Research & Development

Micro Bi-Propellant Thruster

The trend to smaller satellite as well as the need for fine positioning of large satellites requires the development of propulsion systems which can support those new and challenging mission demands. The combination of requirements such as minimized system mass and volume, thrust in the low single digit Newton range, and highly accurate impulse bits can only be satisfied with a miniaturized chemical propulsion system.

Answering those needs of future space missions, AIT is developing a bipropellant thruster system in cooperation with the European Space Agency (ESA). The system under development is based on the usage of green propellants with hydrogen peroxide (87.5%) as oxidizer. Several "green" fuels such as ethanol and kerosene are investigated. Utilizing green propellants, i.e. propellant with none or negligible toxic or carcinogenic risk has several significant benefits. Beside of the obvious health benefits for everybody who handles a propulsion system operating with green propellants, it was also shown that the utilization of green propellants results in major financial savings both during development and operation.

The bipropellant thruster developed by AIT (see fig. 1) combines several unique features such as advanced monolithic catalysts, a swirler injector (see fig. 1, top left), regenerative cooling system (see fig. 1, top right) and a miniaturized combustion chamber (2.6 cm²). The decomposition chamber which provides the oxygen for the main combustion is based on the design as developed for the monopropellant thruster including the monolithic catalyst (Link: Monopropellant Thruster).

Fig. 1: AIT Bipropellant showing details of the injector and cooling system

Several laboratory models have been manufactured and tested in the chemical propulsion test facility of AIT (see fig. 2, 3). The successful tests have shown that indeed reliable ignition and combustion in such small volumes as present in the AIT bipropellant thruster are possible. This success makes the AIT bipropellant thruster to the smallest system of this kind which operates on green propellant.

Fig. 2: Bipropellant thruster assembled in the test facility

Furthermore, analysis showed that the performance of the present system makes this system very compatible with existing systems (see table below). Development is ongoing and verification of the data shown in the table is expected to be available in the near future.

AIT Micro Bi-Propellant Thruster

Thrust	1.7 -1.9 N
Thruster mass-Fuel-Oxidizer-Power	290 – 330 s
Specific Impulse (vacuum)	<100 g

Due to the successful test, a parallel development of an ignition system was initiated which is based on the bipropellant thruster technology (green propellants, advanced monolithic catalysts).
A first system study of such an ignition system is shown in fig. 3

Fig. 3: AIT system study of an ignition system for large scale chemical propulsion systems

Recent Publications:

• Scharlemann, C., Schiebl, M., Marhold, K., Tajmar, M., Miotti, P., Guraya, C., Seco, F., Kappenstein, C., Batonneau, Y., Brahmi, R., and Lang, M., "Test of a Turbo-Pump Fed Miniature Rocket Engine", AIAA Joint Propulsion Conference, AIAA-2006-4551, 2006
  
  
• Brahmi, R., Batonneau, Y., Kappenstein, C., Miotti, P., Tajmar, M., Scharlemann, C., and Lang, M., "Ceramic Catalysts for the Decomposition of H2O2. Influence of the Wash-Coat Procedure and the Active Phase", 8th International Hydrogen Peroxide Propulsion Conference, Purdue University, 18-21 Sept, 2005
  
  
• Scharlemann, C., Marhold, K., Tajmar, M., Miotti, P., Guraya, C., Seco, F., Soldati, A., Campolo, M., Perennes, F., Marmirolo, B., Brahmi, R., Kappenstein, C., and Lang, M., "Turbo-Pump Fed Miniature Rocket Engine", AIAA Joint Propulsion Conference, AIAA-2005-3654, 2005