To develop, manufacture and test in Europe an Engineering Model prototype of a Xe Micro-pressure regulator.

 

The overall activity has been approved in the Strategic Initiative Work Plan (ref. ESA/IPC(2013)118,rev.2) which covers the Portuguese participation in the project. The present GSTP activity covers the involvement of a European company with expertise and heritage in propulsion components.

 

 

The state-of-the-art in Xenon feeding systems, specifically pressure control devices, which reduce the gas pressure from storage level, usually upwards of 100bar, to the pressures acceptable by the thrusters? XFC (i.e. circa 2 bar) is the Bang-bang pressure regulation unit (BPRU); such an equipment was, as an example, used in the Smart-1 mission. The BPRU allows extra safety, never allowing contact between the high and low pressure stages.

 

This type of equipment weighs several Kg and its discrete operation introduces noise in the spacecraft that in some cases (i.e. whenever high aiming accuracy or high instrumentation resolution are required) the BPRU will not allow for a smooth enough operation.

 

The activity aims at developing a 8mm thread pressure regulator. The range of operating pressures can be tailored to be that of a simple first stage pressure regulator which, on top of this has a very small size (e.g. fits into an M8 screw). The advantage of having the regulator based on the 8mm size pressure regulator technology is that the orifices are so small (between 10-100?m in diameter) and there is such an overlap of laminar layers that in practice a complete connection decoupling, between inlet pressure and exhaust flux, exists, allowing this pressure decrease to be totally independent from what is occurring further on.

 

There is the further advantage of mass savings and cost decreasing, as it should be less expensive to produce a mechanical pressure regulator weighting less than a hundred grams as compared with an electronically actuated BPRU of several Kg.

 

The proposed plan of work includes:

 

Design and preparatory work:

• Considerations on Xe Feeding Specifications for Hall Effect Thrusters.

• System Design of Acceptable First Stage (150bar to 2 bar) Regulator.

• Test plan elaboration for reliable operation demonstration and Qualification requirements according to ECSS.

 

Manufacturing:

• Manufacture of Engineering Model Prototypes (EMP?s).

 

Testing:

• Testing of EMP?s to achieve pre-qualification and TRL5 status.

• Roadmap for Qualification and achieving TRL6.