The Boeing Starliner spacecraft launched for the first time with astronauts on board. But during the flight, a helium leak was discovered again

After almost 20 years of planning, development, testing and delays, the Boeing Starliner spacecraft made its first manned launch and sent astronauts to the ISS as part of the Crew Flight Test (CFT) mission. The launch of the Atlas V rocket with the Starliner capsule took place on June 5 at 17:52 Kyiv time.

The spacecraft was carrying NASA test astronauts Barry «Butch» Wilmore and Suni Williams. Docking with the ISS is scheduled for 19:15 (Kyiv time) on June 6. The astronauts will then spend 8 days on board the station, conducting a series of tests and capsule tests required for certification. The CFT mission is focused on thoroughly checking the Starliner before certifying the spacecraft for longer missions. Williams and Wilmore will perform several manned flights, test emergency scenarios such as loss of communication or power, and conduct many analyses so that future Starliner crews know what to expect.

It should be noted that this launch was preceded by several setbacks. Initially, the CFT mission was scheduled for May 6. But This attempt was canceled about two hours before the launchwhen team members noticed a «humming» valve on the top of the Atlas V. To fix the problem, the rocket had to be rolled off the pad to the vertical integration facility. This work postponed the scheduled launch until May 17. But then another problem arose – a small helium leak in one of the engines in the Starliner service module.

The mission team analyzed the leak and its potential consequences and ultimately deemed it a minor issue, allowing CFT to proceed with its scheduled launch on June 1. However, the June 1 attempt was aborted minutes before takeoff due to a malfunction of the power distribution source in the ground equipment. The mission team replaced the faulty equipment, setting up CFT for this launch, which finally succeeded.

Although this time it was not without problems. Speaking to ground controllers on Wednesday afternoon, Wilmore said that so far, the Starliner «test flight had simply gone off without a hitch. But as the crew prepared for the night shift, the capsule developed two new helium leaks in the service module. So, three of the eight helium manifolds on the Starliner now show signs of leakage. The astronauts had to manually close the valves on the manifolds that were found to have leaks in flight. At the same time, the manifold that was known to have a leak before launch will remain open.

Despite these problems, the vehicle retains the ability to maneuver. According to Steve Stich, NASA’s commercial program manager, before agreeing to launch with a known helium leak, engineers determined that the Starliner spacecraft could handle four more helium leaks, even if the existing leak worsened. In the current configuration, with two closed helium manifolds, 6 of the spacecraft’s 28 reaction control system engines will be shut down. The capsule has the ability to operate with a subset of the engines, and Boeing engineers believe that «the helium system remains safe for flight».

If all goes well with the CFT, the Starliner will deliver its first crew of astronauts to the ISS for about six months, possibly as early as 2025.

Source: space, arstechnica