The Balloon-Borne Cryogenic Telescope Testbed (BOBCAT) is a technology demonstration to develop advanced instrumentation for astrophysical observations at far-infrared wavelengths. It develops cryogenic techniques as an enabling technology to improve far-IR sensitivity by a factor of 100,000 or more compared to current state-of-the-art instrumentation such as SOFIA. Cryogenic spectrometers, operating at balloon altitudes, have game-changing capabilities, but achieving this goal while remaining within balloon payload mass limits requires ultra-light cryostats. This project develops the ultra-light cryostat and demonstrates the ability to transfer cryogenic liquids at balloon altitudes.