As part of the Commercial Orbital Transportation Services (COTS) Phase I development program, NASA has initiated two development programs (SPACEX and Rocketplane/Kistler) to develop new launch vehicles and associated cargo and crew transportation spacecraft. NASA has encouraged other spacecraft developers to continue development of alternate systems that could compete for follow-on ISS cargo contracts after the conclusion of the COTS Phase I program. With this in mind, SPACEHAB/Astrotech is developing the Astrotech Research & Conventional Technology Utilization Spacecraft (ARCTUS) concept. The main goals of the ARCTUS program are to minimize risk, development schedule and cost by utilizing as many existing components and systems as possible. The ARCTUS philosophy will minimize non-recurring development costs as well as eliminate unnecessary financial and technical risks (e.g. the development of a new launch vehicle). ARCTUS will utilize existing components from the Centaur Upper Stage as well as other existing spacecraft hardware and be flown on existing U.S. based launch vehicles. In its smallest configuration, ARCTUS accommodates up to 3 mT of ISS external Orbital Replacement Units (ORUs) as well as providing accommodations for 1.9 mT of pressurized cargo. Low G reentry capability is provided using LARC IRVE inflatable heat shield technology combined with mid-air helicopter retrieval for the lowest cost, lowest G level retrieval system, and highest return mass fraction possible. This is likely the lowest cost, lowest risk approach to the COTS proposal to date.