A Russian cosmonaut and a U.S. astronaut will fly to the International Space Station for the first-ever yearlong mission in 2015, officials said.

The Russian Federal Space Agency Roscosmos and other partners in the ISS project came to an agreement on the mission Friday, ITAR-Tass reported.

The ISS mission is to start in spring 2015, and will end a year later when the two crew members return to Earth in the Russian spaceship Soyuz, NASA reported.

The final crew and details of the mission will be determined through further negotiations between the partners.

This will be the first mission to last longer than several months, with the hopes that the crew members will be able to gather the scientific data needed for future manned flights in the solar system, NASA said.