WASHINGTON – NASA is expected to decide Saturday whether two astronauts who arrived at the International Space Station aboard Boeing’s Starliner should return on that craft — or brace for a longer wait to fly home with rival SpaceX.The latter solution would not only create a fresh public relations headache for Boeing, but possibly result in astronauts Butch Wilmore and Suni Williams spending a total of eight months in orbit, not the eight days as originally planned.A decision-making committee, with NASA chief Bill Nelson sitting in, will meet Saturday to weigh the tough issue.The US space…