from radiation while working and living in space. Radiation exposure in high doses over long periods of time can damage human cells and cause cancer or injury to the central nervous system. Launch and docking The three-member Expedition 2 crew successfully launched on 8 March 2001 on Space Shuttle Discovery during mission STS-102. They docked with the International Space Station on 10 March, but the Expedition 2 increment didn't begin until the previous crew undocked from the station on 18 March. STS-100 The first visitors to the station during Expedition 2 was the crew of STS-100, when they docked Space Shuttle Endeavour with the ISS on 21 April 2001. They spent eight days docked to the station. The primary objective of this mission was to deliver and install the Canadarm2 on the ISS, which is a robotic arm similar to the Canadarm which is used on some Space Shuttle flights. A later mission in 2002, STS-111, would deliver a movable base platform which would allow the Canadarm2 to have a larger range. ISS EP-1 On the day after the Space Shuttle undocked, the Russian spacecraft Soyuz TM-32 docked to the station, carrying two cosmonauts with previous spaceflight experience, as well as Dennis Tito, the first ever space tourist. This 8 day mission is sometimes referred to as ISS EP-1, ISS-2S, Soyuz 2 Taxi Flight, or simply by its launching spacecraft Soyuz TM-32. The Commander of this visiting mission was Kazakh cosmonaut Talgat Musabayev, who had previously been on two long-duration missions aboard the space station Mir in the 1990s. The other crew member of ISS EP-1 was Yuri Baturin, who had one other spaceflight, Mir EP-4, which was a visiting mission to Mir launched with the spacecraft Soyuz TM-28. Baturin's first mission occurred during the long-duration mission Mir EO-25, so he and Musabayev had already been in space together prior to ISS EP-1; in fact both were landed with the spacecraft Soyuz TM-27 in August 1998. STS-104 In July, Space Shuttle Atlantis docked with the station for an eight-day visit as a part of STS-104. The main objective of this mission was to install the Quest Joint Airlock onto the station. The STS-104 crew performed 3 spacewalks. First spacewalk; Joint Airlock Installation The first spacewalk occurred on 15 July, and focused on installation of the Quest Joint Airlock. The spacewalkers helped as Susan Helms, using the station's robotic arm, lifted