This paper will summarize the study that was conducted under the auspices of the National Aeronautics and Space Administration (NASA), lead by Johnson Space Center's Engineering Directorate in support of the Lunar Lander Preparatory Study (LLPS) as sponsored by the Constellation Program Office (CxPO), Advanced Projects Office (APO). The lunar lander conceptual design and analysis is intended to provide an understanding of requirements for human space exploration of the Moon using the Advanced Projects Office Pre-Lander Project Office selected “HabiTank” Lander concept. In addition, these analyses help identify system “drivers,” or significant sources of cost, performance, risk, and schedule variation along with areas needing technology development. Recommendations, results, and conclusions in this paper do not reflect NASA policy or programmatic decisions. This paper is an executive summary of this study. The detailed technical lander concept report is documented in the ‘Lunar “HabiTank” Lander Element Conceptual Design Report,’ JSC-63600 (in process of being released).