Washington, Feb 28: Three astrouts have landed safely in Kazakhstan on Wednesday after five-and-a-half-month of performing research and spacewalks in low-Earth orbit. The Soyuz spacecraft with SA astrouts Mark Vande Hei and Joe Acaba, and cosmout Alexander Misurkin of the Russian space agency Roscosmos landed at 8.31 a.m. in Kazakhstan, SA said. The three were part of the Expedition 54 crew aboard the Intertiol Space Station (ISS).