The project addressed the markets that may be disrupted by the HiperLoc technology being available and the system requirements for a suitable HiperLoc configuration. Fundamental proof of concept tests were also been carried out to verify the approach proposed in the three subsystems: Colloid Thrust Head subsystem (CTH), Propellant Storage and Feed subsystem (PSFS) and the Power Processing subsystem (PPU).
From the analysis performed, the possible missions can be divided in 3 broad categories of requirements:
1. Nano/Microsatellite market:
This rapidly growing market represents one of the main users of a low cost EP system. Particularly these applications will require low level of thrust, and accept a low specific impulse, prioritizing extremely low cost and compactness over performance.
2. Small satellites mega-constellations:
This market is shifting the paradigm of the use of space with unprecedented volumes of production, that require easy to manufacture and cheap systems. These applications will have requirements somewhat similar to the nanosatellites’ market, prioritizing cost over performance (no need for low noise or high thrust resolution/throttling). But the required thrust will be in the tens of mN range and the Isp will probably be higher to save on the propellant mass consumed.
3. Science Missions:
Finally, science missions encompass both flagship missions like LISA and LEO science missions like NGGM. While the requirement will be clearly slightly different between the systems, the emphasis will be on performance. The required activities of formation flying and/or precise pointing will require sub-mN thrusts, with very high thrust resolutions (~0.5 μN) and the ability to continually throttle the thrust.
Of these the dominant market in the near future for the ECEPS will be the constellations and mega-constellations of CubeSats, especially in the 3U format. Therefore, this was selected as the baseline for the HiperLoc development and the requirements were derived accordingly.
Broadly, the ECEPS is required to be able to provide the required propulsion functionality for a 3U CubeSat platform to perform:
• Constellation deployment
• Station keeping in LEO for 5 years
• Deorbiting at EOL
Critical component testing was undertaken for each of the principal subsystems that comprise the ECEPS, namely: CTH, PSFS and the PPU. These tests allowed for detailed design to take place for each of the subsystems and a Bread Board Model (BBM) for the entire propulsion system was then manufactured to this design. This BBM can be seen in figure 1.
The results of the BBM tests have been used to identify modifications required to the system in order to take forward a further development of the system. These lessons learnt have been then included in a development plan. The development plan has identified a target opportunity for In-orbit Demonstration of the technology within the next two years.
