Boeing Starliner malfunction potentially caused by humid Florida air, investigators say – .

Boeing Starliner malfunction potentially caused by humid Florida air, investigators say – .

Starliner inside the vertical integration facility.

Starliner inside the vertical integration facility.
Image: Boeing

Boeing and NASA engineers are looking into the root cause of a technical glitch that led to the cancellation of a Starliner test launch. A promising theory suggests that moisture has entered the spacecraft’s propulsion system, causing critical valves to block. As to how this moisture got in, however, is now a question that needs an answer.

“The time has come for us to bring Starliner back to the factory,” John Vollmer, vice president and program director of Boeing’s commercial crew program, said solemnly in a conference call hosted by NASA. today. The spacecraft will be lowered from the top of the United Launch Alliance Atlas V rocket and transported to the Boeing factory at Kennedy Space Center, which once served as the Space Shuttle’s processing facility.

Starliner has been parked inside ULA’s vertical integration facility for over a week now as engineers from Boeing and NASA attempted to “restore functionality”To 13 oxidizer valves that did not open during the countdown to launch on August 3. This was to be the second unmanned test flight of the CST-100 Starliner and its first flight since late 2019. For the first test, Starliner actually managed to take off and into space, but a software failure prevented it from reaching its intended destination, the International Space Station. Boeing made its way through many fixes over the past year and a half, leading to the now indefinitely postponed Orbital Flight Test-2 (OFT-2).

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

A United Launch Alliance Atlas V rocket with Boeing’s CST-100 Starliner spacecraft at Cape Canaveral Space Launch Complex 41 on August 2, 2021.
Image: NASA/Joël Kowsky

“We’re not frustrated,” Kathryn Lueders, NASA’s associate administrator for exploration and human operations, told reporters on the teleconference. “We are just sad,” she said, adding that “we will learn from it.”

Lueders was the designated optionmist of the press conference, consistently describing the situation in terms of half-full glass and refraining from directing critical remarks to NASA’s business partner Boeing.

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

Specialists were able to move seven of the stuck valves on August 10 and nine on August 13. All but four of the 13 valves have been recovered, but after “doing everything we could on them” Boeing “has finally decided to stop and go back to the factory” where engineers will continue to fix the issues. problems, as Vollmer explained. The plan, he said, is to take Starliner apart as little as possible. like possible to minimize adjustments to the current configuration.

Vollmer, with Steve Stich, NASA’s Commercial Crew Program Manager, shared new details on the issue and what may have gone wrong.

Starliner is equipped with 24 oxidation valves, 24 fuel valves and 16 helium valves. These valves isolate the thrusters from the propellant tanks and must be opened before launch. The “most likely root cause” of the problem, Vollmer said, is that moisture has somehow seeped into the dry side of the oxidation valves, causing nitric acid to form. According to this theory, the ensuing corrosion friction caused the 13 valves to jam. Moisture could have entered the system during the assembly of the Starliner, during pre-launch checks or while the spacecraft was on the launch pad, as Stich explained.

Vollmer said it was possible for atmospheric moisture to have crept into the system and entered the valve covers. Splashes of water from an intense storm that swept over the launch pad a day before the scheduled launch are unlikely to be the source of this moisture, he added. It is not known if a redesign is necessary or whether preventative measures will do the trick, but it’s “definitely something that needs to be resolved,” Vollmer said.

“We use Teflon gaskets which can resist NTO [nitrogen tetroxide], which is a very corrosive oxidant, ”Vollmer said. “We know there is permeation through this seal,” so specialists will have to “go back to see if the ambient moisture was retained during assembly” of the Starliner, or if something else has. caused moisture to seep into the valves afterwards, he said. .

To which he added: “There is a lot on the fault tree, and a lot on the fault tree that interact with each other, but so far it is the main candidate for the cause of the failure.

Vollmer said the valves were checked five weeks before launch and “were working perfectly”. Additionally, it is the same design used in the Orbital-1 Flight Test and on the Wafer Abandon Test Vehicles. Because rockets are launched all the time from Florida, engineers will need to figure out why moisture should suddenly be a problem, if that’s the cause, he said. According to Vollmer, only the oxidant valves encountered the problem and no problems were found with the fuel or helium valves. Had a launch taken place, the stuck valves would have affected the performance of Starliner’s OMAC (Orbital Maneuver and Attitude Control) and RCS (Reaction Control System) thrusters. But as Stich and Vollmer reminded reporters, rockets are not allowed to be launched with the valves in the closed position.

No timeline has been given as to when Starliner could finally take off, but Stich has said the OFT-2 mission will happen “definitely” after the launch of NASA’s Lucy, a space probe that will explore Jupiter’s Trojan asteroids. . Window for that the launch begins October 16 and ends November 7. Vollmer intervened, saying it was too early to say if Starliner will launch this year, “but hopefully sooner. ”

It is a very disheartening and frustrating situation, without a doubt. In the meantime, NASA will continue to rely on SpaceX’s Crew Dragon to transport its astronauts to the ISS.

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