Circuit.txt definition

Hello all,

I have several scenarios for GEO plasma environment in order to simulate a charging events encountered by telecommunication spacecrafts.

Actually struggling with some realistic cases and not sure about it if I’m doing this right, since I do not define any circuitry connections between electrical nodes (defined by each surface). Do I either have to ground each node defined on the surface or make them not connected even they have no physical connection in-between? In sunlight conditions for the worst case ECSS plasma environment, solar arrays I defined (ITO coating with 5 sections, over the Y walls) can charge up to 2-3 kV surface potential and kaptons on the X sides (Kapton MLI material properties, no direct photoemission) of spacecraft can charge up to some 10s of kV’s of surface potential. This may result in significant differential charging in dielectrics (I read several papers about the concept).

Best wishes/Regards

Happy new year


Note that electric nodes correspond to the ground of each surface, e.g. for a Kapton MLI it corresponds to the metal (probably some aluminum) layer which is usually grounded to the structure (there is actually a physical connection). It does not correspond to the surface dielectrics. Thus, you should be grounding (connecting with a 0V potential difference: “V Node1 Node2 0V)” these nodes to the spacecraft (or solar panel) ground. Same for ITO, which is generally connected to the ground.

A floating node is SPIS actually means there is physically no connection at all between this node and the others (think at something like two different spacecraft far from each other). On a single platform this can happen for scientific instrumentation or by accident, but should not have application on working telecom platform.

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Dear Sebhess,

Hello, and thank you for the comment, I appreciate this. The assembly procedures of telecom spacecrafts are as well as others, such materials like Kapton, OSR, or any other structure (solar cells are grounded locally as well) must be connected to a spacecraft ground by a physical link. I then have to make a grounding link on each surface node from the ground node if I understand correctly. Thanks.

Best regards

Hello again,

Corresponding to potential differences between the electrical surface nodes at simulation start, I did initiate the 0 V in the spacecraft system (for example; V 0 1 0, 0 is the ground node, 1 is the 1st surface node group, 0 is the initial potential difference - no bias voltage is applied).

For electrical circuit representation of ground in-between the nodes, should I add resistors to spacecraft between surface nodes and ground (for example; R 0 1 1E6 1 MOhm bleed resistor between ground and the 1st surface node group)? I read several papers and information about solar arrays for example.

“… bleed resistors for controlled insulation with the spacecraft body are accommodated on each panel.”

Is it too much detail, or do I need to make a bias voltage as well?

Best Regards

yes if you have a bleed resistor of 1MOhm between the spacecraft ground and the panel ground you should link them exactly as you wrote.

Hello Sébastien, thank you kindly again for the comment.