ABOUT RAPTOR VACUUM
The Raptor Vacuum (RVac) is the vacuum-optimized variant of the Raptor engine, featuring a large regeneratively-cooled nozzle extension for maximum performance in space. It powers the upper stage of Starship, with six RVac engines providing the thrust needed for orbital insertion and deep-space missions. The extended nozzle delivers significantly higher specific impulse than the sea-level Raptor.
Image: SpaceX
PERFORMANCE
| Thrust (Sea Level) | N/A (vacuum only) kN |
| Thrust (Vacuum) | 2,560 kN (575,000 lbf) kN |
| ISP (Sea Level) | N/A s |
| ISP (Vacuum) | 380 s s |
| Chamber Pressure | 30 MPa (4,351 psi) bar |
| Mass | 1 kg |
| Thrust-to-Weight | 153 |
| Throttle Range | 40–100% |
| Restart Capable | Yes (multiple) |
THRUST CONVERSIONS (VACUUM)
| Kilonewtons | 2.0 kN |
| Pounds-force | 450 lbf |
ENGINE CYCLE
Full-Flow Staged Combustion
The most advanced cycle: both fuel-rich and oxidizer-rich preburners drive separate turbopumps, and all exhaust flows into the main chamber. Maximizes performance and enables extreme chamber pressures. Only the SpaceX Raptor has flown with this cycle.
PROPULSION
| Propellant | Liquid Methane (CH₄) |
| Oxidizer | LOX |
| Engine Cycle | Full-Flow Staged Combustion |
| Mixture Ratio | 3.6:1 |
| Flow Rate | ~660 kg/s kg/s |
PHYSICAL
| Dimensions | 1.3 m diameter × 3.9 m length (with nozzle) |
| Combustion Chambers | 1 |
| Nozzle Expansion Ratio | 80:1:1 |
GENERAL
| Manufacturer | SpaceX |
| Country | United States |
| Status | Active |
| First Flight | April 22, 2026 |
VARIANTS (2)
- RVac
- RVac 2
VEHICLES USING RAPTOR VACUUM (1)
- Starship (upper stage)
ENGINE LINEAGE
Raptor Vacuum→Raptor 3 Vacuum
⚖ PROPELLANTS
🏢 MANUFACTURER
