ARTES AT Kr

System/ Network/ Protocols

Status

Ongoing
Status date

2025-01-15
Activity Code

4B.129

Objectives

The objective of the project is to mature the cathode of the PPS® low power thruster, namely the PPS®X00, for an optimized operation with Krypton as propellant, in view to offer a competitive efficient propulsion solution meeting the small satellite market demand, and of particular interest in the mega-constellation segment where the xenon availability is a key issue.

The following tasks are covered by the project activities:

First, the design and manufacture of a highly flexible device functionally and thermally representative of a hollow cathode, so-called BTC.
Then functional and thermal characterizations carried out with this hardware by varying the dimensions of the functional parts of the emitter’s housing, the material of the emissive element, and the propellant gases.
The third step consists in refining the cathode model developed by Safran by adjusting the modelling parameters after the measurements performed on the BTC
Finally, the design, manufacture and test a BBM "krypton hollow cathode" based on these results and complying with the specification.
The activities and logic defined at the beginning of the project benefit from synergies with the ARTES C&G PPS®X00 project.

Challenges

The world of space is constantly evolving. Depending on the health, economic and geopolitical context, the space market ecosystem is considerably affected and has to reinvent itself regularly. The compatibility of the propulsion system's operation with an available propellant gas, krypton, is an asset enabling us to offer an effective, low-cost solution for a low-power Hall-effect thruster, within a very tight time-to-market.

Benefits

The cathode developed in this project is dedicated to equip the PPS®X00 thruster. The main advantages of this product are its long life, excellent thrust to power ratio and performance perfectly meeting the market needs. Another competitive advantage is its ability to operate in a large operational range, both with xenon and krypton, meeting a wide variety of missions and satellite platforms.

The optimized design of the cathode of this thruster is made possible by more than 40 years of experience and heritage to offer a stable and high-performance Hall thruster. In addition, its simplified design and assembly, as well as the maturity of the Safran’ supply chain and production capacities, are in line with the expectations of target cost and mass production, corresponding to the needs of the low earth orbit constellation market and the deployment of new space service markets by the middle/end of the decade.

Features

The driving force of the PPS®X00 cathode technology lies in the approach adopted throughout the development process, as it takes into account both the evolving and versatile demands of the market and the product's ability to be industrialized.
Indeed, in few months the satellite market may experience a profound change.

The small satellite segment is particularly characterized by numerous and varied platforms, many of them with growth potential (in terms of available on-board power), and, within this market, the needs also differ from one spacecraft/customer to another. Thus, the more throttling capability, the more accessible market.

The panel of suppliers for Safran's electric thruster products is mature and almost entirely European, which ensures both the robustness of components, including the applied processes, and their availability. This, combined with the Safran group's strong production capabilities, places this thruster at the forefront of high-performance, competitive and reliable products for which high production volumes are required.

System Architecture

A Hall thruster is composed of an anode assembly and a cathode assembly. To create the thrust a magnetic field is generated in a dielectric chamber to achieve the Hall effect required to ionise the gas, confine the plasma and accelerate the ions under an electrical potential. Electrons are supplied to the anode block by the external cathode to initiate and maintain the discharge. These assemblies consist mainly of an anode/gas distributor, a discharge chamber, a magnetic system, a hollow cathode, gas and power supply lines and mechanical interfaces.

The basis of the project is to generate an optimal design in terms of cost and performance.

The PPS®X00 cathode architecture and assembly processes simplifications compared to legacy designs enable to reduce drastically the manufacturing cycle.

Plan

The major phases of the project are:

Design and manufacture a highly flexible device functionally and thermally representative of a hollow cathode.
Perform functional and thermal characterizations of this device by varying: i/ the dimensions of the functional parts, ii/ the material of the emissive element, iii/ the propellant gases.
Refine the cathode model developed by Safran by adjusting the modelling parameters after the measurements performed on the device
Design, manufacture and test a BBM "krypton hollow cathode" based on these results and complying with the specification

Current status

All the elements to pronounce a TRL6 maturity of the PPS®X00 cathode operating with krypton are available: necessary justifications, mitigation of risks associated with critical technologies, compliance with technical and commercial requirements, and industrial conditions such as the whole manufacturing chain consolidation.

The future development phase mainly consists in the assessment of the residual risks to consolidate the flight target definition through lifetime tests with Krypton, additional analyses and tests at component level. These activities are necessary inputs for the qualification phase, and entry into service in 2025.