This document summarizes James Howison's research on sustaining scientific software projects after grant funding ends by transitioning them to peer production. The research involves case studies of scientific software projects that received NSF funding to examine how they successfully or unsuccessfully transitioned to thriving open source communities. The case studies analyze actions taken to change projects' governance, collaboration processes, and contribution routines. An initial case study of the ENZO astrophysics simulation code is presented, identifying four phases of the project precipitated by events that changed its socio-technical structure and collaboration practices over time. The research aims to identify conditions and strategies that facilitate successful transitions of scientific software projects to sustainable peer production.