Boeing’s first crewed Starliner mission has been in orbit for more than a month and still has no return date.
The Starliner lifted off on June 5 for a Crew Flight Test (CFT), carrying NASA astronauts Butch Wilmore and Suni Williams to the International Space Station (ISS) for a planned one-week stay. However, the capsule experienced helium leaks and nozzle problems during the journey, and engineers are still investigating what caused them – meaning the Starliner has not yet been cleared for liftoff.
“We’re taking time on the ground to go through all the data before we decide on a return opportunity,” Steve Stich, NASA’s commercial crew program manager, said during a press conference Wednesday (July 10).
However, NASA, Boeing and the two CFT astronauts still have confidence in the Starliner. During a separate media event Wednesday, Wilmore, for example, praised the capsule’s capabilities in orbit during operational checks. “The spacecraft performed incredibly well,” he said.
Wilmore also discussed the problems with the Starliner’s Reaction Control System (RCS) thrusters during the ISS pursuit and how the mission dealt with them.
“We lost an RCS jet and then another, and then you could tell the thrust, handling and capabilities were degraded,” he explained. “Fortunately, we trained and got certified for manual controls, so we took over manual controls for over an hour.”
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After arriving at the ISS on June 6, Wilmore and Williams joined the crew of the station’s Expedition 71, which Williams says is now unofficially called “Expedition 71+”. Wilmore and Williams took on day-to-day maintenance and science experiments, and managed to fill the gap on several backlogs on the station. During their mission, the duo also continued to check the Starliner’s many systems and anomalies encountered, which are also being investigated by Boeing engineers back on Earth to determine their cause.
Stich emphasized a careful approach to data analysis and replication of the spacecraft’s thruster problems during testing at NASA’s White Sands Test Facility in New Mexico. One of the advantages of the ISS, he said, is its ability to serve as a temporary orbital “hangar,” providing a unique opportunity to understand the Starliner’s long-term performance in space before disconnection.
In addition to problems with the nozzles, several helium leaks were identified in the Starliner capsule. “There were a number of specific events that were identified from both the helium anomalies and the thruster,” Mark Nappi, Boeing vice president and commercial crew program manager, said Wednesday. “He’s only a little over 30 [actions]more than half of which are currently closed.”
“As for the helium leak, we hope to bring that to the Starliner mission management team for final resolution later this week,” Stich said. Despite these problems, agency officials said the spacecraft is intended to leave the ISS in the event of an emergency, with all but one of the 28 RCS thrusters cleared for use on reentry into Earth’s atmosphere.
The decision to extend the Starliner’s mission also gave the ground teams additional time they hadn’t expected. According to Nappi, Amy Decker of Starliner’s chief engineer’s office says the extra data they’re getting is “AWESOME, in all sizes.”
“The more time you have to get more data,” Nappi said, “the more excitement.” [the engineers get].”
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The very latest Starliner could return with Wilmore and Williams, according to Stich, in mid-August.
“The big driver is the handover that happens between Crew-8 and Crew-9, which is in mid-August,” Stich said, referring to SpaceX’s two astronaut missions to the ISS. “So… a few days before that [Crew-9] opportunity to launch, we’d need to get Butch and Suni home on the Starliner.”
Ideally, however, they will come home earlier. “We’re really working to try to track the data and figure out when the earliest it’s possible to focus on disconnection and landing,” Stich said. “I think some of the data is optimistic that maybe it will be before the end of July, but we’ll just take the data one step at a time and see when the right opportunity is to release.”
“We have a lot of confidence in the thrusters as they are today,” Nappi said, referring to the in-orbit test firing of the thrusters that the Starliner performed while docked at the ISS.
“We’re just taking our time to make sure we’ve looked under every rock and every stone and to make sure nothing else surprises us,” Stich added in response.
CFT follows two previous unmanned Starliner missions to the ISS. The first, in December 2019, failed to reach the lab in orbit after experiencing a series of malfunctions. The second, in May 2022, docked successfully but also experienced problems with the thrusters.
“We knew we could learn from this flight test,” Nappi said. “We learned a lot from how the hardware works, how our processes work and how we can improve.”
As of now, “there is one funnel that was producing very low thrust that we would disable for the rest of the flight,” Stich explained. The extended stay on the ISS also helps teams prepare the spacecraft for future operational astronaut missions, expected to last up to six months, starting with Starliner-1 sometime in 2025.
Tests at White Sands during CFT helped planners look ahead to the first operational mission and how to avoid similar problems with the jets.
According to Stich, the Starliner’s thrusters were fired more frequently than the engineers expected this time.
“What we’re trying to do at White Sands,” he said, “is to really replicate exactly what the pulses that the jets saw were, and then understand the heating effects from those pulses, and just to make sure that it doesn’t have any unintended consequences.” those pulses.”
Stich said he thinks there is a way to take what the teams observed with the jets during CFT and adjust their requirements for future rendezvous and docking maneuvers. “I think that’s the work ahead for Starliner-1,” he said.
As the CFT mission continues, the focus remains on ensuring a safe return for Wilmore and Williams. “The Starliner will ‘go’ back in an emergency,” confirmed Stich. The team is working on this process, including a return flight readiness check, to prepare for the eventual shutdown and landing of the Starliner.