An Antares rocket carrying the Cygnus cargo ship has exploded moments after lift off from Wallops Island, Virginia.

Helium leaks and thruster issues prompted NASA to extend their stay aboard the space station indefinitely — Wednesday marked their 35th day in orbit — while engineers carry out tests and analysis to better understand what caused the problems and to make sure the spacecraft can safely being Wilmore and Williams home.

NASA and SpaceX have delayed the launch of the Crew Dragon “Resilience” spacecraft from the Kennedy Space Center until 7:27 p.m. EST Sunday (0027 GMT Monday) to wait for improved downrange weather and sea conditions, and better onshore winds at the launch site.