Two Russian cosmonauts and an American astronaut returned Thursday after spending nearly six months aboard the International Space Station, or ISS, even as tensions built up between the two countries on planet Earth. The astronauts landed in Kazakhstan, the Russian space agency Roscosmos and NASA said, in separate statements.

The astronauts -- Steven Swanson, Alexander Skvortsov and Oleg Artemyev -- spent 169 days in space during which time Skvortsov and Artemyev conducted two spacewalks. The three astronauts who left for the ISS on March 26, orbited the Earth 2,700 times and travelled more than 71.7 million miles during their time in space, NASA said in a statement.

"One of several key research focus areas during Expedition 40 was human health management for long duration space travel as NASA and Roscosmos prepare for two crew members to spend one year aboard the orbiting laboratory in 2015," Agence France-Presse, or AFP, reported citing a statement released by NASA.

Swanson, who has travelled to space twice before, handed over the command of the space station to Max Suraev, another Russian cosmonaut aboard the ISS, before departing back for Earth.

"We had a lot of fun," Swanson, who will fly back home aboard a U.S. jet, said, according to Associated Press, or AP.

In April, NASA announced that it was limiting cooperation on space-related projects with Russia, because of the latter's role in the conflict in Ukraine. However, the American agency added that the work at the space station will not be affected, AFP reported.

Roscosmos is scheduled to send a fresh three-person team on Sept. 25, which will include a Russian woman, Elena Serova. She will be the fourth Russian woman to travel to space and the first one in nearly 20 years, AP reported. The new team will join the three astronauts currently aboard the space station.