Starliner report: Investigation reveals thruster flaws and schedule pressure

Canadian Space Agency astronaut Josh Kutryk was supposed to be on the first operational Boeing Starliner flight following the Crew Flight Test launch of June 2024, with NASA astronauts Butch Wilmore and Suni Williams.

But as we all remember, CFT’s Starliner had thruster issues on its way to the ISS (following on thruster issues from two previous uncrewed efforts). NASA and Boeing were unable to address everything on-orbit despite months of evaluation. Starliner returned autonomously in September 2024 and the two astronauts, switched to a SpaceX Crew Dragon, in March 2025.

Nearly a year after their return, NASA released a 300-page report concerning the CFT investigation, dated Feb. 5 and with some redactions (said to be due to ITAR requirements or contractor requests). But the overall message from new NASA administrator Jared Isaacman was the issues were serious, and that the agency will not proceed with any more Starliner flights until and if the spacecraft is technically ready for it.

Starliner’s next (uncrewed) test is scheduled for April, but Isaacman said he is prepared to push that date if necessary. “What we don’t want to do is perpetuate past problems by establishing endless target launch dates that we were unable to meet,” Isaacman said during a livestreamed press conference Thursday, Feb. 19, 2026.

The Starliner -1 crew has been largely reassigned to other flights; Kutryk’s next opportunity has not yet been released. And while CFT was always seen as a developmental effort, the report (and the agency comments at the press conference) indicated that the mission put the astronauts and spacecraft at undue risk, either as a Type A incident or a high-visibility close call.

“The path we took did not reflect NASA at our best,” Isaacman said. “There is no expectation of perfection in missions as challenging as those that we are entrusted to undertake. Even with our best efforts, and programs like CCP [commercial crew program] that have seen great success, mistakes will occur. What defines us is whether we learn from them, improve because of them, and strengthen confidence across this workforce and the nation that we serve. This requires transparency and accountability.”

The report’s root causes of CFT’s issues noted that NASA’s “hands-off contract approach limited insight into the Starliner’s development.” Meanwhile, “Boeing’s inadequate systems engineering and reliance on subcontractors without sufficient oversight created gaps in hardware qualification. NASA CCP’s culture prioritized provider success over technical rigor.”

As with the investigations into the Challenger and Columbia fatal disasters of 1986 and 2003, schedule pressure was also cited in the executive summary. “Persistent proximity to launch over several years created a high-stress environment, dictated a restrictive risk reduction initiative, and contributed to degraded trust with the workforce and overall fatigue,” the investigation stated.

The lessons learned included:

• Having more representative qualification testing for mission environments;
• Obtaining better telemetry sample rates to make it easier to detect and resolve anomalies;
• Performing better fault tolerance and hazard analysis;of contractor and based on mission safety, especially on critical areas of the mission – regardless of any past success. He said the situation points to “some lost muscle memory on on our on our engineering skills, so that we can look at situations again, regardless of contractor, and say – what this is?”

That said, the NASA administrator directly praised the actions of Mission Control and the crew during the difficult docking. “The controllers and the crew performed with extraordinary professionalism. Flight rules were appropriately challenged. Control was recovered and docking was achieved,” Isaacman said.

“It is worth restating what should be obvious at that moment: had different decisions been made, had thrusters not been recovered, or had docking been unsuccessful. the outcome of this mission could have been very, very different,” he continued. “The astronauts did remain safely aboard the International Space Station while they were advocating for data, for more testing and for leadership engagement necessary to complete their mission safely.”

When asked about any worries with oversight over SpaceX, Isaacman added that the approach to a careful program should be independent of contractor and based on mission safety, especially on critical areas of the mission – regardless of any past success. He said the situation points to “some lost muscle memory on on our on our engineering skills, so that we can look at situations again, regardless of contractor, and say – what this is?”

Meanwhile, another CSA astronaut – Jeremy Hansen – is about to climb on the Boeing-made Space Launch System rocket for Artemis 2, along with three NASA astronauts. The tanking for Artemis 2’s wet dress rehearsal was ongoing during the press conference; results and a determination of launch date could come as soon as today, as NASA plans a separate press conference at 11 a.m. EST.

NASA officials at Thursday’s conference emphasized the approach is different for SLS than Starliner: namely, NASA owns a lot of the design and the assembly of the vehicle and has more direct oversight over subcontractors. Starliner, by contrast, was supposed to be more of a service contract.

That said, based on the report insights there will surely be programmatic changes made at NASA based on what happened with CFT. Here are the key technical and organizational anomalies, in the report’s words.

Key Technical Anomalies

• Service Module (SM) RCS Thruster Anomaly: Five thrusters triggered fail off FDIR during ISS rendezvous resulting in a temporary loss of 6 Degrees of Freedom (6DOF) control. In-situ troubleshooting recovered four of five jets, enabling docking. Manual piloting did not specifically contribute to thrusters triggering their fail-off FDIR.
  • Most probable proximate (direct) causes and contributing factors:
    • Two-phase oxidizer flow (vaporization and cavitation)
    • Teflon poppet extrusion in oxidizer valves, restricting flow
    • Mechanical demand from GNC firing requests
• Crew Module (CM) RCS Jet Failure: A thruster failed to fire during descent, reducing the system to zero fault tolerance.
  • Leading theory: Corrosion from carbazic acid formed by residual propellant and CO₂
• Helium Manifold Leaks: Seven of eight SM helium manifolds leaked during the mission.
  • Most probable proximate (direct) cause and contributing factor:
    • Material incompatibility of seals with oxidizer, leading to degradation and leaks
    • O-ring sizing and poor gland fill/squeeze tolerances
• Deorbit Capability Fault Tolerance: The propulsion system lacked required two-fault tolerance for deorbit burns, which was a design flaw present since early development but not identified until CFT pre-launch.

Near-Real Time Cultural and Organizational Findings

• Decision Authority: Overlapping roles between NASA’s CCP, ISSP, and Boeing led to unclear governance.
• Erosion of Trust: Mistrust between NASA and Boeing was intensified by selective data sharing, perceived favoritism, and inconsistent transparency. NASA teams outside CCP felt excluded from critical decisions, while CCP felt overwhelmed by external input.
• Leadership Approach: CCP and Boeing leadership were perceived as overly risk-tolerant and dismissive of dissenting views. A risk-acceptance posture created division and undermined confidence in the decision making process.
• Team Dynamics and Communication: The mission was marked by chaotic meeting schedules, unclear roles, and communication breakdowns. Survey data shows low effectiveness ratings in team dynamics and organizational structure.
• Cultural Divergence: NASA’s traditional culture of technical rigor clashed with the commercial model’s emphasis on provider autonomy.