Comet Dynamics II

So I finished the comet model for now (for a second time). I have reduced how long the model takes to run again from 33 seconds to 14 seconds by taking out the cross function and replacing it with the direct equation.

Changes from the last post:

• Variable inertia matrix

The inertia matrix now changes with the ejected mass. This makes the simulation more realistic. However, the shape of the comet does not change (ie. the change in mass does not change the comet thickness). 

• Random off-gassing jet placement and variable composition

Instead of off-gassing jets being able to be produced on every face, now the chance that a jet will be on a specific face is randomized (I currently have it at a 5% chance). The composition of those faces are then randomized at a maximum of 5% of the face being volatilizes. This also effects the initial inertia matrix.

One implication of this is with constant face jets, the comet usually will spin up along a specific rotation axis. This can be seen in the following video. The great thing is that the axis it settles on does not have the be a major or minor axis due to the off-gassing thrust.

Black line: Rotation axis.

Yellow line: Sun vector .

Comet Color: Proportional to temperature (Red is hot).

Dark blue line: Total force on body.

Rings: Torque direction (green is +, red is -) and normalized magnitude. 

Light blue lines: Direction and normalized magnitudes of off-gassing jets.