International Space Station spacewalks are major events in the building and maintaining of the orbital laboratory. Spacewalks are performed to install new components to the International Space Station, to re-wire systems, modules, and equipment, and to monitor, install, and retrieve scientific experiments. From 1998 to 2005, thirty-seven space shuttle missions were scheduled to assemble, outfit and begin experiments and research aboard the station. The initial spacewalk to begin the assembly of the International Space Station was held on December 7, 1998, following the launch of the first section of the station, Zarya, from Baikonur Cosmodrome, Kazakhstan, on November 20, 1998. The spacewalk attached the U.S.-built Unity node to Zarya. STS-102 crew members Susan J. Helms and James S. Voss performed the longest spacewalk on March 11, 2001. (Full list...)