Dynamic reconfiguration during simulation

[AdamDorwart]

I'm trying to design a mission where a spacecraft has payloads that detach and become independent bodies/spacecraft. Even better I could then join spacecraft to other spacecraft to simulate docking/assembly.

I've taken a look through the code and AFAIK this is currently not possible with the current spacecraft/bodies/joints implementation. Furthermore it's not trivial to add because the underlying dynamics seems like it assumes static configurations. Before I move on I just wanted to confirm that I didn't overlook some existing capability.

[ericstoneking]

Hi Adam,

There may be a couple of approaches, depending on how independent you want your splinter S/C to be.

1. 6DOF joints are supported, and all joint DOFs can be locked/unlocked on the fly. Define a two-body S/C with the joint DOFs locked, and it behaves as a single body. Unlock the joints, and the bodies separate. It will still be considered a single S/C, just with disconnected bodies.

2. S/C existence (see Inp_Sim.txt) can be toggled on the fly. Define S/C A, S/C B, and S/C A+B. Initially, A+B exists and A and B don't. When you want to separate, set SC[A+B].Exists to FALSE, and SC[A].Exists and SC[B].Exists to TRUE. You will need to write your own code to match the dynamic states accurately.

I've never had the occasion to do it, but the SC array of structs is dynamically allocated, so could be resized during a run. It would be up to you to properly populate any new S/C you add.

Regards,
-Eric