On May 23, 2011 at 21:35 UTC (on May 24 at 01:35 Moscow time) the Soyuz TMA-20 spacecraft undocked from the ISS.
The Soyuz Commander, Russian cosmonaut Dmitriy Kondratjev, Italian astronaut Paolo Nespoli and American astronaut Catherine Coleman were aboard the Soyuz TMA-20 to return to Earth.
Russian cosmonaut Kondratjev, the Soyuz commander, was at the controls of the spacecraft. He backed the Soyuz TMA-20 away from the station and halted it about 600 feet away. From there, Nespoli took still photographs and video of the complex with space shuttle Endeavour attached. The station slowly rotated 130 degrees to provide Nespoli with the best lighting and views during his photo opportunity.
The departure of Kondratjev, Coleman and Nespoli marked the end of Expedition 27. Remaining aboard the station are Expedition 28 Russian Cosmonaut and Commander Andrey Borisenko, NASA Flight Engineer Ronald Garan and Russian cosmonaut Aleksandr Samokutyaev.