Space shuttle era nears its end

摘要

The landing of the space shuttle Discovery at Cape Canaveral on July 17 marked the successful completion of the 113th mission since 1981 for NASA's fleet of reusable orbiters. It was Discovery's 32nd flight since its maiden voyage in 1984. Discovery is the oldest of the three remaining shuttles, which include Atlantis and Endeavour. It is the third oldest of the original operational shuttles, which also included Challenger and Columbia. Challenger (STS-51L) was lost with its crew of seven astronauts in a launch accident in 1986. Columbia (STS-107), also with a crew of seven, was lost during reentry into Earth's atmosphere following the loss of thermal protection panels on the leading edge of the vehicle's left wing.