreak with the space shuttles as well.
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