The next launch attempt may be scheduled for Friday, but delays have become typical for the mission due to ongoing problems with the spacecraft’s design.
NASA has postponed the launch of the Starliner, Boeing’s first crewed spacecraft to reach the ISS. Astronauts Butch Wilmore and Suni Williams were already inside when the decision was made to cancel the flight due to alleged problems with a pressure control valve.
The valve in question is located on the fuel tank in the second stage of the Atlas V rocket. According to the CEO of the rocket manufacturer United Launch Alliance, sometimes the valves can be in a position where they start to «buzz», opening and closing rapidly — engineers have to clarify how dangerous this problem is and whether the valve needs to be replaced, so the rocket will be rolled back from the launch pad.
«Calling off today’s launch attempt», — NASA Chief Executive Bill Nelson wrote on Twitter. «As I said earlier, NASA’s first priority is safety. We will launch when we are ready».
Boeing’s goal is to become the second private company to provide crew transportation to and from the ISS, along with SpaceX. Elon Musk’s company first reached the station in 2020 with its Dragon capsule, effectively ending nearly a decade of US dependence on Russian space rockets.
Initially, the first test flight of the Starliner without a crew was planned for 2015, but was eventually postponed for 4 years. Eventually, when the launch took place, software malfunctions caused the engines to restart — the ship used too much fuel, so it never reached the ISS. The second attempt, originally scheduled for August 2021 but launched only in May 2022, was generally successful — although there were some questions about the performance of certain engines and the Starliner’s cooling system.
Eventually, when the Atlas V with the manned Starliner reaches orbit, the spacecraft will start its own engines and should reach the space station in 24 hours. The astronauts will spend about a week there, while the ship will remain docked to the ISS. After that, they will return home aboard a Starliner, which is expected to parachute into one of several designated locations in the southwestern United States.