Spare a thought for Suni Williams and Butch Wilmore, and not just because they’re stuck on the International Space Station for another six months on a trip that was supposed to end in July. They know now they would probably have survived re-entry in the Starliner capsule that returned to Earth without them on Friday, even though Boeing and Nasa still aren’t quite sure what made five of its 28 helium manoeuvring thrusters malfunction during docking with the ISS. On reentry and final descent to New Mexico, the empty spacecraft performed fine. But those it left behind until SpaceX rescues them in February may be frustrated for a third reason. In their absence Elon Musk has brought forward his estimate of SpaceX’s first human mission to Mars by three years. Will Williams and Wilmore get back in time for the selection process?