Overview
The CST-100 Starliner is a crew capsule developed by Boeing under NASA's Commercial Crew Programme (CCP), alongside SpaceX's Crew Dragon. Starliner is designed to carry up to 7 astronauts to the International Space Station, launching atop a ULA Atlas V rocket (and eventually Vulcan Centaur). However, Starliner's development has been marked by significant delays, software errors and thruster issues that have made it one of the most troubled spacecraft programmes in modern spaceflight.
Key Specifications
| Parameter | Value |
|---|---|
| Manufacturer | Boeing |
| Crew Capacity | Up to 7 (4 for NASA missions) |
| Diameter | 4.56 m (15 ft) |
| Height | 5.03 m (capsule + service module) |
| Mass | ~13,000 kg |
| Habitable Volume | 11 m³ |
| Launch Vehicle | Atlas V N22 / Vulcan Centaur |
| Launch Site | SLC-41, Cape Canaveral |
| Landing | Airbag-assisted land landing (western US) |
| Abort System | 4 × Launch Abort Engines (pusher configuration) |
| Reusability | Capsule designed for 10 flights |
Development History
OFT-1 (December 2019): The first uncrewed Orbital Flight Test failed to reach the ISS due to a mission elapsed timer software error that caused excessive thruster firings. A second critical software bug was discovered during the mission that could have caused a catastrophic collision between the capsule and service module during separation. The capsule returned safely but never reached the station.
OFT-2 (May 2022): The second uncrewed test reached the ISS successfully, but experienced thruster anomalies during approach and docking. Two of the capsule's orbital manoeuvring thrusters failed during flight.
CFT (Crew Flight Test, June 2024): The first crewed flight carried NASA astronauts Butch Wilmore and Suni Williams to the ISS. During approach, five of Starliner's 28 reaction control thrusters failed, and helium leaks were detected in the propulsion system. NASA ultimately decided the thruster issues posed too much risk for crew return. Wilmore and Williams remained on the ISS, and Starliner returned to Earth uncrewed in September 2024. The astronauts returned months later aboard a SpaceX Crew Dragon on the Crew-9 mission.
Mission Log
| Mission | Date | Type | Outcome |
|---|---|---|---|
| Pad Abort Test | Nov 2019 | Abort test | Partial success (1 of 3 parachutes failed) |
| OFT-1 | Dec 2019 | Uncrewed test | ❌ Failed to reach ISS (software error) |
| OFT-2 | May 2022 | Uncrewed test | ⚠️ Reached ISS; 2 thruster failures |
| CFT | Jun 2024 | Crewed test | ⚠️ Reached ISS; 5 thruster failures, helium leaks; crew returned via Dragon |
Land Landing
Unlike Dragon (which splashes down in the ocean), Starliner is designed for land landings using airbags deployed beneath the heat shield. This approach aims to reduce recovery costs and simplify capsule refurbishment for reuse. Landing sites are planned in the western United States (White Sands, New Mexico being the primary site).
Starliner vs Crew Dragon
| Parameter | Starliner | Crew Dragon |
|---|---|---|
| Crew | 4 (7 max) | 4 (7 max) |
| Diameter | 4.56 m | 4.0 m |
| Volume | 11 m³ | 9.3 m³ |
| Landing | Airbag land landing | Ocean splashdown |
| Abort | 4 × LAE (pusher) | 8 × SuperDraco (pusher) |
| Launch Vehicle | Atlas V / Vulcan | Falcon 9 |
| Reuse Target | 10 flights | 4+ proven |
| Operational Missions | 0 | 10+ |
| NASA Contract | $4.2 billion | $2.6 billion |
Programme Status
Following the CFT thruster and helium leak issues, the future of the Starliner programme is uncertain. Boeing has absorbed over $1.6 billion in cost overruns on the fixed-price CCP contract. NASA has expressed continued interest in maintaining two crew transport providers for redundancy, but operational Starliner crew rotation missions depend on resolving the propulsion system issues definitively. As of 2026, no further Starliner missions have been scheduled.
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Pick a mission profile and we'll rank the world's crewed and cargo spacecraft by suitability — capability, flight heritage, reusability and fit. A live calculation across our spacecraft catalogue, not a static list.
Anatomy & mission profile
- Crew7 max (4 typical)
- Pressurised vol11 m³
- Mass13,000 kg
- Launch vehicleAtlas V / Vulcan
- Abort system4× launch-abort engines (pusher)
- LandingAirbag-cushioned ground landing
Pressurised volume to scale
Approximate pressurised volume — a sense of how roomy each vehicle is for crew or cargo.
Starliner vs every crew & cargo spacecraft
| Spacecraft | Type | Crew | Cargo kg | Vol m³ | Reuse | Debut | Status |
|---|---|---|---|---|---|---|---|
| 🇺🇸 Starliner you are here | Crew capsule | 7 | — | 11 | ♻︎ Yes | 2019 | Under review |
| 🇺🇸 Crew Dragon | Crew capsule | 7 | — | 9.3 | ♻︎ Yes | 2020 | Operational |
| 🇺🇸 Cargo Dragon | Cargo spacecraft | — | 6,000 | 9.3 | ♻︎ Yes | 2020 | Operational |
| 🇺🇸 Dragon | Crew + cargo family | 7 | 6,000 | 9.3 | ♻︎ Yes | 2010 | Operational |
| 🇺🇸 Orion | Deep-space crew capsule | 4 | — | 19.6 | No | 2022 | Pre-operational |
| 🇷🇺 Soyuz MS | Crew capsule | 3 | — | 7.5 | No | 1967 | Operational |
| 🇨🇳 Shenzhou | Crew capsule | 3 | — | 7 | No | 2003 | Operational |
| 🇷🇺 Progress | Cargo spacecraft | — | 2,400 | 7.6 | No | 1978 | Operational |
| 🇨🇳 Tianzhou | Cargo spacecraft | — | 6,700 | 18.1 | No | 2017 | Operational |
| 🇺🇸 Cygnus | Cargo spacecraft | — | 3,750 | 27 | No | 2013 | Operational |
| 🇺🇸 Dream Chaser | Cargo spaceplane | — | 5,500 | 16 | ♻︎ Yes | Planned | In development |
| 🇺🇸 Starship HLS | Crewed lunar lander | 4 | 100,000 | 100 | ♻︎ Yes | Planned | In development |
| 🇯🇵 HTV-X | Cargo spacecraft | — | 5,850 | 30 | No | Planned | In development |
Tap any column to sort · crew = maximum seats, cargo = pressurised + unpressurised upmass · figures are best estimates as of 2026.
Track Starliner across Orbital Radar
Frequently Asked Questions
NASA astronauts Butch Wilmore and Suni Williams launched on Starliner CFT in June 2024 but could not return due to thruster failures and helium leaks. They remained on the ISS and returned months later aboard SpaceX Crew Dragon (Crew-9 mission).
As of 2026, Starliner has not been officially cancelled, but no further missions are scheduled. Boeing has absorbed over $1.6 billion in cost overruns. NASA continues to evaluate the programme's future.
Starliner is slightly larger and lands on land rather than water. However, Crew Dragon has completed 10+ operational missions while Starliner has completed zero. See the comparison table above.
It uses airbags beneath the heat shield for land landings at White Sands, New Mexico. This aims to reduce recovery costs and simplify refurbishment compared to ocean splashdown.