This paper presents a preliminary modeling method, Habitat Multivariate Design Model (HMVDM), to estimate the volume, size, shape, and configuration required for the design of a space habitat. The specific habitat used for this analysis is the "Habot" mobile lunar base concept.The HMVDM methodology begins with values for mass and volume from quantitative summation tools such as the NASA Office of Biological and Physical Research (OBPR) Crew Accommodations Guide. From these tools, it derives a more detailed analysis of mass and particularly of volume. The estimated volume is input into the model, written as a spreadsheet-based analytical modeling tool. In this pilot study, the diameter of a cylindrical module serves as the single independent variable. The dependent variables include: the number of pressure ports, the floor area, the height of the end dome, the height of the cylindrical portion of the module, the number of floor decks, the floor to floor height, and the volume of vertical circulation.The model affords an array of adjustable evaluation criteria and set point limits to assess the results in the dependent variables. This evaluation provides the ability to analyze the independent variable for which values meet the "requirements" of the mission and habitat design.