Most of the satellites currently operating in orbit are kept in position and manoeuvred using hydrazine, a fuel that has been standard in spacecraft propulsion since the 1960s. Hydrazine is effective. It is also acutely toxic, carcinogenic, highly flammable, and classified as a substance of very high concern under European chemical regulations.
Fuelling a satellite with hydrazine requires specialist facilities, hazardous materials handling, and the kind of operational complexity that adds weeks and cost to launch preparations.
Arkadia Space, a startup based at Castellón Airport in eastern Spain, has spent the past five years building a credible alternative, and this week it received the most significant institutional backing yet for that work: €14.5 million from the European Innovation Council Accelerator.
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The package, structured as a €2.5 million grant, €6 million in equity from the EIC Fund, and €6 million in private investment, makes Arkadia the first Spanish space company to access the EIC Accelerator, one of the European Union's most competitive deep-tech funding instruments.
Arkadia was selected from 923 applications, as one of 61 startups chosen in this round. The European Commission's backing carries weight beyond the money: it is an explicit institutional signal that Europe considers hydrogen peroxide propulsion a strategic technology worth developing domestically.
Arkadia's approach centres on a hypergolic bipropellant system combining high-concentration hydrogen peroxide with a proprietary green fuel. Hypergolic means the two propellants ignite spontaneously on contact, eliminating the ignition hardware that conventional engines require and improving reliability for precision manoeuvres, docking operations, and, eventually, lunar landings.
The company claims the system can reduce operational and refuelling costs by more than 60 per cent compared to conventional solutions, a figure driven partly by the far simpler ground handling that hydrogen peroxide allows relative to hydrazine.
The technology reached a meaningful milestone last year. Arkadia's DARK propulsion system, launched in March 2025 aboard a D-Orbit ION Satellite Carrier on SpaceX's Transporter-13 rideshare mission from Vandenberg Space Force Base, became the first hydrogen peroxide-based propulsion system to fly in orbit in Europe.
By June 2025, the company had confirmed successful in-orbit test firings, including both short pulses and longer steady-state burns, and reported that on-orbit performance matched ground test data. The launch also demonstrated a practical selling point: hydrogen peroxide can be fuelled at the launch site without the hazardous procedures hydrazine demands, cutting pre-launch costs and complexity for satellite operators.
Alongside DARK, Arkadia has developed ARIEL, a 250-newton monopropellant thruster designed for reaction control systems on launch vehicles and spacecraft, built under contract with ESA's Future Launchers Preparatory Programme.
ARIEL reached technology readiness level six within two years of the initial ESA contract signed in June 2023, and Arkadia has since secured a contract to supply reaction control thrusters for MaiaSpace, the reusable launch vehicle programme backed by ArianeGroup. Ismael Gutierrez, co-founder and CTO, leads the technical work.
The EIC funding will support commercialisation, further R&D, testing infrastructure expansion at Castellón Airport, and scaling of commercial operations.
Francho García, co-founder and CEO, said the backing arrives at the moment when the company has already demonstrated market fit: “We have demonstrated that our technology meets market requirements and that there is a real performance alternative to highly toxic fuels,” adding that the goal is commercial deployment as early as next year.
Arkadia describes itself as the only company in the world with propulsion systems at this level of development in hypergolic hydrogen peroxide technology, a claim that, if it holds, positions it as a sole-source supplier to European space programmes seeking to move away from hydrazine dependency before tightening EU chemical regulations make that transition compulsory.