The Algae Testbed Public-Private Partnership (ATP3), led by Arizona State University, is a partnership of universities, commercial enterprises and national laboratories supported by DOE funding with the primary purpose of creating a geographically diverse network of algal biomass production testbed facilities, support infrastructure, and expertise to work with industry and the broader R&D community to accelerate applied algal research, technology development, and commercialization for biofuel feedstock production. Since getting underway in early-2013, ATP3 has been establishing the organization, data and IP management systems, and standardized data collection and analysis procedures and processes for conducting objective algae testbed operations, biomass production and analysis, and user collaboration at six geographically-diverse U.S. partner locations. Sandia National Laboratories (SNL) and the National Renewable Energy Laboratory (NREL) are specifically contributing innovative diagnostics, modeling, and analysis capabilities to the partnership and the broader testbed user community. This presentation provides a high-level overview of ATP3 and several specific diagnostic, modeling, and analytical technologies and capabilities that have been developed over the past few years at SNL and are also being applied in support of algae biofuels RD&D through ATP3. This includes advanced algae cultivation diagnostics and cultivation crash forensics using metagenomics, physicis-based algae cultivation system modeling with current focus on open raceway ponds, and broad-band spectrally-resolved optical reflectance measurement instrumentation and data processing algorithms for quasi-real-time non-invasive monitoring of cultivation performance. Also described is work by ASU and NREL to establish harmonized algae biomass cultivation trials and standardized biomass testing and biochemical analyses across multiple test sites.