ESA’s Tiny Pinhole Thruster is Ready for Production. 

Rocket propulsion technology has progressed leaps and bounds since the first weaponised rockets of the Chinese and Mongolian empires. They were nothing more than rocket powered arrows and spears but they set the foundations for our exploration of space. Liquid propellant, ion engines and solar sails have all hit the headlines as we strive for more efficient methods of travel but a team has taken the next leap with a palm sized thruster system that could boost future tiny space craft across the gulf of space.

Palm sized thrusters are quite different to the gargantuan rockets we are used to, for example the Saturn V rocket that took the Apollo astronauts to the Moon which stood 110m tall. The difference for the ATHENA thrusters is that they are designed for manoeuvring and propelling cubesats and small satellites once they are in space rather than propelling rockets from the surface of the Earth. 

The Apollo 10 Saturn V during rollout. Credit: NASA

The team led by Daniel Perez Grande, CEO and Co-Founder of IENAI Spain, have called their palm sized thruster ‘Athena’, not the most catchy title but neatly represents what it does- the Adaptable, THruster based on Electrospray powered NAnotechnology.  The technology has been developed for ESA and, following a successful design stage and, if all goes to plan, a prototype will be available by the end of 2024. 

The technology relies upon something known as an electrospray which has previously been used in mass spectrometry but has now found its way into space. Each thruster has seven emitter arrays that are etched onto silicon wafers and each houses 500 pinhole emitters.  Electrically charged particles from a conductive salt are sprayed out, propelled via an electrostatic field to produce the maximum amount of thrust which can be of the order of 20km per second. The concept is very similar to the ion propulsion systems already in use but on a much smaller scale. 

Like its ION and liquid propellant cousins the thruster is highly adjustable and can be reconfigured in flight. The thrusters are eco-friendly too since the propellant is a non-toxic liquid and require no pressurised storage tanks. The small size of the thrusters means they can be grouped together in any required configuration with a total of six required to fit the face of a typical 10cm cubesats and can be clustered together on satellites and probes of up to 50kg mass. The team are hoping they can develop the technology further to work on craft up to 300kg. 

Space technology is where possible, getting smaller and smaller like most other areas of technology. In order to achieve this though the propulsion systems also need to shrink and this is potentially a more challenging ask. ATEHNA looks to be a promising development but ESA and their partners are working on two other thruster systems based upon electrospray technology all of which, seem to be bringing promising results.