The two American astronauts stranded aboard the International Space Station for nine months may have been stuck there because of the presidential election, one of their fellow spacemen thinks.

NASA was due to launch a SpaceX rocket from Florida carrying a replacement crew for the International Space Station in a mission that would set up the return to Earth of US astronauts Butch Wilmore and Suni Williams - stuck in space for nine months after a trip on Boeing's faulty Starliner.

NASA and SpaceX on Wednesday delayed the launch of a replacement crew of four astronauts to the International Space Station that would have set in motion the long-awaited homecoming of U.S. astronauts Butch Wilmore and Suni Williams.