NASA has yet to fix a return date for its two astronauts at the International Space Station, who have now been stuck there for more than a month due to technical issues with the Boeing-manufactured Starliner capsule intended to bring them back to Earth. The new spacecraft experienced thruster failures and helium leaks upon docking at the ISS in early June. The US space agency says it is also reviewing backup return options including using SpaceX's Dragon capsule.