[Orekit Users] Add force models during propagation

["John Reilly" <reilly@barronassociates.com>]

I have inherited a large program built upon Orekit a long time ago. I'm trying
to architect the best way to add a feature.

What we need to do is to add force perturbations during propagation. Right
now, I have an event detector which, at the appropriate time, calls an
external process to request control forces. The way I understand it, the usual
path would be for me to add a ForceModel to the numerical propagator at
configuration, prior to propagation starting. At propagation start, the
propagator would then ask the ForceModel for start/stop event detectors. Since
my control forces are unknown a priori, I cannot do this. (I don't think).

I would appreciate advice on how to best accomplish my goal. Should I just add
ForceModel objects to the propagator at runtime, and then have them manage
their own time, so that they return the forces during the proper time span,
and zero otherwise? Or should I add some kind of force model aggregator that I
invent, that itself contains the list of runtime-generated ForceModel objects?
Or does Orekit already provide a solution?

I appreciate your advice.

-John Reilly.