by While NASA and Boeing are focused on completing the first astronaut mission aboard the Starliner spacecraft early next month, what will happen next is already on everyone’s mind.
The Boeing Starliner capsule was delayed again on Friday (June 21) to complete its first International Space Station (ISS) mission with astronauts, including NASA crew Butch Wilmore and Suni Williams. Further testing is still ahead of release, team officials stressed; Starliner suffered a helium leak and thruster issues that extended its Crew Flight Test (CFT) mission from the originally planned 10 days after the June 5 launch. NASA and Boeing have not yet announced a return date for Starliner, saying it will only happen after the July 2 spacewalk.
As a test flight, the unexpected on CFT was in a way, expected. But an important milestone is quickly approaching: Starliner was expected to begin its first operational mission to the ISS in early 2025. Called Starliner-1, it is expected to carry at least three astronauts to the ISS for a typical six-month mission. .
NASA’s Steve Stich told reporters recently (before the latest delay on Friday) that the certification timeline for Starliner-1 could shift to the right, but the focus right now is bringing CFT to a safe conclusion.
“We’re not going to fly another mission like this with the helium leaks,” Stich, manager of NASA’s Commercial Crew Program, said during a June 18 teleconference. That discussion will come “later this summer, [to] lay out all the work ahead of us after the vehicle comes back with the team, and then figure out what the path forward is.”
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The first Starliner helium leak was found on the launch pad in early May, after scrubbing due to a valve issue with the capsule’s United Launch Alliance Atlas V rocket. The leak was not considered an immediate threat to launch, but NASA and Boeing revealed a design vulnerability where many of the Starliner’s reaction control system (RCS) thrusters could go offline, disrupting the capsule’s re-entry. The team confirmed an additional reentry method in simulations with the astronauts, before re-authorizing Starliner for launch.
CFT reached the pad without issue on June 5, but Starliner experienced problems with five of its 28 RCS thrusters on its way to the ISS for launch. The first attempt at the bay was aborted, but Starliner managed to achieve a second docking a few hours later. Four new helium leaks also emerged after Starliner reached space; fault tree analysis and other work is still underway to determine the root cause.
Starliner also experienced RCS thruster issues during its first uncrewed ISS docking in May 2022, but those appear to be due to a separate problem, officials said during the June 18 briefing. Learning why is still at an early stage.
Both NASA and Boeing have repeatedly stressed that timelines are not the priority at CFT, and that unpredictable things can always happen. The mission’s two astronauts, former US Navy test pilots, have said the same thing.
The mission team is using the extra time in space to understand how the Starliner service module is behaving, as it contains most of the spacecraft’s fuel and power and will be discarded during landing. The RCS thrusters seem to be mostly working now, although the helium leaks are “stable and less than measured [before],” according to Mark Nappi, Boeing’s vice president and commercial crew program manager.
In particular, CFT has achieved 77 of the original 87 flight test objectives; the last 10 will be evaluated during undocking and landing, he said.
Related: NASA weighs possible impact of helium leak and more on Boeing Starliner astronaut test flight
Work after CFT will include trying to understand what “causes the thrusters to have low thrust and then deselect them” by flight control systems, as the astronauts encountered this month, Stich said. The “silver lining” of the extended mission is that it will allow teams to obtain data in space that could not be collected on the ground, which could save time in troubleshooting later.
“My goal is to get the quirks … out of the system before we get to the stage where we’re going to be using this vehicle to rotate crew members and then bring them back at the end of the six months,” Stich said. Some ideas are already coming to mind: for example, maybe mission teams will change the “aggressiveness of the rendezvous profile” so that the thrusters are not taxed, by firing them a little less.
“We fully intend to eliminate these, call them nuisances, for the flight,” he said. “The good thing about our situation is that we can stay up a little bit longer, as we talked about, and get as much detail as we can so that we can fully understand this, or understand as long as we can. , so we can eliminate it And we intend to eliminate these issues completely.”
NASA and Boeing, however, do not expect to need to fly additional test flights to work out the issues ahead of Starliner certification.
“We characterize these problems as learning, and further fine-tuning that we have to do on the vehicle, to [achieve] certification for our vehicle,” said Nappi.
Starliner-1 will carry NASA astronauts Mike Fincke and Scott Tingle, along with Canadian Space Agency astronaut Josh Kutryk. The team is well advanced in its training and working closely with CFT. Fincke is a longtime astronaut with Starliner and served as CFT backup, for example, and Kutryk served as capcom (capsule communicator) during the critical altitude phase of the test mission.
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SpaceX’s Starliner and Dragon capsule are tasked with ferrying NASA-led crews of astronauts to and from the ISS. Boeing and SpaceX received billion-dollar contracts in 2014 for taxi services that were originally expected in 2017. However, technical and funding issues have pushed back that timeline for both vendors.
SpaceX managed to borrow its design from its Dragon robotic cargo spacecraft, which has been operating since 2012, its first human flight in 2020. Starliner is a new spacecraft and encountered more development issues, which often arise with projects complex new aerospace.
The path to CFT was postponed after the first uncrewed test in December 2019 failed to reach the ISS due to technical glitches. A second uncrewed mission made it in 2022, but Starliner encountered more problems in 2023 with parachute loading and flammable tape on much of the capsule’s wiring.
