While NASA and Boeing are focused on completing the first astronaut mission aboard the Starliner spacecraft early next month, everyone’s already wondering what happens next.
Boeing’s Starliner spacecraft was postponed again on Friday (June 21) from the end of its first mission to the International Space Station (ISS) carrying astronauts including NASA’s Butch Wilmore and Suni Williams. Team officials stressed that additional testing remains before separation. Starliner experienced a helium leak and thruster issues, leading to an extension of the Crew Flight Test (CFT) mission to 10 days after its originally scheduled June 5 launch. NASA and Boeing have not yet announced a return date for Starliner, saying only that it will return after a spacewalk on July 2.
The unexpected events on the test flight, the CFT, were in some ways expected. But a key milestone is coming up soon: Starliner is scheduled to launch its first operational mission to the ISS in early 2025. The spacecraft, known as Starliner 1, is expected to carry at least three astronauts to the ISS on a standard six-month mission.
NASA’s Steve Stich recently told reporters (before Friday’s latest delay) that Starliner 1’s certification timeline could be accelerated, but the focus right now is on safely completing the CFT.
“We do not intend to fly a mission like this again with a helium leak,” Stich, NASA’s commercial crew program manager, said in a conference call on June 18. That discussion is “expected to take place later this summer.” [to] Once the vehicle returns with its crew, we will identify all the work that lies ahead of us and then plan our way forward.”
Related: A thruster malfunction or helium leak wouldn’t stop Boeing’s Starliner astronaut test flight, but why would this happen?
Starliner’s first helium leak was discovered on the launch pad in early May, following an emergency shutdown due to a valve problem on the capsule’s United Launch Alliance Atlas V rocket. While the leak was not expected to immediately affect the launch, NASA and Boeing discovered a design vulnerability that could affect the capsule’s re-entry if a sufficient number of Starliner’s Reaction Control System (RCS) thrusters went offline. The team qualified additional re-entry modes in simulations with astronauts and re-approved Starliner for launch.
While the CFT left the launch pad without incident on June 5, Starliner experienced problems with five of its 28 RCS thrusters while docking to the ISS. The first docking attempt was aborted, but Starliner successfully docked a second time a few hours later. Four additional helium leaks also occurred after Starliner reached space. Work is currently underway, including fault tree analysis, to determine the root cause.
Starliner also had issues with its RCS thrusters during its first uncrewed docking with the ISS in May 2022, but that was likely due to a different issue, officials said in a June 18 briefing. The cause is still in the early stages of being determined.
Both NASA and Boeing have repeatedly stressed that schedule isn’t their number one priority with the CFT, and that the unexpected can always happen — a point echoed by the two astronauts who flew on the mission, both former U.S. Navy test pilots.
The mission team is using the extra time in space to understand how Starliner’s service module operates, as it contains most of the spacecraft’s fuel and power and will be discarded upon landing. The RCS thrusters now appear to be mostly functional, but the helium leak is “stable and less than the amount measured.” [before]”We’re excited to be working with Boeing on this exciting new program,” said Mark Nappi, vice president and program manager for Boeing’s commercial crew programs.
Remarkably, the CFT has achieved 77 of its initial 87 flight test objectives, with the remaining 10 to be evaluated during undocking and landing, he added.
Related: NASA considers potential impacts of helium leaks on Boeing’s Starliner astronaut test flights
Post-CFT work will include figuring out why the flight control system “reduces thrust and then deselects thrusters,” as astronauts encountered this month, Stich said. The “silver lining” of an extended mission is that it will allow data to be acquired in space that can’t be collected on the ground, potentially saving time troubleshooting later.
“My goal is to iron out any glitches in the system before we use this spacecraft to rotate crew members and bring them back again in six months,” Stich said. Some ideas are already floating around. For example, the mission team might change the “aggressiveness of the rendezvous profile” to make the thrusters burn a little less hard, so they’re not straining the thrusters.
“We intend to completely eliminate these issues that are interfering with flight,” he added. “The good thing about our situation is, as I said, we can fly a little longer and gather as much data as we can and fully understand these issues, or understand them as well as we can, and eliminate them. And our intention is to completely eliminate these issues.”
However, NASA and Boeing do not expect to need to conduct additional test flights to iron out any issues before Starliner is certified.
“We are treating these issues as learnings and making additional tweaks to the vehicle to [achieve] “This is a certification of our vehicle,” Nappi said. “I don’t think this is a flight safety issue that would require us to fly a drone to further demonstrate the system.”
Starliner 1 will include NASA astronauts Mike Finke and Scott Tingle, and Canadian Space Agency astronaut Josh Cutlick. The crew is well advanced in their training and have worked closely with the CFT. For example, Finke is a longtime Starliner astronaut and served as the CFT’s backup, while Cutlick served as the capsule’s communicator during the critical ascent phase of the test mission.
Starliner and SpaceX’s Dragon capsule are tasked with ferrying NASA-led crews of astronauts to the ISS. Both Boeing and SpaceX were awarded multibillion-dollar contracts in 2014 for taxi services that were originally scheduled to launch in 2017. However, technical and financial issues have pushed back both companies’ timelines.
SpaceX borrowed the design from its Dragon robotic cargo spacecraft, which has been in operation since 2012 and achieved its first crewed flight in 2020. Starliner is a new spacecraft and has encountered additional development issues that often arise with complex new aerospace projects.
The path to the CFT was delayed after the first uncrewed test failed to reach the ISS due to technical issues in December 2019. A second uncrewed mission was successful in 2022, but further issues with Starliner were found in 2023, including the loading of parachutes and flammable tape on many of the capsule’s wiring.