11-12 March 2025

London ExCeL

IENAI’s ATHENA™ thrusters pass first technical milestone as part of ESA maturation program

26th January 2024

IENAI’s propulsion technology has just passed its first technical milestone in a “Preliminary Design Review”, as part of the technology maturation activities supported by the European Space Agency. The achievement paves the way for next technical milestones and a first commercial thruster by the end of 2024.

IENAI SPACE and the European Space Agency jointly announced the successful closing of the “Preliminary Design Review (PDR)” for IENAI’s ATHENA™ (Adaptable THruster based on Electrospray powered by NAnotechnology) propulsion system; specifically, the PDR focused on the NANO version of ATHENA™, intended for cubesats 3U and above, and up to 50kg microsats. The news comes just over half a year after kicking-off the technology maturation activities in the framework of ESA’s GSTP program.

IENAI has been developing ATHENA™ since late 2020, having self-funded the early technology development activities to bring the novel ‘electrospray’ technology to European and global markets. Electrospray thrusters are a disruptive technology for the “low” (100-1000W) and “very low” (<100W) electric propulsion market, due to the high efficiency, independent of power class, high thrust-to-power ratio and their unparalleled compactness, which translate to low fuel consumption in orbit and fast maneuvering times. ATHENA™ also adds an additional layer of innovation in the form of a ‘software-defined’ approach to customization, through IENAI’s 360™ mission analysis tool, which enables clients to integrate propulsion systems tailored to their specific space mobility needs.

Furthermore, ATHENA™ uses ‘green’ ionic liquid propellants, instead of the noble gasses typically used in electric propulsion: Xenon, Krypton or Argon. The first two provide good performances at the cost of exorbitant prices and difficult to access supply chains (typically tied to Russia and China and other non-aligned geostrategic actors), while Argon is more affordable has suboptimal performances. Ionic liquids, on the other hand, are unique in that they offer a no-compromise solution for performance, cost and availability. ATHENA’s fuel also compares positively to the recently introduced Iodine propellants, which can have corrosive effects on the spacecraft and its components.


The technical milestones and a European “first”

The “Preliminary Design Review” (PDR) meeting took place at IENAI’s HQ in Madrid (Spain) during the 6th and 7th of November. IENAI’s engineering team, led by IENAI’s Project Manager Alberto Alonso, presented to ESA delegates from the Electric Propulsion Lab (EPL) their advances in hardware development for the main three subsystems of the thruster: the Thrusting Unit, the Propellant Management Unit and the Power and Control Unit, which are all built in-house by the company.

The PDR discussions focused on a major technological milestone: ATHENA™ reached 400h of continuous operation in vacuum conditions, doubling the recommended target set by the ESA micropulsion handbook for the current TRL. This achievement constitutes a European ‘first’ for an ‘electrospray’ thruster and provides confidence that the team will reach the minimum commercial target of 1000h of operation in the coming months, which will allow ATHENA™ to deliver total impulses of the order of ‘kilo’-Newton-seconds.

The activity was also supported by established Spanish space companies such as Deimos Space, bringing their expertise on Product Assurance and Assembly, Integration, Testing and Verification of complex space systems, and engineering consultancy Madrid Space, which provided thermal and structural analyses, as well as Radiation Analysis Services Ltd (RASL), a UK company specializing in space radiation environment consultancy.

Dr. Mick Wijnen, CTO of IENAI SPACE commented on the accomplishment: “Our partners’ and our team’s hard work and dedication have paid off spectacularly and ESA’s support has been invaluable as independent verification of the technology’s capabilities. Having passed PDR we are now just ‘months’ away from a fully operational and qualified thruster.”

The company also took the chance to provide ESA with engineering analyses of the thruster for thermal, structural and radiation environments expected during the launch and operation of ATHENA™, which are based on a wide envelope of potential commercial missions for smallsats (3U-27U & up to 50kg microsats) up to high-LEO, and will serve as a basis for the qualification stage of the thruster during 2024. IENAI also delivered the design for the Engineering Model of the thruster which the company will focus on for the upcoming technology development tasks; the mechanical, electrical and data interfaces have been reworked to ensure compatibility with a broad range of commercial satellite buses.

Eduard Bosch, one of the technical officers at ESA’s Electric Propulsion Laboratory, responsible for supervising the project activities commented: “My personal opinion about the datapack and work performed up to date by IENAI cannot be better. The team worked over the clock to finalize the demonstration of the limited endurance test before the colocation meeting, which was the only missing element for a successful verification of a preliminary design, and has achieved it successfully. I can only congratulate the team for this achievement and expect the same level of quality in the workmanship for the future reviews.”

Roadmap toward commercialization

The next technical milestones will be presented to ESA as part of the “Critical Design Review”, currently scheduled for the first half of 2024, which will then be followed by a ground qualification campaign for the thruster, including full lifetime verification. The company has already booked 2 flights for technology demonstration of ATHENA™ in orbit, which are scheduled for the end of 2024, leading up to the commercialization phase of the thruster.

Dr. Daniel Pérez Grande, CEO & Co-founder of IENAI SPACE commented on the momentum generated by the latest technical achievements: “Everyone knows that ‘space is hard’, but we like to say that ‘propulsion is harder’. Developing a new technology, which we have built from scratch, has been no easy feat, but we are confident that our propulsion products will stand out in the market for their incredible performance and customization capabilities; and in fact we have already been approached by a number of interested parties in the industry”.

The company plans to release a comprehensive portfolio of electric propulsion solutions for small satellites in the coming years, starting with ATHENA™ NANO, a 0.5U system which is targeted at cubesats (3U-27U), with direct integration for most commercial cubesat buses, and small microsats up to 50kg, followed by a larger “MICRO” version and a smaller “PICO” thruster aimed at satellites under 3kg, including pico-satellites. IENAI SPACE is currently the only company worldwide focusing efforts on developing a commercially viable picosatellite thruster, a market which is currently unaddressed by all other propulsion providers. The breadth of solutions planned is enabled by the inherent scalability of electrospray technology, and the company’s innovative ‘building blocks’ approach.



IENAI SPACE is an in-space mobility company focusing on the next generation of small satellites. The company is building an end-to-end ecosystem of products to address the complete value chain regarding propulsion and mobility for spacecraft builders and operators, through cutting edge hardware, based on ‘Electrospray’ technology, and advanced software, addressing industry pain-points.

The company released their first commercial product in October of 2023: 360™, a Mission and Space mobility analysis tool, having successfully completed a closed BETA trial with more than 30 companies and institutions from the space industry.

IENAI SPACE is headquartered in Madrid, Spain, and has offices in Barcelona (Spain) and Uppsala (Sweden). They can be contacted at a info@ienai.space for more information on their product ecosystem and upcoming missions.


Dr. Daniel Pérez Grande, CEO and Co-Founder at IENAI SPACE, is all set to take the stage at Space-Comm Expo 2024 alongside 60+ world-class speakers! Click here to secure your free ticket to attend IENAI SPACE’s session.

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