Fifth helium leak detected on Starliner

WASHINGTON — NASA confirmed that Boeing’s CST-100 Starliner spacecraft has suffered a fifth, though minor, helium leak in its propulsion system as engineers work to organize the automobile for its return to Earth subsequent week.

In a June 10 assertion, NASA talked about that spacecraft groups had been analyzing “what impacts, if any, 5 small leaks within the service module helium manifolds would have on the rest of the mission.” That was the primary reference to there being 5 leaks within the spacecraft; NASA had talked about there have been 4 in a briefing hours after the spacecraft’s June 6 docking with the Worldwide Area Station.

In a June 11 assertion to SpaceNews, NASA spokesperson Josh Finch mentioned the fifth leak was detected across the time of that post-docking briefing. “The leak is significantly smaller than the others and has been recorded at 1.7 psi [pounds per square inch] per minute,” he mentioned.

NASA was conscious of 1 leak on the time of Starliner’s June 5 launch, having been detected shortly after a scrubbed launch try Might 6. On the time of launch, NASA and Boeing officers thought-about {that a} one-off downside, possible attributable to a defect in a seal. Nonetheless, hours after launch controllers mentioned they’d detected two extra leaks, certainly one of which was comparatively giant at 395 psi per minute, mentioned Steve Stich, NASA industrial crew program supervisor, on the briefing.

A fourth leak was discovered after docking, though it was a lot smaller at 7.5 psi per minute. “What we have to do over the subsequent few days is check out the leak fee there and work out what we go do relative to the remainder of the mission,” Stich mentioned on the briefing.

NASA closed the helium manifolds within the propulsion system after docking to cease the leaks, though they must be opened to make use of the spacecraft’s thrusters for undocking and deorbit maneuvers. NASA mentioned June 10 that engineers estimate that Starliner has sufficient helium to help 70 hours of flight operations, whereas solely seven hours is required for Starliner to return to Earth.

Along with the helium leaks, engineers are finding out one response management system (RCS) thruster that shut down through the spacecraft’s flight to the ISS. 4 different thrusters had been turned off by flight software program however later reenabled. An RCS oxidizer isolation valve in Starliner’s service module can also be not correctly closed.

“We’ve got the industrial crew program, Boeing, ISS groups all built-in, working very nicely collectively to be able to provide you with a ahead plan for getting us in one of the best posture for that undock and reentry,” Dina Contella, NASA ISS deputy program supervisor, mentioned at a June 11 briefing a couple of collection of upcoming spacewalks on the ISS. “The groups are nonetheless working by what are one of the best methods to go about testing and making ready for undock and reentry.”

These groups have a while to finish that work. NASA had initially scheduled a June 14 undocking for Starliner, however NASA mentioned June 9 it was delaying the undocking to no sooner than June 18. That delay was to keep away from a battle with a June 13 ISS spacewalk, or EVA, by NASA astronauts Tracy Dyson and Matt Dominick.

“To have it again to again, had been we had an EVA adopted by undock, was not probably the most handy,” Contella mentioned. There are undocking alternatives each few days, ruled by the orbital mechanics that arrange a touchdown within the southwestern United States.

The 2 NASA astronauts who flew Starliner to the ISS, Butch Wilmore and Suni Williams, have been busy each conducting exams of Starliner whereas on the station whereas additionally performing different work, equivalent to science experiments. “Butch and Suni are an additional set of arms,” she mentioned, notably as different ISS crewmembers put together for the upcoming spacewalks. “Having Butch and Suni out there to carry out some key essential science has been excellent.”

Wilmore and Williams have publicly praised the efficiency of the spacecraft. “The spacecraft was exact, extra so than I might have anticipated. We may cease on a dime, so to talk,” mentioned Wilmore throughout a June 10 name with NASA management, discussing how the spacecraft maneuvered.

“Our skilled check pilots have been overwhelmingly optimistic of their flight on Starliner, and we are able to’t wait to study extra from them and the flight knowledge to proceed bettering the automobile,” Mark Nappi, Boeing vice chairman and industrial crew program supervisor, mentioned of the astronauts in a June 11 assertion.

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