Today's new puzzle features the space shuttle taking off for one of it's last missions in outer space. The Space Shuttle was a crewed, partially reusable low Earth orbital spacecraft operated by the U.S. National Aeronautics and Space Administration (NASA). The first of four orbital test flights occurred in 1981, leading to operational flights beginning in 1982. It was used on a total of 135 missions from 1981 to 2011, launched from the Kennedy Space Center (KSC) in Florida. he first orbiter, Enterprise, was built purely for Approach and Landing Tests and had no capability to fly into orbit. Four fully operational orbiters were initially built: Columbia, Challenger, Discovery, and Atlantis. Of these, Challenger and Columbia were lost in mission accidents in 1986 and 2003 respectively, in which a total of fourteen astronauts were killed. A fifth operational orbiter, Endeavour, was built in 1991 to replace Challenger. The Space Shuttle was retired from service upon the conclusion of Atlantis' final flight on July 21, 2011.