Spaceflight adaptations include muscle atrophy, decreased bone mineral density and reduced aerobic capacity making effective resistance exercise countermeasure hardware necessary for safe and successful space exploration. Real-time control is applied to an electric servo-motor to provide resistance in a lightweight, compact, and reconfigurable design. The key real-time force control with the ability to accurately simulate a freeweight lift was successfully demonstrated during Phase 1. A cycle ergometer will be integrated into the system to provide aerobic exercise and power generation. The technical objectives for Phase 2 include the development of a compact flight configuration prototype that supports a variety of exercise modes. The loads are adjustable in 2.5 kg increments to maintain muscle strength and bone density. Limited human subject testing will demonstrate functionality spanning entire anthropometric range.