This document summarizes the challenges and future plans for Boeing’s Starliner program, a spacecraft designed for NASA to transport astronauts to the International Space Station (ISS). The program has faced significant technical issues, leading to a revised strategy focusing on safety and system validation.
Genesis of the Starliner Program and Early Setbacks
The Starliner program aims to provide reliable human spaceflight capabilities, a complex endeavor marked by technological and engineering challenges. The program’s journey has been complicated by a series of critical issues, leading to its current phase: an uncrewed cargo flight.
Orbital Flight Test 1 (OFT-1) – December 2019: A Rocky Start
The initial uncrewed test flight, OFT-1, encountered severe problems that highlighted significant flaws in the spacecraft’s systems.
- Critical Software Errors: A major flaw in the Mission Elapsed Timer caused excessive fuel burn, preventing rendezvous and docking with the ISS.
- Re-entry Risk: Another software defect, if uncorrected, could have led to vehicle loss during re-entry.
- Thruster Issues: Thrusters were affected by overuse due to the timer error.
- Outcome: This “partial failure” necessitated a second uncrewed test flight.
Orbital Flight Test 2 (OFT-2) – May 2022: Persistent Glitches
- Launch Delays: Issues with oxidizer isolation valves being stuck caused launch delays.
- Propulsion System Glitches: Two thrusters failed during the orbital insertion burn, though backup systems compensated.
- Outcome: While the mission successfully docked with the ISS, recurring propulsion system issues signaled deeper, systemic problems.
The Crew Flight Test (CFT) Debacle – 2024: A Nightmare Mission
The Crew Flight Test (CFT) in 2024, carrying NASA astronauts Butch Wilmore and Sunita Williams, was intended to certify Starliner for regular crew rotation missions. However, it encountered significant problems:
- Cascading Thruster Failures: Multiple thruster failures occurred during the approach and docking with the ISS.
- Persistent Helium Leaks: Leaks were detected in the spacecraft’s service module.
- Manual Intervention: Docking was achieved through manual control and multiple thruster resets.
- NASA’s Decision: Due to the severity of the anomalies, NASA deemed the spacecraft unsafe for the astronauts’ return.
- Astronaut Return: Wilmore and Williams remained on the ISS for over nine months and returned to Earth aboard a SpaceX Crew Dragon capsule in March 2025.
- Pre-mission Concerns: Prior to CFT, concerns about flammable tape on wiring harnesses and insufficient parachute strength had already caused significant delays.
Contract Modifications and the Path to Starliner-1
In response to the persistent issues and to prioritize astronaut safety, NASA and Boeing have modified their Commercial Crew Program contract:
- Reduced Crewed Flights: The number of planned Starliner crewed flights has been reduced from six to four, with two additional flights designated as options.
- Starliner-1 Reconfiguration: The next Starliner mission, designated Starliner-1, has been reconfigured as a cargo-only flight.
- Target Launch Date: Starliner-1 is targeted for no earlier than April 2026.
- Mission Objective: This uncrewed mission will rigorously test propulsion system modifications and other fixes before any future crewed flights.
Financial Impact:
Boeing has publicly acknowledged over $2 billion in losses on its fixed-price contract due to cost overruns and delays.
Objectives of the Uncrewed Starliner-1 Cargo Mission
The Starliner-1 cargo mission has several critical objectives:
- Deliver Essential Cargo to the ISS: Transport necessary supplies, scientific experiments, and hardware to the ISS.
- In-flight Validation of System Upgrades: Rigorously test and validate revamped propulsion systems during launch, orbital maneuvers, docking, and re-entry. This includes testing design changes for helium leaks and degraded thruster valve seals.
- Address Propulsion System Issues: Conduct robust in-flight testing of corrective actions for repeated thruster failures and helium leaks, building on extensive ground testing.
Certification Prerequisite:
- A successful Starliner-1 mission is essential for NASA to certify the spacecraft for routine crewed operations.
- If successful, future crewed Starliner flights could resume as early as 2027.
- The aerospace safety advisory panel has commended NASA’s safety culture in handling CFT anomalies.
About the Author
