Investigators say Boeing Starliner malfunction likely caused by humid air in Florida


Starliner inside a vertical integration facility.

Starliner inside a vertical integration facility.
picture: Boeing

Engineers at Boeing and NASA are working to study the root cause of the technical glitch that canceled the Starliner test launch. A promising theory suggests that moisture got into the spacecraft’s propulsion system, causing critical valves to stop. As to how this moisture enters, it is now a question that needs to be answered.

“It’s time to bring the Starliner back to the factory,” John Vollmer, vice president and director of Boeing’s Commercial Crew Program, formally explained during a NASA conference call. Today. The spacecraft will be lowered from the top of a United Launch Alliance Atlas V rocket and transported to the Boeing plant at Kennedy Space Center, which previously served as the space shuttle processing facility.

The Starliner has been parked inside the ULA Vertical Integration Facility for over a week now as engineers with both Boeing and NASA have triedJobs recoveryto 13 oxidizer valves that did not open during the countdown to its August 3 launch. It was to be the second uncrewed test flight of the CST-100 Starliner And its first flight since late 2019. For the first test, Starliner had already managed to take off from Earth into space, but a program failure prevented it from reaching its intended destination, the International Space Station. Boeing made its way through Numerous fixes Over the past year and a half, resulting in an indefinitely postponed orbital flight test-2 (OFT-2).

The United Launch Alliance's Atlas V rocket with the Boeing CST-100 Starliner spacecraft at Space Launch Complex 41 in Cape Canaveral on August 2, 2021.

The United Launch Alliance’s Atlas V rocket with the Boeing CST-100 Starliner spacecraft at Space Launch Complex 41 in Cape Canaveral on August 2, 2021.
picture: NASA/Joel Kosky

“We’re not disappointed,” Kathryn Lueders, NASA associate administrator for Human Exploration and Operations, told reporters during the conference call. “We are just sad,” she said, adding that “we will learn from this.”

Lueders was the designated optimist of the press conference, persistently framing the situation in glass-half-full terms and refraining from directing critical words towards NASA’s commercial partner Boeing.

“We’re going to go fix this problem, and we’re going to move forward,” Lueders said. “And we’re going to fly when we’re ready.” It was a “disappointing day,” she said, but “this is why the demo missions are so important.”

Specialists managed to move seven of the stuck valves by August 10 and nine by August 13. All but four of the 13 valves were recovered, but after having “done everything we can on those,” Boeing “ultimately decided to stop and go back to the factory” where engineers will continue with further troubleshooting, as Vollmer explained. The plan, he said, is to disassemble as little of Starliner as possible to minimize tweaks to the current configuration.

Vollmer, along with Steve Stich, manager of NASA’s Commercial Crew Program, shared new details about the problem and what possibly went wrong.

Starliner is equipped with 24 oxidation valves, 24 fuel valves, and 16 helium valves. These valves isolate thrusters from propellant tanks, and they need to be open prior to launch. The “most likely root cause” of the problem, said Vollmer, is that moisture somehow got onto the dry side of the oxidation valves, resulting in the formation of nitric acid. Friction from the ensuing corrosion caused the 13 valves to get stuck, according to this theory. The moisture could have entered into the system during assembly of Starliner, during check-outs prior to launch, or while the spacecraft was on the launch pad, as Stich explained.

Vollmer said it’s possible that atmospheric moisture somehow crept into the system and permeated the valve covers. Water splashing in from an intense storm that swept through the launch pad a day prior to the scheduled launch is likely not the source of this moisture, he added. It’s not known if a redesign is required or if preventative measures will do the trick, but it’s “certainly something that needs to be resolved,” said Vollmer.

“We use teflon seals that can withstand NTO [nitrogen tetroxide], which is a highly corrosive oxidizer,” Vollmer said. “We know there is penetration through this seal,” he said, so specialists will have to “go back to see if ambient moisture was retained during assembly” of the Starliner, or if something else caused moisture to find its way into the valves afterward. .

He added: “There are a lot of things on the error tree, and a lot of things on the error tree that interact with each other, but this is so far the main candidate for the cause of the error.”

Vollmer said the valves had been checked five weeks before launch, and that they were “working perfectly.” What’s more, it’s the same design used during the Orbital Flight Test-1 and on pad abort test vehicles. Since rockets are being launched from Florida all the time, he said, engineers will have to figure out why the moisture suddenly appeared, if indeed that was the cause. Only the oxidizing valves had the problem, and no problems were detected with the fuel or helium valves, according to Vollmer. Were the launch to occur, the stalled valves would affect the performance of the Starliner OMAC (Orbital Maneuvering and Attitude Control) and RCS (Reaction Control System). But as Stitch and Vollmer reminded reporters, the missiles do not allow them to be fired with a fuse in the closed position.

No timetable has been set for when the Starliner will finally launch, but Stich said the OFT-2 mission will “certainly” happen after the launch of NASA’s Lucy, a space probe that explores Jupiter’s Trojan asteroids. window for it The launch begins on October 16 and ends on November 7. Vollmer entered, saying it’s too soon to know if Starliner will launch this year, “but we hope as soon as possible.”

It’s a very frustrating and frustrating situation, no doubt. In the meantime, NASA will continue to rely on SpaceX’s Crew Dragon to deliver astronauts to the International Space Station.

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