Nasa has developed contingency plans to bring two stranded astronauts home from the International Space Station (ISS) early next year following problems with Boeing’s Starliner capsule.

The long-delayed Starliner achieved its first crewed launch in June after years of delays, successfully docking with the ISS for Barry Wilmore and Sunita Williams to undertake an eight-day mission before heading back to Earth.

But the plans went awry when, during the docking procedure with the ISS, Starliner suffered various thruster failures and helium leaks. This forced the astronauts to remain aboard the ISS for two months while Nasa figured out how to get them home.

While Nasa is still looking at ways it could continue to use Starliner to bring the astronauts back to Earth earlier, it is also considering bringing them home on a SpaceX Dragon capsule in 2025.

Steve Stich, the manager of Nasa’s commercial crew programme, said: “Our prime option is to return Butch and Sunny on Starliner; however, we have...