{"id":45168,"date":"2024-05-25T19:38:42","date_gmt":"2024-05-25T11:38:42","guid":{"rendered":"https:\/\/wp-productionenv-bjg9h2g2bgg5b8aa.southeastasia-01.azurewebsites.net\/news\/nasa-finds-more-issues-with-boeings-starliner-but-crew-launch-set-for-june-1\/"},"modified":"2024-05-25T19:38:42","modified_gmt":"2024-05-25T11:38:42","slug":"nasa-finds-more-issues-with-boeings-starliner-but-crew-launch-set-for-june-1","status":"publish","type":"post","link":"https:\/\/starpath.global\/news\/nasa-finds-more-issues-with-boeings-starliner-but-crew-launch-set-for-june-1\/","title":{"rendered":"NASA finds more issues with Boeing\u2019s Starliner, but crew launch set for June 1"},"content":{"rendered":"

Senior managers from NASA and Boeing told reporters on Friday that they plan to launch the first crew test flight of the Starliner spacecraft as soon as June 1, following several weeks of detailed analysis of a helium leak and a \u201cdesign vulnerability\u201d with the ship\u2019s propulsion system.<\/p>\n

Extensive data reviews over the last two-and-a-half weeks settled on a 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 for the Starliner test flight to the International Space Station, officials said.<\/p>\n

But engineers also found that an unlikely mix of technical failures in Starliner\u2019s propulsion system\u2014representing 0.77 percent of all possible failure modes, according to Boeing\u2019s program manager\u2014could prevent the spacecraft from conducting a deorbit burn at the end of the mission.<\/p>\n

\u201cAs we studied the helium leak, we also looked across the rest of the propulsion system, just to make sure we didn\u2019t have any other things that we should be concerned about,\u201d said Steve Stich, manager of NASA\u2019s commercial crew program, which awarded a $4.2 billion contract to Boeing in 2014 for development of the Starliner spacecraft.<\/p>\n

\u201cWe found a design vulnerability\u2026 in the prop [propulsion] system as we analyzed this particular helium leak, where for certain failure cases that are very remote, we didn\u2019t have the capability to execute the deorbit burn with redundancy,\u201d Stich said in a press conference Friday.<\/p>\n

These two problems, uncovered one after the other, have kept the Starliner test flight grounded to allow time for engineers to find workarounds. This is the first time astronauts will fly into orbit on a Starliner spacecraft, following two unpiloted demonstration missions in 2019 and 2022.<\/p>\n

,<\/p>\n

The Starliner program is running years behind schedule, primarily due to problems with the spacecraft\u2019s software, parachutes, and propulsion system, supplied by Aerojet Rocketdyne. Software woes cut short Starliner\u2019s first test flight in 2019 before it could dock at the International Space Station, and they forced Boeing to fly an unplanned second test flight to gain confidence that the spacecraft is safe enough for astronauts. NASA and Boeing delayed the second unpiloted test flight nearly a year to overcome an issue with corroded valves in the ship\u2019s propulsion system.<\/p>\n

Last year, just a couple of months before it was supposed to launch on the crew test flight, officials discovered a design problem with Starliner\u2019s parachutes and found that Boeing installed flammable tape inside the capsule\u2019s cockpit. After replacing all of the tape, Boeing\u2019s star-crossed Starliner finally appeared ready to fly on the long-delayed crew test flight from Cape Canaveral Space Force Station, Florida.<\/p>\n

NASA commander Butch Wilmore and pilot Suni Williams were strapped into their seats inside Starliner on May 6 when officials halted the countdown due to a faulty valve on the spacecraft\u2019s United Launch Alliance Atlas V rocket. ULA rolled the rocket back to its hangar to replace the valve, with an eye toward another launch attempt in mid-May.<\/p>\n

But ground teams detected the helium leak in Starliner\u2019s service module in the aftermath of the scrubbed countdown. After some initial troubleshooting, the leak rate grew to approximately 70 psi per minute. Since then, the leak rate has stabilized.<\/p>\n

\u201cThat gave us pause as the leak rate grew, and we wanted to understand what was causing that leak,\u201d Stich said.<\/p>\n

Small problem with big impacts<\/h2>\n

Boeing engineers traced the leak to a flange on a single reaction control system thruster in one of four doghouse-shaped propulsion pods on the Starliner service module. The spacecraft has 28 of these small control jets to point the spacecraft and make minor adjustments to its orbit. Helium, an inert gas, is not combustible and is used to pressurize the propulsion system and force hypergolic hydrazine and nitrogen tetroxide propellants through pipes leading to the craft\u2019s maneuvering thrusters.<\/p>\n

,<\/p>\n

The most likely culprit for the leak is a defect in a rubber seal about the size of a button on a shirt, at a point where two metal parts of the flange connect. \u201cThis particular leak, I don\u2019t think it implicates the design of the seal or the flange, it\u2019s just maybe a defective part,\u201d Stich said.<\/p>\n

\u201cThis is a high-pressure system, and helium is a very small, tiny molecule, and it tends to leak,\u201d he said.<\/p>\n

\n

\"\"<\/p>\n

The \u201cdoghouse\u201d structures around the circumference of Boeing\u2019s Starliner spacecraft are visible in this image taken last month as the capsule was lifted on top of its Atlas V rocket. Each doghouse has multiple thrusters.<\/p>\n

Credit:
\n United Launch Alliance<\/p>\n<\/figure>\n

Managers had two options to address the leak.<\/p>\n

In order to repair it, Boeing would need to remove the Starliner spacecraft from its Atlas V rocket and take it back to a nearby facility, where technicians would drain the service module of toxic propellants. There, workers could safely access the leaky seal and install a replacement. Boeing would then have to refill the spacecraft with propellant, reinstall it on the Atlas V rocket, and run the entire vehicle through another series of integrated mechanical and electrical tests. \u201cIt would be quite involved,\u201d said Mark Nappi, Boeing\u2019s vice president and program manager for Starliner.<\/p>\n

All this would probably take at least several months and could delay downstream flights to the International Space Station and future ULA missions stacked up behind the Starliner test flight.<\/p>\n

Instead, managers decided to take an \u201canalysis-based approach\u201d to understand the leak, Stich said. Part of this approach included a three-day pressure decay check on Starliner\u2019s propulsion system. Engineers detected no helium leaks elsewhere on the spacecraft.<\/p>\n

\u201cNot a safety-of-flight issue\u201d<\/h2>\n

Boeing and NASA experts also looked at what would happen if the existing leak worsened after launch.<\/p>\n

\u201cIf this seal completely blows out and we had just metal-to-metal contact, we know we can manage this,\u201d Nappi said. \u201cSo this is really not a safety-of-flight issue for ourselves, and we believe that we have a well-understood condition that we can manage.\u201d<\/p>\n

,<\/p>\n

Stich said the analysis showed that even if the defective seal failed completely, the spacecraft could handle such an event along with up to four additional helium leaks in other parts of the propulsion system. \u201cWith this kind of pressure, it doesn\u2019t take a very big defect to get these kinds of leak rates,\u201d Stich said. \u201cSo we think it\u2019s stable. That\u2019s why we think it\u2019ll be fine during ascent and in the rest of the flight.\u201d<\/p>\n

As engineers assessed the ramifications of the helium leak, they stumbled upon a design flaw that, in rare cases, could prevent the spacecraft from conducting a braking maneuver to re-enter the atmosphere and head for landing at the end of the mission. Boeing designed the spacecraft to perform the deorbit burn three different ways, either with two or four of the ship\u2019s more powerful maneuvering engines or with eight of the smaller reaction control system jets.<\/p>\n

Under the wrong set of circumstances, helium manifold failures on two adjacent doghouse propulsion pods could jeopardize Starliner\u2019s ability to execute the deorbit burn.<\/p>\n

\u201cIt\u2019s a pretty diabolical case, where you would lose two helium manifolds in two separate doghouses, and then they have to be next to each other,\u201d Stich said.<\/p>\n

In a matter of weeks, engineers devised a workaround. This new deorbit burn method would require just four reaction control system thrusters. Wilmore and Williams, back at their home base in Houston, tested the new backup mode in a Starliner simulator, according to Stich.<\/p>\n

Nappi, who took over management of the Starliner program in 2022, said he isn\u2019t concerned about the robustness of Boeing\u2019s review processes, which missed the design vulnerability in the run-up to the spacecraft\u2019s previous test flights and the first crew launch attempt earlier this month. The design issue also escaped NASA\u2019s oversight reviews.<\/p>\n

,<\/p>\n

\u201cWe have multiple redundancies in our system,\u201d Nappi said. \u201cWe have a case here that\u2019s extremely remote that we missed. And if there are more out there, they\u2019re going to be in that same category of extremely remote.\u201d<\/p>\n

With an understanding of the leak and a solution in place for the design problem, NASA and Boeing are moving forward with another Starliner launch attempt June 1. There are additional launch opportunities June 2, June 5, and June 6.<\/p>\n

\u201cThe teams went under some pretty intense scrutiny to be able to explain the issues that we were finding,\u201d Nappi said. \u201cThey got pressure-tested on their conclusions, and then eventually the community bought into our flight rationale and the actions.\u201d<\/p>\n

Wilmore and Williams, still in pre-flight medical quarantine, will return to Florida on Tuesday for final launch preparations. NASA officials will convene a flight test readiness review Wednesday, and if they give the green light, ULA will roll the Atlas V rocket and Starliner spacecraft back to the launch pad on Thursday, May 30.<\/p>\n

The Starliner team will check the status of the helium leak during the countdown on June 1. If the leak is unchanged, the astronauts will take their seats inside the cockpit to await liftoff at 12:25 pm EDT (16:25 UTC).<\/p>\n

Wilmore and Williams will spend at least eight days at the space station before returning to Earth for a parachute-assisted landing in the southwestern United States, likely at White Sands, New Mexico.<\/p>\n

Assuming a smooth test flight, NASA hopes to formally clear Starliner for six-month crew rotation flights to the space station next year. NASA will alternate between Boeing\u2019s crew capsule and SpaceX\u2019s Crew Dragon, which has been flying astronauts since 2020, for crew missions to the station.<\/p>\n

But NASA and Boeing officials said they are looking at long-term software and hardware fixes to address the newly discovered design vulnerability in the propulsion system. It\u2019s not yet clear how that might affect the schedule for operational Starliner missions.<\/p>\n","protected":false},"excerpt":{"rendered":"

Senior managers from NASA and Boeing told reporters on Friday that they plan to launch the first crew test flight of the Starliner spacecraft as soon as June 1, following several weeks of detailed analysis of a helium leak and a \u201cdesign vulnerability\u201d with the ship\u2019s propulsion system. Extensive data reviews over the last two-and-a-half […]<\/p>\n","protected":false},"author":1,"featured_media":45169,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":"","_links_to":"","_links_to_target":""},"categories":[2],"tags":[7758,670,524,190,1306,750],"class_list":["post-45168","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news","tag-atlas-v","tag-boeing","tag-commercial-crew","tag-nasa","tag-starliner","tag-united-launch-alliance"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/45168"}],"collection":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/comments?post=45168"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/45168\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media\/45169"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=45168"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=45168"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=45168"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}