Their return vessel, the Soyuz TMA-10 spacecraft, landed safely in Dzhezkazgan, Kazakhstan, early this morning. The members of Expedition 38 leave the station to Expedition 39 crew -- commanded by Koichi Wakata of the Japan Aerospace Exploration Agency, and assisted by Russian flight engineers Rick Mastracchio and Mikhail Tyurin. Expedition 39 arrived at the station last November; they'll be joined by Expedition 40 in a few weeks.
During their 5.5 months in space, the now-Earthbound crew members orbited the planet 2,656 times, traversing 70.5 million miles.
While aboard, crew members made a variety of repairs to the space station, as well as conducted a range of experiments, including testing the growth of plant seedlings and the behavior of liquid under microgravity.
"It symbolizes what we as a human species -- not as different countries, but what we as people -- can do when we come together," NASA's Michael Hopkins said of the space station and his time in orbit.
Notable deaths of 2014 [PHOTOS]