NASA astronaut Mark Vande Hei could spend one year onboard space station

He was added to the next Soyuz crew, in order to keep a constant US presence on the ISS, as operations would be hampered if no Americans were on board.

from http://www.firstpost.com/tech/science/nasa-astronaut-mark-vande-hei-could-spend-one-year-onboard-space-station-9423571.html