U.S. astronaut Scott Kelly and Russian cosmonaut Mikhail Kornienko returned to Earth on March 2 after spending almost a year in space.
The astronauts parachuted onto the barren, frozen Kazakhstan steppes after a 3 1/2 hour flight home piloted by Russian cosmonaut Sergey Volkov.
Kelly and Kornienko had circled the Earth 5,440 times and travelled 143 million miles during the 340days they spent in space.
Their ground-breaking long visit to the International Space Station, the longest for any American, was designed to test human reactions to being in space for prolonged periods in preparation for a manned mission to Mars in coming years.
Kelly was also part of an experiment comparing his development and changes in space with his identical twin brother -- Mark -- back on Earth.
Kelly captured imaginations worldwide by posting stunning views of Earth from space on his Instagram page and tweeting regularly to nearly a million followers.
Russia continues hold the world record for duration in space of 438 days.
