SAM: Construction of a hi-fidelity, hermetically sealed Mars habitat analog at Biosphere 2. Author: Kai Staats, project lead, SAM at Biosphere 2 Description: A Space Analog for the Moon and Mars (SAM) is a hi-fidelity, hermetically sealed analog and research center composed of a living quarters for four inhabitants, airlock and hub, and greenhouse with temperature, humidity, and carbon dioxide level controls. When complete, SAM will include a half-acre Mars yard for pressure suit, tool use, and rover tests; a constructed lava tube and gravity-assist rig for reduced gravity simulations. In 1987 Taber MacCallum and William Dempster designed and build the now iconic Test Module, a sealed greenhouse prototype used to test the fundamental functions of the structure and lung used to build the massive Biosphere 2. Now, project lead Kai Staats, Trent Tresch, John Adams and a compliment of volunteers are constructing SAM with intent to welcome the first research teams in the fall of 2021. SAM design and development is guided by experts at NASA Johnson Space Center, Grant Anderson, CEO of Paragon SDC; Dr. Murat Kacira and Dr. Gene Giacomelli at the Controlled Environment Agriculture Center at the University of Arizona, and original Biospherian Taber MacCallum. In this presentation Trent will engage the audience in the construction process, lessons learned, and the long-term goals of this unique research facility as it relates to sealed habitats of any volume or duration, and how SAM will inform the computer model SIMOC with a long-term goal of management of on-board life support systems. Objective: To build a habitat analog and research station that welcomes research teams from around the world, to help prepare our species to become interplanetary. Methods: Grinder, sander, scraper, primer and paint; electrical wiring, lighting, HVAC. CO2 scrubber, pressure seals, monitors and regulators, pressure suits and EVAs. Results and Conclusions: To be determined!