One Russian cosmonaut and one American astronaut are about to become very familiar with each other.

In late November it was announced that Scott Kelly and Mikhail Kornienko will launch from Kazakhstan in spring 2015 and dock at the International Space Station, where they will spend a full year in orbit above the earth.

The journey will be the longest American spaceflight ever, eclipsing the 215-day record previously set by astronaut Michael Lopez-Alegria in 2006-2007.

The Russians have endured long spaceflights before, with 5 cosmonauts having spent more than 300 days in orbit. Cosmonaut Valeri Polyakov, who spent 437.7 days mostly on the Mir space station in 1994-1995, holds the record for the longest spaceflight. His trip set the stage for the upcoming American-Russian trip, providing valuable information about the safety of long-term human space flight.

After Kelly and Kornienko’s trip, we will know even more about the effects of space on bone density, muscle mass, vision and mood.

“Their skills and previous experience aboard the space station align with the mission’s requirements,” said William Gerstenmaier at NASA. “The one-year increment will expand the bounds of how we live and work in space and will increase our knowledge regarding the effects of microgravity on humans as we prepare for future missions beyond low-Earth orbit.”

In accepting the mission, Kelly has the red planet on his mind. “I personally think our ultimate destination, at least for a long time in our planet’s future, is getting to Mars,” he tells CBS News. “And I look at this as a step towards that.” A one-way trip to Mars is expected to take 150-300 days.

Kelly and Kornienko start training for the mission early next year.