Abstract: After decades of study, the physical processes regulating star formation remain poorly understood. In particular, the role played by magnetic fields in both the formation of molecular cloud structure and the regulation of core collapse is unclear. In many simulations, magnetic fields dramatically affect both the star formation efficiency and lifetime of molecular clouds. However, observationally the strength and morphology of magnetic fields in molecular clouds remain poorly constrained. Submillimeter polarimetry provides an important observational window on magnetic fields in star forming regions. By mapping polarized emission from dust grains aligned with respect to their local magnetic field, the field orientation (projected on the sky) can be traced. The Next-Generation Balloon-borne Large Aperture Submillimeter Telescope (BLAST-TNG) is a 2.5 meter submillimeter polarimeter designed to map magnetic fields. BLAST-TNG utilizes three polarization-sensitive arrays of over 4000 microwave kinetic inductance detectors, centered at 250, 350, and 500 microns. BLAST-TNG will provide an unprecedented number of magnetic field vectors, and will enable a rigorous statistical analysis of the role that magnetic fields play in star formation. I will present the overall design and progress towards deployment of both the detector arrays and readout hardware in anticipation for a December 2016 BLAST-TNG Antarctic flight.