The main propulsion engines of a spacecraft usually operate in two modes:
- Interlunar mode, providing high propellant economy for the extended burns during interlunar travel, serving both as propulsion and artificial gravity.
- RCS support mode, sacrificing efficiency to provide high thrust for in-ring operations.
| Name | Manufacturer | Price | Thrust | Mass | Exhaust Velocity | Propellant Consumption | Power Consumption | Thermal Consumption | Response Time | Operation Mode | Other |
|---|---|---|---|---|---|---|---|---|---|---|---|
| ND-PNTR engine | Nakamura Dynamics | 7,000 E$ | 1,500 kN | 450 kg | 8 km/s | 187.5 kg/s | 180 MW | 6 GW | 2.1 s | Pulsed thrust | Vectored thrust (90°) |
| RA-TNTRL-K37 engine | Rusatom-Antonoff | 15,000 E$ | 750 kN | 1,250 kg | 15 km/s | 50 kg/s | 100 MW | 5.6 GW | Pulsed thrust | ||
| ND-NTTR thruster | Nakamura Dynamics | 30,000 E$ | 3,500 kN | 650 kg | 7 km/s | 500 kg/s | 20 MW | 12.2 GW | Variable thrust | ||
| RA-MHFTR-K44 engine | Rusatom-Antonoff | 40,000 E$ | 1,500 kN | 1,650 kg | 18 km/s | 83.3 kg/s | 100 MW | 13.5 GW | Pulsed thrust | Gimbaled (9°) | |
| BWM-T535 | BWM | 120,000 E$ | 535 kN | 2,000 kg | 29 km/s | 18.4 kg/s | 0.04 MW | 8.2 GW | 0.9 s | Variable thrust | Integrated turbine |
| ERS-DFMHD-2205 | Electro Ride Systems | 175,000 E$ | 2,200 kN | 2,450 kg | 14 km/s | 157.1 kg/s | 120 MW | 15.4 GW | 0.6 s | Variable thrust | |
| MA-NMPD42 engine | Mitsudaya-Starbus | 300,000 E$ | 320 kN | 1,850 kg | 115 km/s | 2.8 kg/s | 150 MW | 18.4 GW | Variable thrust | ||
| Experimental NPMP engine | Elon Interstellar | 700,000 E$ | 1,100 kN | 2,750 kg | 45 km/s | 24.4 kg/s | 200 MW | 24.7 GW | Pulsed thrust | ||
| Z-Axial Pinch fusion torch | Elon Interstellar | 1,000,000 E$ | 800 kN | 3,000 kg | 1,250 km/s | 0.6 kg/s | Variable thrust | Gimbaled (30°), fusion drive with 30min burn time |
The Z-Axial Pinch Fusion Torch (ZAP Drive) works differently than the other engines. When firing, it requires 150 MJ of power to ignite but is self-sufficient once fusion has started. Extended capacitor arrays are recommended to prevent overdraw. Fusion fuel lasts for 30 minutes of thrust and can only be viewed using the EIME HUD.