The Lead Proposal for this investigation originates from the University of Arizona, Steward Observatory under Principal Investigator Dr. Christopher K. Walker. The Smithsonian Astrophysical Observatory (SAO) is pleased to submit this subsidiary proposal for engineering and scientific collaboration on the reflight of the Stratospheric TeraHertz Observatory (STO-2). This proposal covers Support for 4th Year Operations, Recovery, and Science as a result of the failure to launch due to weather in the 2015-2016 season. The Institutional Principal Investigator for the SAO effort is Antony A. Stark, and scientific Co-Investigators Gary Melnick, Volker Tolls, and Matthew Ashby. SAO will provide pre-flight engineering and flight monitoring support for the second Long Duration Flight (LDF) from McMurdo Sound in Antarctica. Subsequent to the flight, SAO Co-Is will contribute to data management and analysis, scientific interpretation, publication of results, and public distribution of data.