Device for thrust generation

The apparatus has two propellant charges (4), where each charge is provided with an igniter (8) and the igniter of one of the charges is initiated independent of the igniter of the other propellant charger. A retaining device for receiving incineration particles of the propellant chargers is arranged between a gas discharging nozzle (7) of a combustion chamber (3) and a gas releasing nozzle of a neighboring combustion chamber, where the retaining device is formed by steel wool (5) and/or a retaining grid (6). The propellant chargers are sequentially and independently activatable.