When will the multi-billion spacecraft fly? Boeing says first manned launch on June 1.

NASA and Boeing plan to conduct the first manned launch of Boeing's Starliner spacecraft on June 1. Engineers are investigating the cause of a helium leak and its impact on critical mission components, as announced on Wednesday.

The helium leak in the Starliner's propulsion system delayed the originally scheduled May 7 manned mission. As NASA and Boeing work to resolve the issue and perform new tests on the spacecraft, the launch date has been repeatedly postponed.

The U.S. space agency stated that engineers have expanded their inspection of the helium leak, tracing it to a valve component in a single thruster, while also assessing the Starliner's propulsion system and its potential impact.

The Starliner's helium system is used to pressurize the fuel for the thrusters, which are employed to maneuver the spacecraft in orbit.

Developed by Boeing, the Starliner spacecraft is designed to transport NASA astronauts to the International Space Station (ISS). However, the project has been delayed for years and has exceeded the budget by over $1.5 billion due to development challenges. The ongoing issues with Starliner's development highlight Boeing's difficulties in competing with Elon Musk's SpaceX under tight budget constraints.

The first manned flight of the Starliner will include NASA astronauts Suni Williams and Butch Wilmore. This mission represents the final test before NASA certifies the Starliner for regular missions.

NASA stated that if the June 1 launch window is missed, Boeing has additional opportunities to launch on June 2, 5, and 6.