If you're going to use Particular anyway, discard the 3D light and use particular. You'll save yourself a lot of problems.
Particular allows you to use a light to control an emitter, which is probably why the OP is using one.
If you can position a null or a hidden solid in 3D space to approximate the plane on which the rocket is moving, you can use expressions to project the position of the null out and onto the plane. Use a position expression on your light that goes something like this:
N = thisComp.layer("Null 1");
plane = thisComp.layer("Solid 1");
Substitute the name of your null for "Null 1", and the name of the null or solid that represents the 3D plane on which you want the light to move for "Solid 1". This expression assumes the tracked null isn't parented to anything. If it is, you'll need to transform the null's position to comp space before transforming from comp to surface.
ETA: Thinking about what you are doing more, you are probably tracking the background, not the rocket, which means you really want to have your 3D camera pivoting to mimic the camera shake, so you can make your rocket move naturally within the scene. The same idea applies, but instead of trying to set up a plane for the rocket's path, you'll want to set up a plane at the simulated distance of the scene element you are tracking, then auto-orient the 3D camera either to that object, if it is at the center of the view, or to a child object placed at the center of view.