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CORDIS - Résultats de la recherche de l’UE

iFACT - Iodine Fed Advanced Cusp field Thruster

Periodic Reporting for period 3 - iFACT (iFACT - Iodine Fed Advanced Cusp field Thruster)

Période du rapport: 2021-01-01 au 2022-06-30

In recent years, the satellite market has grown rapidly, especially for telecom and Earth observation satellites. This is due to the entry of new players and the development of new satellite constellations, like OneWeb and Starlink. Electric propulsion technology has also become important in the industry because it improves the cost efficiency of satellites, particularly with respect to launch costs, by allowing more satellites to be launched per vehicle. However, the additional costs of electric propulsion subsystems, mainly from the complexity of the required electronics (PPU) and high cost of the gas propellants like xenon, which is a type of gas used to fuel electric propulsion systems, can offset these savings. The conflict in Ukraine has also led to an increase in the cost of xenon propellants.

To make electric propulsion more cost-effective and competitive, iFACT researchers proposed developing a new subsystem called the iodine Fed Advanced Cusp field Thruster (iFACT). This subsystem was developed in the frame of the project and relies on the use of iodine as a propellant, which simplifies the propellant feeding subsystem architecture and reduces its mass due to its high storage density. The project focused on the maturation of a new type of thruster called the Advanced Cusp Field Thruster (ACFT) that can run on iodine. To further improve the efficiency of the subsystem, a material with a lower work function was required, and calcium aluminate (C12A7) was found to be a promising alternative. Additionally, iFACT team tried to reduce the complexity of the required electronics (PPU) and make electric propulsion more efficient.

One of the objectives of the project was also to investigate the compatibility of iodine propellant with test facilities and diagnostics, and to design and validate a dedicated testing infrastructure with a special focus on safety procedures to protect the environment. This information and the entire project results will be crucial for future European industrial programs that involve this technology. Iodine is also being considered as a promising candidate for the IRIS^2 constellation, a satellite constellation project.

The Advanced Cusp Field Thruster (ACFT) is a type of thruster that works well with iodine as a propellant. However, scientists wanted to improve the efficiency of the thruster system, so they looked for a better material for the cathode. They found that calcium aluminate (C12A7) could be a promising alternative, because it has a very low work function of 2 eV in theory and it shouldn't be affected by the iodine. The iFACT program made it possible to use C12A7 in cathodes in the future, which could improve the efficiency of the thruster system even more. The program's success could lead to major advancements in satellite technology and pave the way for a more sustainable space industry.
iFACT was a successful project that involved 8 different European partners working together to achieve the goals of the programme. Airbus Germany was in charge of the project coordination and developing the EP subsystem breadboards. Airbus France provided detailed specifications to ensure that the hardware met real market needs. Work package 4 and work package 5 had the goal to develop and provide an iodine fed cathode required to operate the thrusters.

The University of Southampton in Great Britain developed a hollow cathode made of iodine-compatible parts that can easily switch out emitter material to study different materials and propellants. The Fraunhofer institute for ceramics (IKTS) performed a parametric optimization of Calcium-Aluminide (C12A7), a low work function material that could work well with iodine, to improve its function. Within iFACT, Aerospazio Tecnologie, Italy, has built an EP-test facility tailored for very long iodine testing. This Facility has been used to test the 300 W iFACT subsystem for more than 3000 h in total, providing the proof that long term iodine firing and therefore lifetime testing is possible. The Justus Liebig University tested various materials commonly used on satellites for their compatibility with iodine and found that all materials tested worked well.

The developed technologies of iFACT need to be tested in space to have the highest impact. An iodine-fed thruster has already been coupled with a CubeSat platform for testing. Last but not least, EASN-TIS ensured that the project and its achievements were communicated to the iFACT stakeholders and the general public throughout the project’s lifetime.
iFACT project developed and demonstrated key building blocks to promote the use of iodine as a propellant for electric propulsion. Three different iodine-fed thrusters were built and tested since 2020, including a successful coupling of a CubeSat sized thruster with an Endurosat CubeSat platform. The 300W Advanced Cusp Field Thruster (ACFT) subsystem was operated for more than 3000 hours in a vacuum facility developed within the program that is compatible with iodine.

The iFACT team developed a method to test different materials to see how well they work with iodine in space propulsion systems. This method allows for the selection of the best materials for each specific use-case. They also found that at low pressures, similar to those experienced in space, there is minimal damage to the materials used with iodine.

The iFACT team ran a test for 3000 hours on a thruster that used iodine as a propellant, which is the longest and most powerful test of its kind. The team found that using iodine did not have any negative effects on the satellite in space and that it could be used for all current applications. This breakthrough paves the way for Europe to lead the way in using iodine for space propulsion.