Live coverage: Russian-American-British crew launches toward space station

Construction crews at NASA’s Kennedy Space Center are making steady progress outfitting the Space Launch System’s mobile platform with umbilical connections and access arms, and the walkway for astronauts to board the rocket is the most recent arrival at the Florida spaceport.

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.

Critical tests are on tap this weekend to confirm Boeing’s Starliner capsule can safety carry its two-person crew back to Earth despite unexpected helium leaks and degraded maneuvering thrusters, officials said Thursday.