The Envelope Systems Research Apparatus (ESRA) is an ongoing research project at the College of Architecture of The University of Arizona to develop a sustainable, adaptable and mobile laboratory . The goal of ESRA is to promote the learning of energy efficiency while exploring the unique aspects of the thermal properties of advanced building envelope systems and passive solar designs and technologies. The project demonstrates innovative structure deployment systems capable to adapt to a variety of sites and conditions. Viewers and visitors can understand first hand through testing and demonstration what a sustainable, flexible, and mobile structure can achieve. On sustainability, ESRA will be designed to a high standard of energy efficiency levels while it will be capable of testing many other types of green and energy efficient building materials. For flexibility, it will experiment with an adaptable structure that will be deployed with ease, expanding the areas of its indoor spaces, while transforming the adjacent outdoor spaces to thermally comfortable places capable of accommodating different extended activities. The envelope itself will mediate the microclimate through passive design strategies such as ventilation, evaporative cooling, solar heating and light. The mobility aspect of ESRA allows it to travel to diverse or remote destinations while the structure is demonstrating how such transportable environment can serve for living, working, learning, servicing and assisting a variety of functions. On October 25, 2002 an agreement was made between the University of Arizona's Design and Energy Conservation faculty and Southwest Gas Corporation to develop ESRA. The mobile unit will make up part of a larger Building Envelope Research Center at the School of Architecture grounds. The proposed project will also help in developing strong relationships with all the building-sector participants, including manufacturers, utilities, community organizations, professional societies, other universities, and state and local governments. This paper describes the design development of ESRA and demonstrates the mechanics of how a mobile lab can be transported to, maneuvers around, and how it takes advantage of site amenities. This paper also describes the proposed materials for use in the construction and why they were chosen along with the testing of the mechanical equipment and the energy simulation results.