NASA built six Space Shuttles, reusable low Earth orbital spacecraft. Enterprise was used only for flight tests. Columbia, Challenger, Discovery, Atlantis and Endeavour were used to launch satellites, conduct science experiments in orbit and service the International Space Station.
135 missions were flown between 1981 and 2011. Challenger and Columbia were both destroyed in mission accidents. Challenger exploded 73 seconds into its flight on 28 January, 1986, killing all seven crew members.
Only those who will risk going too far can possibly find out how far one can go.