The Department of Defense's space acquisition enterprise has experienced numerous challenges since the advent of space power. Space borne capabilities are needed more than ever, but space acquisition frequently fails to meet its goals. The decades of space acquisition experience form a rich history that can be used to build a leading indicator of success to enable effective program execution. First, the space acquisition areas of greatest concern were determined to be cost, schedule and requirements. These areas are considered as systems composed of the people, processes and products that execute the program. Second, the vital interoperation characteristics, or attributes that each system must possess to be successful, can be extracted from past space acquisition lessons learned and placed into an interoperability maturity model.