Persistent concerns with the vehicle’s propulsion systems mean Suni Williams and Butch Wilmore will return home next year in a SpaceX vehicle. Williams, Sunita L, Wilmore, Barry E (Butch) (1962- ), Space and Astronomy, International Space Station, National Aeronautics and Space Administration, Space Exploration Technologies Corp, Boeing Company, Private Spaceflight, Rocket Science and Propulsion Persistent concerns with the vehicle’s propulsion systems mean Suni Williams and Butch Wilmore will return home next year in a SpaceX vehicle. NYT > Business