To maturate a pre-developed thruster design and to confirm its suitability prior to a potential qualification for the VEGA RACS system.

In order to pro-actively counter the risk of a non-availability of a 240N thruster for the VEGA RACS system, the development aimed to maturate and pre-develop a 240N thruster with advanced manufacturing methods and to confirm its suitability prior to a full development / qualification. 

During the actual GSTP contract [AD 2] a 240N class Hydrazine thruster was designed in a classical (DM1b) and in a cost optimized version (DM1a). The cost optimized version used additive manufacturing in order to speed up the development process, to lower the number of single piece parts and thus lower the development and manufacturing cost. 

The following critical elements of an additively printed thruster were successfully verified during this program: 

• A first critical element of the thruster design is the heat barrier that has to be stiff on one hand to cover mechanical loads but needs to have a low cross section to limit thermal flux to the injector. This heat barrier was optimized using additive manufacturing with the target not to have an additional support structure. The design was further optimized via structural analysis and finally a demonstrator was printed and tested during a vibration test that confirmed the structural analysis. 
• The second critical element is the hydraulic path where significantly different pressure loss coefficients compared to classical tubes have to be considered due to the printed feed tubes. Hydraulic tests were performed with the injector head.The tests confirmed the initial assumptions of pressure loss coefficients for printed tubes that were gained in [RD 2]