Presentation #202.02 in the session Planetary Interiors.
The community uses a variety of models to characterize the interior structure of small planets. Underlying these models are multiple computational techniques, numerous experimental measurements and theoretical estimates of the equations of state for planet-building materials, and differing treatments of temperature. MAGRATHEA is an open-source interior structure solver which can be customized to user-defined planet models. Our code features adaptable phase diagrams for the core, mantle, hydrosphere, and atmosphere and transparent formatting for equations of state. I demonstrate how the community can use and contribute to the code. I then use MAGRATHEA to test model parameters and quantify systematic uncertainties in the characterization of small planets such as those in the Trappist-1, K2-138, and K2-146 systems.