How to do Charging of Multiple Objects/Spacecraft in a Single Simulation?

I would like to know how I can go about modeling and running a simulation that has two separate objects (i.e. two independent spacecraft) within the computational domain. When I try to include a geometry file that has two separate entities SPIS seems to disregard one of them when meshing is done. Is there a way I can set-up the simulation to work with both objects within the same domain?

Would I have to use some trick like connecting both objects with a thin wire (of an insulating material) so that the geometry is technically a single object? How would something like this be done? Or is there some literature I can look into which details the process for such a two-body simulation? Thank you!

Hello Tyler,

I modelled two spacecrafts with a distance of 1m in SPIS 6.1.0. The mesh was done with gmsh and then loaded into SPIS. This way gmsh also gives me more control over the resolution of the mesh in certain areas especially between the spacecrafts than SPIS does. Moreover each spacecraft should have a ground node, so spacecraft A uses node 0 and spacecraft B e.g. node 10, gathering all remaining spacecraft nodes of A and B respectively. Connect both grounds 0 and 10 with a capacity of 15.e-11 (in my case), this will represent the exchange of charges between the spacecraft circuits.

For the global parameters I used a Csat of 3.5E-8 considering the total area of both spacecrafts in LEO-ISS orbit. If one spacecraft is charging slower than the other you can set an initial potential to the affected nodes which will help to speed up the transient phase. The electronDistrib I used was KineticMaxwellBoltzmannVolDistrib and for the ionDistrib the DriftingMBVolDistrib depending on your orbit. I hope this will help you running the simulation, feel free to ask for further parameters.


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Hello Zoe,

I have attempted to replicate your process and have been experiencing circuit solver issues, so I hope you can be of help. I have two questions:

  1. Is node 10 of your example assigned to a physical? And, is that physical a conductor, dielectric, or not even exposed to the plasma?
  2. Is the capacity between grounds 0 and 10 the difference between the capacitance of the two spacecraft?

An example of my circuit is:
SC A ground: Node 0
V 0 1 0
V 0 2 0, etc.

SC B ground: Node 10
V 10 11 0
V 10 12 0, etc.

C 0 10 X

Doing the above consistently leads to a negative array exception. Does this follow with how you’ve been able to solve your cases, or am I missing something?

Thanks in advance,