Hard to believe, but it’s been almost two and a six months since Boeing’s first failed test of its Starliner CST-100 spacecraft. Yeah, it’s been a minute, so here’s a recap of the last 28 tumultuous months, and how Boeing could finally succeed in providing a viable commercial crew vehicle for NASA.
The previous two tests, one in 2019 (Orbital Flight Test-1) and the other last year (Orbital Flight Test-2), did not go well, to say the least. . During the first test, the capsule went into orbit but then encountered a problem and never reached the space station. In the second, blocked the valves held Starliner to the ground. Boeing is developing this capsule under a $4.3 billion NASA contract Commercial Crew Program, but it is very late. The pressure is now on.
In preparation for this second attempt at OFT-2, the Starliner capsule currently sits atop a United Launch Alliance Atlas V rocket, which is scheduled to launch from Space Launch Complex-41 at Cape Canaveral Space Force Station at 6:54 p.m. EDT Thursday, May 19. If all goes as planned, the uncrewed CST-100 will dock with the International Space Station on Friday, May 20 at 7:10 p.m. EDT. Starliner OFT-2 is packed with approximately 500 pounds of cargo (mostly food), and the plan is to return 600 pound sterling of cargo to Earth.
Recent precedent being what it is, this route is hardly a certainty. The issues that plagued this program ran the gamut, from hardware issues and software anomalies to shoddy processes and organizational shortcomings. from Boeing shortcomings as a NASA partner have been on full display over the past few years and amplified by SpaceX’s accomplishments, NASA’s other commercial crew partner. Elon Musk’s Crew Dragon has been ferrying astronauts to the ISS and back home for two years now.
The launch of Boeing’s OFT-1 mission on December 20, 2019 was a harbinger that things weren’t quite right. The capsule managed to reach space, but a software automation glitch caused the spacecraft to burn excess fuel, preventing it from reaching its target, the ISS. A subsequent investigation implicated a faulty elapsed mission timer, which caused the Starliner and rocket schedules to become out of sync. As a result, Starliner miscalculated its location in space, triggering the unfortunate fuel burn. Investigators also discovered a coding error that could have led to an insecure service module separation sequence. As if it waswas not enough, space-to-ground communications were unexpectedly lost during the OFT-1 test.
The botched test led a NASA-Boeing independent review team to publish 80 recommendations to Boeing, a long to-do list that included improved testing and modeling, new development requirements, software updates, organizational changes and operational adjustments. The subsequent effort to address these recommendations resulted in a 1.5 year delay in the Starliner program.
On August 3, 2021, Boeing was ready to perform Starliner’s second test, the OFT-2 mission, but the Atlas V rocket never left the launch pad due to “unexpected valve position indications” in the capsule propulsion system. During the countdown, 13 of the 24 oxidizer valves, which “relate thrusters that allow abort and maneuvers in orbit“, got stuck in the closed position, forcing the team to abort the launch and to return to the Ease of Vertical Integration capsule for a closer inspection.
Engineers later determined that moisture had somehow penetrated the dry side of the oxidation valves, causing nitric acid to form, and the ensuing corrosion friction causing valve blockage. The engineers accused the humid florida air for thats unwanted moisture.
During a media conference call on May 3NASA Commercial Crew Program Manager Steve Stich said the issue “has been resolved” and OFT-2 is once again ready to continue. “It’s been a difficult eight months, I would say, but very rewarding in that we have resolved the issue with the oxidizer isolation valve,” he said.
Michelle Parker, vice president and deputy general manager of space and launch at Boeing, told reporters that “the spacecraft looks great” and “works great.” Boeing engineers were able to narrow down the root cause and implement measures to prevent a repeat, she explained. Parker said the team chose not to redesign the valves but instead putty and other components were added to keep moisture away. By “sealing the path of ambient humidity,” she said, the team hopes to prevent a recurrence. “If you remove moisture from the valve, you remove [chemical] reaction,” she said. The ground crew now cycles the valves every two days to ensure functionality, Parker added.
Asked if another failed test would trigger the end of the NASA-Boeing commercial crew contract, NASA ISS program manager Joel Montalbano said the space agency would continue to work with Boeing on the project and that there was no intention of stopping now. “I suspect we’ll learn from the test flight” and then “go fly the crewed flight and then do the post-certification missions,” he told reporters.
Indeed, a successful OFT-2 mission would pave the way for OFT-3, a crewed Starliner mission to the ISS. “We understand that we are going to learn a lot from OFT-2, and that will dictate the timing going forward, but we have a goal [to launch a crewed mission] at the end of this year,” Mark Nappi, Boeing program manager for the CST-100 Starliner mission, said at the May 3 press conference.
The problem with the valves, it seems, is not solved. Boeing is currently considering the possibility of redesigning the propulsion valves. “A redesign of the valve is definitely on the table”, Nappi Told journalists last Wednesday. “Once we get all the information we need, we will make that decision.” And like reported in Reuters, Boeing and Aerojet Rocketdyne are currently bickering over who is responsible for the faulty valves. Aerojet Rocketdyne and its attorneys say a cleaning chemical used by Boeing during ground testing caused the problem, a claim Boeing denies, according to Reuters. Boeing’s acknowledgment of a potential valve redesign and its blame game with Aerojet Rocketdyne bode ill just before OFT-2’s launch.
A crewed Starliner test launch later this year would be grand, but we better not get ahead of ourselves. ourselves. All eyes will be on Space Launch Complex-41 on May 19, in what is becoming one of the most anticipated and rushed launches of the year.