HiETA Technologies progresses Qualification of Super High-Temperature AM Resistojet

Industry: Spacecraft Propulsion

HiETA Technologies, through the Catapult network and funded by the UK Space Agency, is partnering a consortium led by the University of Southampton and including H.C. Starck Solutions, Satellite Applications Catapult and Surrey Satellite Technology Ltd in a collaborative project to deliver an innovative new resistojet propulsion system named STAR (Super high Temperature Additively manufactured Resistojets).  

HiETA has been pushing the boundaries of Additive Manufacturing (AM) by developing world-class, novel thermal management systems for a variety of markets. AM has unlocked new design thinking for satellite propulsion by enabling engineers to build fine structures and complex 3D geometries that severely challenge traditional techniques. The STAR programme focusses on the next generation of Monolithic Resistive Heaters designed by the University of Southampton and consists of nested and interconnected heating elements [1,2]. 

A gaseous propellant flows through the Monolithic Resistive Heater’s convoluted metal path that is directly heated by electricity from the satellite bus. This increases the propellant temperature and thus the thrust efficiency of the system, pushing resistojet performance beyond the present state of the art.  For this to be realised, HiETA is developing bespoke AM machine parameters using a Renishaw RenAM 500E for high-temperature materials supplied by H.C. Starck Solutions.

The University of Southampton is conducting qualification tests on components produced by HiETA Technologies. These include life, performance, thermal, vibration, shock, leak and cleanliness tests. The tests will ensure that the Monolithic Resistive Heater heat exchanger meets the lifetime requirements of the selected missions, and will help to maximise the STAR thruster’s electrothermal performance through direct heating of the propellant.

In parallel, HiETA will ensure that its designs and processes are scalable for serial STAR thruster production, by making the build setup more efficient, and by streamlining post-processing techniques to ensure competitive unit costs. 

HiETA looks forward to realising the STAR component and applying it to alternative propulsion products, something achievable only through Additive Manufacturing. 

Radiograph of the additively manufactured resistojet STAR prototype
Radiograph of the additively manufactured STAR prototype [2].


[1] F. Romei, A.N. Grubišić, D. Gibbon, Manufacturing of a High-Temperature Resistojet Heat Exchanger by Selective Laser Melting, Acta Astronaut. 138 (2017) 356–368. doi:10.1016/j.actaastro.2017.05.020.

[2] F. Romei, A.N. Grubišić, Validation of an Additively Manufactured Resistojet Through Experimental and Computational Analysis, Acta Astronaut. 167 (2020) 14-22.