This paper discusses the process by which the initial system concept design for a remotely operated Tumbling Satellite Retrieval System (TSRS) was developed. This kit, when attached to the Orbital Maneuvering Vehicle (OMV), will retrieve spacecraft whose motion or interfaces prevent direct capture by standard OMV attachment hardware. The system concept design, which was defined by mission, system, and functional requirements, was developed under a NASA/MSFC contract, the objective of which is the development of an evaluation test article. (Detailed design and validation tests will follow.) The process started with the development of twelve “design reference mission” (DRM) retrievals. The twelve DRMs were developed from analysis of the physical and dynamic characteristics of existing and planned spacecraft. Potential TSRS configurations were then developed for accomplishing each DRM. These configurations were winnowed down to a select few based on their relative merit in satisfying system selection criteria such as weight, technical readiness, probability of mission success, launch volume, etc.