STS-102 mission astronaut Susan J. Helms works outside the International Space Station (ISS) while holding onto a rigid umbilical and her feet anchored to the Remote Manipulator System (RMS) robotic arm on the Space Shuttle Discovery during the first of two space walks. During this space walk, the longest to date in space shuttle history, Helms in tandem with James S. Voss (out of frame), prepared the Pressurized Mating Adapter 3 for repositioning from the Unity Module's Earth-facing berth to its port-side berth to make room for the Leonardo Multipurpose Logistics Module (MPLM) supplied by the Italian Space Agency. The Leonardo MPLM is the first of three such pressurized modules that will serve as the ISS's moving vans, carrying laboratory racks filled with equipment, experiments, and supplies to and from the Station aboard the Space Shuttle. The cylindrical module is approximately 21-feet long and 15- feet in diameter, weighing almost 4.5 tons. It can carry up to 10 tons of cargo in 16 standard Space Station equipment racks. Of the 16 racks the module can carry, 5 can be furnished with power, data, and fluid to support refrigerators or freezers. In order to function as an attached station module as well as a cargo transport, the logistics module also includes components that provide life support, fire detection and suppression, electrical distribution, and computer functions. Launched on May 8, 2001 for nearly 13 days in space, STS-102 mission was the 8th spacecraft assembly flight to the ISS and NASA's 103rd overall mission. The mission also served as a crew rotation flight. It delivered the Expedition Two crew to the Station and returned the Expedition One crew back to Earth.