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iFACT - Iodine Fed Advanced Cusp field Thruster

Periodic Reporting for period 1 - iFACT (iFACT - Iodine Fed Advanced Cusp field Thruster)

Reporting period: 2020-01-01 to 2020-06-30

Since several years, the industrialisation of the satellite market has accelerated. In particular, the market for telecom satellites has changed significantly, because of several new players and numerous plans for satellite constellations, such as OneWeb or Starlink. In addition, also the market for Earth observation satellites is in motion, due to the fact that the new market actors are not only focusing on telecommunication services, but also target earth observation missions.
In parallel to this development, electric propulsion, with its high mass efficiency, became an enabler to improve the cost efficiency of satellites, especially with respect to launch costs, because it allows the launch of more satellites per launch vehicle instead of one. So far, the savings have been potentially eaten up by the additional costs of the electric propulsion subsystem, which are mainly influenced by the complexity of the required electronics (PPU) and the high cost of the xenon propellant.
In order to increase competitiveness and to disrupt the electric propulsion market, we are proposing the development of the iodine Fed Advanced Cusp field Thruster (iFACT) subsystem within this programme. The programme is focusing on:
• Iodine as disruptive propellant for electric thruster,
• maturation of the Advanced Cusp Field Thruster (ACFT) as disruptive thruster principle, in three different power classes,
• calcium aluminate (C12A7) as disruptive, low-work function emitter material for cathodes,
• significant reduction and simplification of the PPU required.
Iodine as propellant can lead to a significant simplification of the propellant feeding subsystem architecture, which enables a significant cost reduction. It will further allow decreasing the mass of the feeding subsystem, because of its high storage density (three times higher than xenon).

The project aims to increase the knowledge on the compatibility of the iodine propellant with test facilities and diagnostics, including optimised tools, equipment and test procedures for the new propellant. In particular, one objective is to design and validate an independent testing infrastructure allowing long firing sequences with special emphasis on the safety procedures and measures to protect the environment.
The information gathered in the project, and in particular the results coming from the facilities characterisation, will be essential for future European industrial programmes on this type of technology.
A thruster which already runs perfectly on iodine is the Advanced Cusp Field Thruster (ACFT).

So far, all ACFTs tested have been operated with thermionic cathodes as neutraliser, this was in particular possible because of the comparably low input power (< 300 W) used. However, thermionic neutralisation requires a high amount of heating power with state of the art materials such as Lanthanum hexaboride (LaB6). To further improve the subsystem efficiency, a material with lower work function is required; a promising alternative is calcium aluminate (C12A7). It offers:
• a theoretical very low work function of 0.6 eV,
• it should be insensitive for poisoning with iodine.

In addition, for higher input power thrusters such as the future 1000 W iFACT, a hollow cathode becomes necessary for neutralisation, due to the high emission currents required. In the scope of the programme, we develop a hollow cathode, which can be operated with iodine in order to ensure that “high power” thrusters can make use of iodine as propellant. We develop a C12A7 as emitter material for the hollow cathodes, as well.
The first 6 month of the iodine Fed Advanced Cusp Field Thruster project has been used to kick off the development programme (kick off was performed a 14th of January 2020 in Friedrichshafen) to enable an adequate working and collaboration environment, including frequent meetings and to simply start the technical work as planned. Main achievements are:
• Establishment of a project visual identity,
• Launch of the iFACT website (www.epic-ifact.eu)
• Creation of an iFACT leaflet and other dissemination material and channels such as Twitter,
• Delivery of 9 deliveries,
• Successful performed SRR,
• Availability of an marked analysis and business plan,
• Several literature reviews.
In the recent period, the project has focused on creating a sufficient development environment and to kick off the activities required in order to enable the impacts promised in the programme’s proposal. A market analysis that has been performed within WP 3 that confirmed the assumptions made during the proposal phase.