NASA gears for a truly historic moment as it prepares the space shuttle Discovery for its 39th and final mission.

Known for its unmatched and extraordinary achievements, the space shuttle is often referred to as the workhouse of the space agency.

Built in 1984, Discover was the third operational orbiter used for both research and for International Space Station (ISS) missions. In all 38 trips, the shuttle has spent a total of 352 days in orbit and circled the earth 5,628 times.

Start the slideshow to know more and get the historic glimpses of the shuttle before it takes off for its last mission.