SpaceX has launched its Crew Dragon spacecraft on a “rescue mission” to bring back two astronauts stranded at the International Space Station (ISS) since June. Butch Wilmore and Suni Williams travelled to the space station on Boeing’s Starliner spacecraft, which was on its first mission with a human crew. But several engines malfunctioned once in space and the vehicle was found to be leaking helium, which is essential for the functioning of its engines. After weeks of analysis and discussion by Nasa and Boeing engineers, the space agency decided to send Wilmore and Williams home on the Crew Dragon because…