Improving technology: reaction control thrusters
The ARTES programme assists in activities assuring an independent European satcom industry. At times, there are situations where technologies need to be improved or changed.
A current ARTES 3-4 activity is investigating a new design to a satellite’s reaction control thrusters (RCTs).
RCTs are used to control the attitude and the orbit of telecom satellites throughout their orbital life. The key performances of RCTs are driven by valves which control the propellant flow.
Designed by Astrium in Lampoldshausen, Germany, these thrusters are subject to constraints under the International Traffic In Arms Regulations or ITAR, which are American government regulations that control the export and import of defense-related articles and services on the United States Munitions List (USML). Some satellite-related components fall under this list.
When Thales Alenia Space (FR) wanted to design a version of its SpaceBus platform which would be free of any US export constraint, and therefore gain access to a wider range of launchers, an opportunity arose to design an RCT with valves independent of ITAR.
This would give a cheaper access to space to regional operators while maintaining a high performance telecom satellite.
Working in cooperation with Astrium – initially Les Mureaux and then transferred to Lampoldshausen – a new valve was designed that relied on titanium bellows. While independent of ITAR, titanium bellows have been known to be problematic. It was a solution, albeit not the most optimal one. The valves were finally qualified but extensive controls were needed on the product resulting in major costs. Was this the only solution?
ARTES and RCT valves
A new version of the Astrium valves were planned to be used on the ARTES8 Alphabus platform. This new design relied on bending tubes to replace the bellows. The bending tubes act as a spring to close the valve when not powered and help control the kinematics of the opening. The functional design is slightly more difficult, but ultimately the manufacturing of this component is a lot easier and reliable.
However the development of this new valve was not compatible with the Alphabus/Alphasat programme timeline and could not be finalised even though the need for this product still remained, for SpaceBus in particular.
An ARTES 3-4 activity was initiated to cover a last iteration on the new design of the valves, and qualify the complete thrusters for a wide range of telecommunication applications ARTES 3-4 has enabled the design, development and qualification of ITAR-free bending tube valves, which are now being used in fully European RCTs.
Four flight sets are currently being produced at a competitive price. The ITAR-free bending tube valves, of a European design, will be manufactured in Europe.
Last Update: 27 Sep 2011