STS-87 "Columbia" (November 19 to December 5, 1997) was the fourth U.S Microgravity Payload flight and focused on experiments to study how the weightless environment of space affects various physical processes, and observations of the Sun's outer atmospheric layers. Two members of the crew performed an EVA (spacewalk) which featured the manual capture of a Spartan satellite and also tested EVA tools and procedures for future Space Station assembly. The mission was accomplished in 252 Earth orbits during which the crew traveled 6.5 million miles in 376 hours, 34 minutes.