Periodic Reporting for period 2 - HIPATIA (HelIcon PlasmA Thruster for In-space Applications)
Reporting period: 2021-04-01 to 2022-12-31
In Space missions, the utilisation of Electric propulsion (EP) introduces important savings in terms of propellant consumption when compared to chemical thrusters. To date, electrostatic thrusters have been the preferred solution when introducing EP in different satellites platforms. They offer high design maturity and reliability but still present challenges regarding implementation impact and costs.
The Helicon Plasma Thruster (HPT, Figure 1) is a radiofrequency EP thruster that prospectively can offer a good level of performance while eliminating many of the design and manufacturability issues - electrodes, high voltage electronics, and complex fabrication - which have afflicted EP systems to date.
With this in mind, HIPATIA has focused on the development and evolution of the HPT and the technologies associated to it (fluidics and electronics), completing in this way the development and characterisation of a complete EP system for spacecrafts.
The Helicon Plasma Thruster (HPT, Figure 1) is a radiofrequency EP thruster that prospectively can offer a good level of performance while eliminating many of the design and manufacturability issues - electrodes, high voltage electronics, and complex fabrication - which have afflicted EP systems to date.
With this in mind, HIPATIA has focused on the development and evolution of the HPT and the technologies associated to it (fluidics and electronics), completing in this way the development and characterisation of a complete EP system for spacecrafts.
The HIPATIA project’s long-term goal is to develop an in-Space propulsion system based on the HPT concept. The project has advanced in the verification of the function and performances of a complete EP system based on the HPT. In this context, the HIPATIA consortium (SENER, UC3M, AIRBUS, CNRS and AST) has worked on four different fronts:
1) The identification of the potential target market, setting requirements for the system and the technology units developed within HIPATIA. This action has been complemented validating and verifying the requirements fulfilment in different milestones during the project execution.
2) In order to satisfy the requirements established for that market, the development of the main units constituting the propulsion system: Thruster Unit (TU, Figure 2 and Figure 3), Propellant Flow Control Unit (PFCU, Figure 4 and Figure 5), and Radiofrecuency Generation and Power Unit (RFGPU, Figure 6 and Figure 7);
3) The test of these units’ research and evolution models as well as the verification of the integrated system functionality and performances at different development stages (Figure 8, Table 1 and Table 2);
4) The understanding of the helicon plasma physics to help simulating, analysing and improving the system performances. This includes activities in researching alternative thruster configurations, alternative propellants and developing simulation codes.
The activities related to the aforementioned tasks have been developed following parallel paths that came together at different key points of the project’s development. During such milestones, the advances and obtained results were reviewed, assessed and cross-fed among the parallel paths, establishing the way forward for the next phases of the project. The results of the different investigation lines have been published in peer reviewed papers, conferences and workshops, and made available in the HIPATIA project’s webpage (www.hipatia.uc3m.es).
Overall, the project has conducted research and development activities that firstly led to the assembly, integration and test of Engineering Models of the TU, the RFGPU and the PFCU. The functional chain test, including the three units working together for the first time was successfully run in 2021. Engineering and Qualifications models were developed afterwards, considering the results of the first coupling test campaign, and tested together in 2022, achieving TRL5 for the HIPATIA system at the end of the project.
1) The identification of the potential target market, setting requirements for the system and the technology units developed within HIPATIA. This action has been complemented validating and verifying the requirements fulfilment in different milestones during the project execution.
2) In order to satisfy the requirements established for that market, the development of the main units constituting the propulsion system: Thruster Unit (TU, Figure 2 and Figure 3), Propellant Flow Control Unit (PFCU, Figure 4 and Figure 5), and Radiofrecuency Generation and Power Unit (RFGPU, Figure 6 and Figure 7);
3) The test of these units’ research and evolution models as well as the verification of the integrated system functionality and performances at different development stages (Figure 8, Table 1 and Table 2);
4) The understanding of the helicon plasma physics to help simulating, analysing and improving the system performances. This includes activities in researching alternative thruster configurations, alternative propellants and developing simulation codes.
The activities related to the aforementioned tasks have been developed following parallel paths that came together at different key points of the project’s development. During such milestones, the advances and obtained results were reviewed, assessed and cross-fed among the parallel paths, establishing the way forward for the next phases of the project. The results of the different investigation lines have been published in peer reviewed papers, conferences and workshops, and made available in the HIPATIA project’s webpage (www.hipatia.uc3m.es).
Overall, the project has conducted research and development activities that firstly led to the assembly, integration and test of Engineering Models of the TU, the RFGPU and the PFCU. The functional chain test, including the three units working together for the first time was successfully run in 2021. Engineering and Qualifications models were developed afterwards, considering the results of the first coupling test campaign, and tested together in 2022, achieving TRL5 for the HIPATIA system at the end of the project.
The final phase of HIPATIA, included the assessment of the project outcomes, including the evaluation of the Technology Readiness Levels (TRLs) following the ESA TRL Handbook as a reference. In this way, Figure 9 and Table 3 show the evolution in TRL of the different units to be developed in HIPATIA, plus the HIPATIA System itself along the whole project.
The most significant advances in this regard have been achieved at System level, its first integration being already achieved in early 2021, obtaining a TRL4-5, and followed-up by the second coupling test campaign integrating the TU and PFCU EQMs and the RFGPU EM, achieving TRL5.
For the RFGPU and PFCU the progress has also being important. In the case of the RFGPU, the assembled EM is considered TRL5, but it already implements functionalities that could be considered TRL6. For the PFCU, the EQM certified TRL6. Both units are ready for a direct transition towards Qualification Models in future development phases.
The TU EM was assembled and operated already in 2020 achieving TRL5. However, problems in its operation were detected and re-design was necessary. The progress towards the EQM solved some of these issues, but not the ones related to the poor thrust performances of the device, as depicted in Table 2.
A representative of a fly unit EQM was integrated and successfully operated in the required environment (TRL6), but this is a thruster that does not fulfil the necessary requirements to perform adequately for reference missions. Therefore, the advances in the TU development have not been as expected. Before the end of the project, a new design was proposed, implementing changes that will prospectively lead to improving thrust performances. There has not been time to assembly and test this model in the frame of HIPATIA. SENER and UC3M will continue working on it and expect to have results from testing it during the first semester 2023.
Despite the current low performances, given the relatively simple and robust design of the HPT technology (no grids, neither neutralisers), HIPATIA still has the potential for providing a cost-effective solution for large constellation of small satellites (<500 kg, <750W of power for EP) to perform in-orbit insertion, station-keeping and End of Life disposal. In addition to this, air breathing Very Low Earth Orbit (VLEOs) satellites could make use of HIPATIA, since the HPT technology provides a cathodeless solution that can operate in the conditions of those orbits (electrostatic EP systems cannot operate in presence of the atomic oxygen present in those orbits).
Considering all this, the HIPATIA Partners will continue their research activities on EP beyond this project and apply the lessons learnt during it in future activities. For the HIPATIA system, all these activities will aim at enhancing the propulsive performances and try to do In-Orbit Demonstration (IOD) in the coming years.
The most significant advances in this regard have been achieved at System level, its first integration being already achieved in early 2021, obtaining a TRL4-5, and followed-up by the second coupling test campaign integrating the TU and PFCU EQMs and the RFGPU EM, achieving TRL5.
For the RFGPU and PFCU the progress has also being important. In the case of the RFGPU, the assembled EM is considered TRL5, but it already implements functionalities that could be considered TRL6. For the PFCU, the EQM certified TRL6. Both units are ready for a direct transition towards Qualification Models in future development phases.
The TU EM was assembled and operated already in 2020 achieving TRL5. However, problems in its operation were detected and re-design was necessary. The progress towards the EQM solved some of these issues, but not the ones related to the poor thrust performances of the device, as depicted in Table 2.
A representative of a fly unit EQM was integrated and successfully operated in the required environment (TRL6), but this is a thruster that does not fulfil the necessary requirements to perform adequately for reference missions. Therefore, the advances in the TU development have not been as expected. Before the end of the project, a new design was proposed, implementing changes that will prospectively lead to improving thrust performances. There has not been time to assembly and test this model in the frame of HIPATIA. SENER and UC3M will continue working on it and expect to have results from testing it during the first semester 2023.
Despite the current low performances, given the relatively simple and robust design of the HPT technology (no grids, neither neutralisers), HIPATIA still has the potential for providing a cost-effective solution for large constellation of small satellites (<500 kg, <750W of power for EP) to perform in-orbit insertion, station-keeping and End of Life disposal. In addition to this, air breathing Very Low Earth Orbit (VLEOs) satellites could make use of HIPATIA, since the HPT technology provides a cathodeless solution that can operate in the conditions of those orbits (electrostatic EP systems cannot operate in presence of the atomic oxygen present in those orbits).
Considering all this, the HIPATIA Partners will continue their research activities on EP beyond this project and apply the lessons learnt during it in future activities. For the HIPATIA system, all these activities will aim at enhancing the propulsive performances and try to do In-Orbit Demonstration (IOD) in the coming years.