US EPA

1529093 

Journal Article 

Design and performance characterization of a sub-Newton N2O monopropellant thruster 

Cai, G; Sun, Wei; Fang, Jie; Li, Mao; Cong, Yu; Yang, Zhe 

2012 

Yes 

Aerospace Science and Technology
ISSN: 1270-9638 

23 

1 

439-451 

10.1016/j.ast.2011.10.003 

WOS:000313380100045 

This paper describes the research at Beihang University for
developing a sub-Newton thruster based on catalytic decomposition of nitrous oxide (N2O) for fine
attitude control of small spacecrafts. The characteristics of the N2O self-pressurization feeding
process as well as the preheating process of a sub-Newton N2O thruster were studied. Experimental
and simulated results indicated that the tank pressure decreases during the N2O self-
pressurization process. The influence on the preheating process of the surface emissivity, the
preheating power, the thickness of combustor chamber and the insulation material, were compared.
N2O catalytic decomposition experiments were carried out to evaluate the reaction performance of
Iridium impregnated modified alumina catalyst, such as activation temperature and reaction
temperature. Successful activation and self-sustaining reaction were achieved at 523 K. It was
found that the integral structure of the reactor and the loading factor of the catalyst-bed can
influence the reaction effect. Based on further experiments looking for proper catalyst-bed, a
thruster with a 4310 mm x 25 mm catalyst-bed was designed and fabricated. The vacuum performance
of the thruster at different N2O flow rates was evaluated using a vacuum experimental system,
which consists of a vacuum chamber and a sub-Newton-thrust measuring stand. Static vacuum thrusts
ranging from around 140 mN to 970 mN were achieved with the flow rates altering from around 0.1
g/s to 0.6 g/s. The highest specific impulse reached 1640 N s/kg. (C) 2011 Elsevier Masson SAS.
All rights reserved. 

Nitrous oxide; Monopropellant; Micro-propulsion; Self-pressurization; Preheating