The National Aeronautics and Space Administration said astronauts Doug Wheelock and Shannon Walker joined Russian cosmonaut Fyodor Yurchikhin aboard a Soyuz TMA-19 craft at the Bakonur Cosmodrome in Kazakhstan for a launch Wednesday.
The mission at the ISS will include three spacewalks, NASA said. The two NASA astronauts and the Russian are to move the Soyuz to the new Mini-Research Module-1 on June 28.
Astronauts already on the space station are to return to Earth in September.
During the current deployment, the crew on board the space agency will continue scientific research investigations and station maintenance activities, NASA said.