In the last two decades, the mathematical analysis of material transport has received considerable interest in many scientific fields, in particular in astrodynamics. In this contribution we will focus on the numerical detection and approximation of transport barriers in the solar system. For this we consider and combine several techniques for the mathematical treatment of transport processes-using both continuous concepts from dynamical systems theory and discrete ideas from graph theory. For the demonstration of our results we consider the planar circular restricted three body problem with Sun and Jupiter as primaries, a simple model for describing the motion of asteroids in the solar system.