Propulsion research in the Netherlands centers around solid propellant as a source for both hot and cold gas, as well as structure development and testing for rocket engine frames and interstages.
Companies in the Netherlands have a long tradition of collaboration on the research and development of rocket propulsion begun by TNO in the 60’s. In more recent years, igniter systems have been developed by Dutch company Aerospace Propulsion Products (APP), the current European prime for such systems. The pyrogen type igniter finds its application in solid rocket motors, but also can be applied to liquid rocket engines. APP and TNO also developed igniters for the Vulcain II engine of the Ariane 5 launcher, and are now developing the igniters for the three solid rocket motors of the VEGA launcher. The development of the ignition system for the Vinci engine, with a unique restart capability suitable for upper rocket stages, is also underway.
The experience gained with igniters is now further used to develop small thrusters for attitude control of future launchers. With the advent of micro technology this research created a spring-board into the field of micro propulsion, where TNO, ISIS, and Dutch universities are trying to miniaturise the propulsion system to a minimum size. The goal is to provide propulsion systems for Cubesats and other small satellites.
TNO's Solid Propellant Cool Gas Generator, to be provided for the industrial market by Bradford Engineering, is a unique development that produces pure gas through decomposition of a solid material while the gasses leave the gas generator at ambient temperature. The gas generators have a high storage efficiency and can be sized from very small to large, covering application areas from small nanosatellites to large inflatable structures like airbag landing systems for planetary exploration. Bradford Engineering has also designed the proportional Xenon Feed Assembly that will guide xenon propellant down from the tank pressure to supply the main, cathode and neutraliser lines of GOCE’s Ion Thruster Assembly.
A core set of Dutch companies ensures the reliability of European launcher systems’ engine frames and interstages. Dutch Space is responsible for the design of launch vehicle structures for both the Ariane 5 and Vega launcher series. Dutch Space also has a history in providing engine frames and interstages for Ariane 1 through 4. The manufacture of these launcher structures is provided by Stork Aerospace and Dutch Space has brough TNO in to perform tests for both of ESA's Ariane 5 and Vega rocket engine frame and interstages. During the Ariane 5 failure test an impressive six-metre high structure exerted forces on the engine frame until the point was reached that the interstage actually collapsed. The forces exerted during flight will be far lower than those that were required for the collapse test. Designed by Dutch Space, built by Stork and tested by TNO, the Ariane 5 engine frame is ready for launch.