The Working Group Meeting on New Standard Radiation Belt and Space Plasma Models for Spacecraft Engineering, sponsored by NASA's Living With a Star (LWS) program, met on October 5--8, 2004 in Adelphi, Maryland to begin rebuilding the infrastructure required to develop new space radiation belt and plasma models. The decades-old AP-8 and AE-8 models contain inaccuracies due in part to the limitations of the data-collecting instruments available at the time, as well as extrapolations in time, space, and energy spectra that were required to cover measurement gaps when they were initially developed. As a result of these inaccuracies, mission designers tend to overestimate the expected operational radiation environment, leading to costly over-design of space systems.