Three new crew members arrived at the International Space Station on Thursday and three will depart on Sunday. A Soyuz spacecraft is currently docked at the end of the Zvezda service module, and a live stream, courtesy of NASA, will begin at 6 p.m. EST to follow the undocking and return of three astronauts after more than 100 days in space.

ISS Crew
The three crew members in blue, Oleg Kotov, Karen Nyberg and Luca Parmitano are leaving the ISS on Sunday. NASA TV

Expedition 37 crew members Karen Nyberg, from NASA, Luca Parmitano, from the European Space Agency, and Russian cosmonaut Fyodor Yurchikhin are set to return to Earth after 166 days in space, reports NASA. Yurchikhin served as the ISS commander and will be replaced by fellow cosmonaut Oleg Kotov. In addition to the three astronauts, the Soyuz capsule is also carrying special cargo: the Olympic torch. Kotov and cosmonaut Sergey Ryazanskiy carried the Olympic torch during Saturday's spacewalk, taking the flame out of the ISS as part of the 2014 Winter Olympics torch relay. The Olympic torch arrived on Thursday with the three Expedition 38/39 crew members. According to NASA, it was the first time in three years that nine astronauts were aboard the ISS at once.

Sunday's depature caps off a busy week for the ISS, which included the arrival of three new crew members and the spacewalk. According to NASA, the Soyuz spacecraft will undock at 6:27 p.m. EST. The capsule will perform a deorbit burn, which requires the spacecraft to turn "tail-first into the direction of travel to prepare for another firing of the orbital maneuvering system engines." This process will occur at 8:55 p.m. EST with an expected landing in Kazakhstan at 9:49 p.m. EST.

NASA's undocking live stream begins at 6 p.m. and can be viewed below.

Live streaming video by Ustream