The Boeing Starliner continues to experience setbacks and new launch date has now been set down for the end of May.
A small helium leak in the Starliner’s service module caused the latest postponement.
The decision by the launch partners Boeing, NASA and United Launch Alliance means the spacecraft will be sent up no earlier than Saturday 25 May at 3:09pm USEDT (Sunday 26, 5:09am AEST).
The original May 8 launch was scrubbed due to a faulty oxygen relief valve.
A joint statement clarified the next launch window would allow crews to “work through spacecraft closeout processes and flight rationale before proceeding”.
While the helium leak would “not pose a risk at that level during the flight”, teams will continue to assess the issue before May 25.
Boeing’s Starliner will be mounted to the top of a modified Atlas V rocket for launch.
Two separations will take place after liftoff. Within the first 5 minutes, the Atlas V rocket boosters will separate from the Centaur second stage.
Centaur’s engines will then fire to further propel Starliner towards the International Space Station, before separating from the spacecraft over the North Atlantic Ocean. This process will happen within the first 14 minutes of the mission.
Two NASA astronauts – Butch Wilmore and Suni Williams – remain in quarantine in Houston, Texas. They will return to the Kennedy Space Center in Florida for the launch.
Wilmore and Williams will remain at the ISS for a week before boarding Starliner and returning to Earth.
Boeing’s Starliner spacecraft can carry 7 astronauts at a time and can be recommissioned for repeat flights every 6 months.