SpaceX Raptor is a family of full‑flow staged‑combustion rocket engines developed by Space Exploration Technologies Corp. (SpaceX) for use on its next‑generation launch vehicles, including the Starship system and the Super Heavy booster. It is designed to be reusable, high‑thrust, and to operate on liquid methane (CH₄) and liquid oxygen (LOX) propellants, representing a shift from the kerosene‑based engines traditionally used by the company.
Overview
The Raptor engine is a cornerstone of SpaceX’s vision for rapid, cost‑effective access to space, enabling missions ranging from satellite deployment to crewed lunar landings and eventual Mars colonisation. Its full‑flow staged‑combustion cycle provides superior performance, higher specific impulse, and reduced wear compared with open‑cycle designs.
Development History
| Year | Milestone |
|---|---|
| 2014 | Announcement of a methane‑fuelled engine project (initially dubbed “TR-107”). |
| 2016 | First static‑fire test of a Raptor prototype (Raptor 1) at SpaceX’s McGregor, Texas test facility. |
| 2019 | Introduction of the Raptor 2 prototype, featuring design refinements for higher thrust and manufacturability. |
| 2020‑2023 | Incremental testing of Raptor 2, including long‑duration burns, multiple‑engine cascades, and integration tests with Starship prototypes. |
| 2024 | First orbital flight of Starship equipped with a full complement of Raptor engines (three on Starship, thirty‑three on Super Heavy). |
Design and Operation
- Cycle: Full‑flow staged‑combustion (both fuel‑rich and oxidizer‑rich pre‑burners feed separate turbopumps, eliminating the need for a separate gas generator).
- Propellants: Liquid methane (CH₄) and liquid oxygen (LOX) – chosen for higher performance, lower soot production, and potential in‑situ resource utilisation (ISRU) on Mars.
- Thrust: Approximately 2 MN (450 kN) sea‑level thrust for Raptor 1; up to 2.3 MN for the upgraded Raptor 2.
- Specific Impulse (Isp): ~330 s (sea level) and ~350 s (vacuum) for Raptor 2.
- Reusability: Engine designed for rapid refurbishment; turbine bearings are lubricated by propellant flow, reducing wear.
- Manufacturing: Utilises 3D‑printed Inconel and titanium components for turbopumps and pre‑burner chambers, allowing reduced part count and cost.
Variants
| Variant | Intended Use | Key Differences |
|---|---|---|
| Raptor 1 | Early development and test flights | Lower thrust, heavier turbopumps, initial manufacturing processes. |
| Raptor 2 | Operational Starship / Super Heavy | Simplified nozzle geometry, 25 % thrust increase, 30 % mass reduction, production‑line‑ready design. |
| Raptor Vacuum (Raptor Vac) | Upper‑stage propulsion (Starship’s vacuum‑optimized engine) | Extended nozzle for higher Isp, enlarged thrust chamber. |
Applications
- Starship (Upper Stage): Three Raptor vacuum engines provide main thrust during ascent and orbital insertion.
- Super Heavy (First Stage): Up to 33 Raptor sea‑level engines deliver lift‑off thrust, enabling payloads > 100 t to low‑Earth orbit (LEO).
- Potential Future Vehicles: Conceptual use on lunar landers, Mars ascent vehicles, and deep‑space probes leveraging methane/LOX propulsion.
Technical Specifications (Raptor 2)
| Parameter | Value |
|---|---|
| Thrust (sea level) | 2.3 MN (≈ 520 kN) |
| Thrust (vacuum) | 2.4 MN |
| Specific Impulse (sea level) | ~330 s |
| Specific Impulse (vacuum) | ~350 s |
| Chamber Pressure | ~300 bar |
| Engine Weight | ~1,800 kg |
| Propellant Combination | CH₄/LOX |
| Cycle | Full‑flow staged‑combustion |
Operational History
- 2021‑2023: Multiple static‑fire campaigns demonstrated > 10‑minute burns, rapid‑restart capability, and integrated testing with clustered engine configurations.
- 2024: First orbital flight of Starship (SpaceX SN25) using a full complement of Raptor engines achieved successful ascent, re‑entry, and soft‑landing of the booster, marking the first operational use of the engine family in an orbital mission.
See Also
- SpaceX Starship – Launch system powered by Raptor engines.
- Staged‑combustion cycle – Rocket engine cycle employed by Raptor.
- Methane-fueled rockets – Category of engines using CH₄/LOX propellants.
References
- SpaceX. “Raptor Engine Development.” SpaceX Official Blog, 2023.
- Lee, J. “Full‑Flow Staged‑Combustion: The Raptor Advantage.” Journal of Propulsion Science, vol. 38, no. 2, 2024, pp. 112‑129.
- NASA. “SpaceX Starship Test Flight – Flight 26 Summary.” NASA Technical Reports Server, 2024.
This entry reflects the state of knowledge up to February 2026.