PEPEk-30 Rocket Engine

A PEroxide Propulsion Element
Design philosophy

A propulsion system is one of the most critical parts of a space vehicle. Hence, from the very beginning of the design phase, the focus has been on the design simplicity and user-friendliness. The PEPE engines are highly throttable and work with storable, green and dense propellant combinations. The injector’s wetted area is highly variable, which allows for deep throttling without O/F mixture ratio shift and/or combustion instability issues.

Key design parameters of the concept
  • Storable , non toxic , environmentally friendly propellants :
    –> H2O2 + Alcohol blended fuel
  • Hypergolic (i.e. spontaneous) ignition by means of a special (starting) hypergolic fuel mixture:
    –> No ignition system required, no solid catalyst required
    –> Restart ability
    –> Allows to use a stabilized technical “T” grade peroxide
  • Variable injector wetted area :
    –> Highly throttable (Thrust level lower limit only due to pump limitations and/or nozzle flow separation.)
    –> Gradual startup / shutdown sequences, low risk of a hard start
    –> An idle run possible (a “standby” mode)
  • Lower chamber temperature , moderate chamber pressure:
    –> Better reusability (longer lifespan)
  • Propellants supplied by means of electric pumps:
    –> Simple and reliable pumping system
    –> Low pressure propellant tanks for enhanced user friendliness and safety level
Nominal thrust at the sea level33kN
Thrust level range (% of the Nominal)15% - 115%
OxidizerH2O2 90% + stabilized
FuelHydrocarbon fuel
Nominal chamber pressure4.0 MPa
Average propellant density1250 kg/m3
ISP at the sea level* nozzle expansion ratio 6.5235 s
ISP in vacuum* nozzle expansion ratio 6.5260 s
ISP in vacuum* - vacuum version, nozzle expansion ratio 150307 s
*At nominal conditions; Frozen equilibrium at the throat; Expansion ratio 9.0; Nozzle efficiency 0.985; C* efficiency 0.95
Specifications Chamber and Nozzle
Chamber Pressure [bar]4040
Chamber peak temperature [K]27002700
Nozzle expansion ratio9.0150
Specific Impulse
Specific Impulse
sea level*
* Calculated; At nominal conditions; Frozen equilibrium at the throat; Nozzle efficiency 0.985; C* efficiency 0.95