The infrared Absolute Radiance Interferometer (ARI) prototype instrument was developed for NASA's Climate Absolute Radiance and Reflectivity Observatory (CLARREO), and brought to a Technical Readiness Level (TRL) of 6 by the University of Wisconsin Space Science and Engineering Center (UW-SSEC) and the Anderson Group at Harvard University, with funding from the NASA Earth Science and Technology Office (ESTO). A summary of the demonstrated radiometric performance, and the current instrument status is presented.