# Principle - penalty-based methods use a virtual spring–damper model to apply restoring forces at the point of deepest penetration between bodies in contact [[cite_mylapilliComplementarityTechniquesMinimal2017a]]. # Issues - Penalty-based methods notoriously suffer from oscillatory effects and become numerically unstable when bodies collide with a high velocity [[cite_mylapilliComplementarityTechniquesMinimal2017a]]. This would make them unsuitable for debris spacecraft collisions. - Small time steps and excessively damped implicit integrators are used to counter these problems, which makes the method slow and computationally expensive.