What went wrong with Boeing's troubled Starliner spacecraft?

Boeing's Starliner mission to the International Space station has not been their finest moment. Astronauts Suni Williams and Butch Wilmore first travelled to the station in early June aboard a Boeing Starliner spacecraft for what was expected to be a week-long test mission. But issues with helium leaks and malfunctioning thrusters forced NASA to decide Starliner’s problems were not well enough understood for the space agency to allow Williams and Wilmore to return to Earth on it. Jason Rabinovitch is an Assistant Professor in the Mechanical Engineering Department at Stevens Institute of Technology in New Jersey. Before that he worked at NASA's Jet Propulsion Laboratory for more than six years