Silicate melts play a dominant role in the evolution of rocky planets, shaping the planet's compositional trajectory through every phase of its lifetime. Magmas and lavas act as primary agents of chemical transport and evolution, a direct consequence of their high reactivities and mobilities (which arise from their atomic-scale structures and dominate their physical properties). Magmatic evolution is primarily responsible for the great diversity of rock types throughout terrestrial planets, determining how even highly similar mantle compositions can yield the wide variety of rock types seen throughout the solar system. Simultaneously, the thermodynamics of multi-phase melting and crystallization is largely responsible for the structures of rocky planet interiors. Additionally, the primitive outgassed atmospheres of rocky planets are controlled by the chemical thermodynamics of silicate melts, a key insight for predicting and interpreting the atmospheric compositions of rocky exoplanets.

I will present thermodynamic modeling tools and simulation studies of silicate melts created as a lead developer on the ENKI project team (www.enki-portal.org). We will discuss an array of open-source modeling tools---designed for use in research and the classroom---that are being used to understand many of the major stages of rocky planet formation and evolution. These tools build upon thermochemical models of oxide & silicate minerals and melts, together with models for gaseous species and aqueous fluids. We will touch on a variety of rocky planet applications including the formation of their interiors and evolution of their surfaces & atmospheres. Finally, we will discuss ongoing efforts to dramatically improve the accuracy & scope of these modeling tools through the development of new thermochemical liquid models (MELTS 2.0 & exoMELTS) focused on capturing the effects of composition and pressure on silicate melting, with a specific aim toward describing the expanded diversity of planetary possibilities outside our solar system.