Boeing's CST-100 Starliner is a crewed spacecraft developed to ferry NASA astronauts to and from the International Space Station (ISS), competing directly with SpaceX's Crew Dragon. Originally contracted in 2014 under NASA's Commercial Crew Program, Starliner has been plagued by software errors, propulsion failures, and ballooning costs — culminating in a 2024 crewed test flight that left two astronauts stranded aboard the ISS for months before they returned home on a SpaceX capsule in early 2025.
What Is Boeing Starliner and Why Was It Built?
After NASA retired the Space Shuttle in 2011, the agency became wholly dependent on Russian Soyuz capsules to reach the ISS at roughly $90 million per seat. To end that reliance, NASA's Commercial Crew Transportation Capability (CCtCap) contracts — awarded in September 2014 — gave Boeing $4.2 billion and SpaceX $2.6 billion to develop independent crew vehicles. Starliner was designed to carry up to seven astronauts, re-enter the atmosphere under parachutes, and land on land using airbags — a first for a U.S. orbital crew capsule. Boeing brought deep spaceflight heritage from the Apollo Service Module and Space Shuttle programs, making it the favored choice of many NASA managers at the time of contract award.
What Went Wrong: A Timeline of Starliner's Major Failures
Starliner's troubles began long before it ever carried a crew. During its first uncrewed Orbital Flight Test (OFT-1) in December 2019, a software clock error caused the capsule to burn its thrusters at the wrong time, stranding it in the wrong orbit and preventing it from docking with the ISS at all. A second software bug discovered mid-flight could have caused a catastrophic collision. OFT-2, a re-do of the uncrewed test, finally succeeded in May 2022 after further delays caused by corroded propulsion valves. The first crewed flight — the Crew Flight Test (CFT) carrying NASA astronauts Butch Wilmore and Suni Williams — launched on June 5, 2024. What was planned as an eight-day stay stretched into months when five helium leaks and failures in 28 of the capsule's 28 maneuvering thrusters raised serious safety questions about the return journey. NASA ultimately decided in August 2024 that the risk was too high, and Starliner returned to Earth uncrewed on September 6, 2024. Wilmore and Williams eventually came home aboard SpaceX Crew Dragon on March 18, 2025, after spending roughly nine months on the ISS.
| Mission | Date | Outcome |
|---|---|---|
| OFT-1 (Uncrewed) | Dec 2019 | Software error — missed ISS, no docking |
| OFT-2 (Uncrewed) | May 2022 | Success — docked with ISS |
| Crew Flight Test (CFT) | Jun 2024 | Crew reached ISS; capsule returned uncrewed Sep 2024 |
| Wilmore & Williams return | Mar 2025 | Crew returned on SpaceX Crew Dragon |
What Does Starliner's Future Look Like for NASA?
Boeing has absorbed over $1.5 billion in cost overruns on the Starliner program with no additional NASA compensation, as the fixed-price contract shields taxpayers but punishes Boeing. As of early 2025, NASA has not committed to flying astronauts on Starliner again and is conducting a thorough review of the thruster and helium system failures. Boeing's aerospace division — already battered by 737 MAX crises and defense contract losses — faces pressure to either fix Starliner's technical issues or exit the commercial crew market entirely. SpaceX's Crew Dragon, which has completed multiple operational crew rotations without incident since 2020, now stands as NASA's primary crewed transport vehicle to the ISS.
