NASA found more problems with Boeing’s Starliner, but the crew launch was scheduled for June 1

Senior managers from NASA and Boeing told reporters Friday that they plan to launch the Starliner spacecraft’s first crewed test flight on June 1, after several weeks of detailed analysis of a helium leak and a “design flaw” in the ship’s propulsion. System.

Extensive data reviews over the past two and a half weeks have settled on the likely cause of the leak, which officials described as small and stable. During these reviews, engineers also built confidence that even if the leak worsened, it would not add any unacceptable risk to the Starliner test flight to the International Space Station, officials said.

But engineers also found that an unexpected combination of technical failures in the Starliner’s propulsion system — which accounts for 0.77 percent of all possible failure modes, according to a Boeing program manager — could prevent the spacecraft from performing an deorbit burn at the end of the mission.

“While we were studying the helium leak, we also looked at the rest of the propulsion system, just to make sure there weren’t any other things we needed to worry about,” said Steve Stich, NASA’s Commercial Crew Program manager. Which awarded a $4.2 billion contract to Boeing in 2014 to develop the Starliner spacecraft.

“We found a design vulnerability…in the strut [propulsion] “We analyzed this helium leak, where for some of the very distant failures, we did not have the ability to perform an orbital burn with redundancy,” Stitch said in a press conference on Friday.

These two problems were revealed one by one, keeping the Starliner’s test flight grounded to allow engineers time to find workarounds. This is the first time astronauts will fly into orbit on a Starliner spacecraft, following two unmanned test missions in 2019 and 2022.

The Starliner program is years behind schedule, mainly due to problems with the spacecraft’s software, parachutes and propulsion system provided by Aerojet Rocketdyne. Software issues cut short Starliner’s first test flight in 2019 before it could dock at the International Space Station, and forced Boeing to fly an unplanned second test flight to gain confidence that the spacecraft is safe enough for astronauts. NASA and Boeing postponed the second unmanned test flight for about a year to overcome the problem of corroded valves in the ship’s propulsion system.

Last year, just a few months before it was scheduled to launch on a crew test flight, officials discovered a design problem with the Starliner’s canopies and found that Boeing had installed flammable tape inside the capsule’s cockpit. Boeing’s Starliner finally appeared ready to fly for a long-awaited crew test flight from Cape Canaveral Space Force Station in Florida.

NASA Commander Butch Wilmore and pilot Sonny Williams were strapped into their seats inside Starliner on May 6 when officials halted the countdown due to a malfunction in the spacecraft’s United Launch Alliance Atlas V rocket valve. ULA returned the rocket to its hangar to replace the valve, with an eye toward another launch attempt in mid-May.

But ground teams discovered a helium leak in the Starliner’s service module following the countdown. After some initial troubleshooting, the leak rate increased to about 70 psi per minute. Since then, the dropout rate has stabilized.

“This gave us pause as the leakage rate increased, and we wanted to understand what was causing this leakage,” Stitch said.