The Terrestrial Planet Finder Interferometer Project (TPF-I) has set for itself a host of challenging technical milestones along its path to demonstrating the feasibility of infrared nulling for planet detection. Our activities are focused solely upon the experimental demonstration that deep nulling in the mid-IR over a wide bandpass can be accomplished. Specifically, we have the near-term goal of demonstrating a contrast of 10-6 at 10 μm with a 25% spectral bandwidth. To meet these goals, several areas of technical development are required. These include: single-mode infrared fibers, bright infrared sources, laser path-length and tip/tilt metrology, and improvements to null detection. Progress in each of these areas of technical development will be reviewed as well as their impact on the overarching technical milestones.© (2005) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.