Space Shuttle "Challenger" (OV-099) was a Space Shuttle orbiter manufactured by Rockwell International and operated by NASA. Named after the commanding ship of a nineteenth-century scientific expedition that traveled the world, "Challenger" was the second Space Shuttle orbiter to fly into space after "Columbia", and launched on its maiden flight in April 1983. It was destroyed in January 1986 soon after launch in an accident that killed all seven crewmembers aboard. Initially manufactured as a test article not intended for spaceflight, it was utilized for ground testing of the Space Shuttle orbiter's structural design. However, after NASA found that their original plan to upgrade "Enterprise" for spaceflight would be more expensive than upgrading "Challenger", the orbiter was pressed into operational service in the Space Shuttle program. Lessons learned from the first orbital flights of "Columbia" led to "Challenger"s design possessing fewer thermal protection system tiles and a lighter fuselage and wings. This led to it being lighter than "Columbia", though still heavier than "Discovery".