THIS PROJECT WILL DELIVER A LIGHTWEIGHT AND COMPACT PROTOTYPE ROBOT-BASED EXERCISE DEVICE. THE CURRENT GRASSHOPPER TESTBED DEVICE WHICH HAS UNDERGONE PRELIMINARY TESTING AND DEVELOPMENT WILL BE USED TO ACCELERATE DEVELOPMENT. THE DEVICE WILL SUPPORT SEVERAL DIFFERENT EXERCISES INCLUDING ANAEROBIC AND AEROBIC. BY USING MOTORS THAT ARE COMPUTER CONTROLLED THE APPLIED RESISTIVE FORCES AND CAN BE ADJUSTED ALMOST INSTANTANEOUSLY. IT WILL BE POSSIBLE TO CONNECT A TOUCHSCREEN-BASED USER INTERFACE WILL ALLOW THE USER TO SELECT THE EXERCISE AND SETTING AND PROVIDE REAL-TIME FEEDBACK DURING THE ACTIVITY. DESPITE BEING SMALL COMPACT AND LIGHTWEIGHT THE DEVICE WILL BE CAPABLE OF PROVIDING A COMPLETE CUSTOMIZED STRENGTH AND AEROBIC WORKOUT WITH FEATURES NOT AVAILABLE ON ANY COMMERCIALLY AVAILABLE EXERCISE EQUIPMENT. THE DEVICE WILL COME WITH AN API FOR DEVELOPERS TO PROGRAM DIFFERENT TYPES OF EXERCISE. PROLONGED EXPOSURE TO MICROGRAVITY HAS BEEN SHOWN TO HAVE DELETERIOUS EFFECTS ON THE ENTIRE HUMAN MUSCULOSKELETAL SYSTEM. SPECIFICALLY LONG DURATION SPACEFLIGHT ADVERSELY AFFECTS THE MASS AND STRENGTH OF ASTRONAUTS MUSCLE AND BONE. THE CURRENT COUNTERMEASURES FOR REDUCED MUSCLE MASS AND STRENGTH INCLUDE A ROUTINE IN-FLIGHT EXERCISE PROGRAM. ONE OF THE MOST UTILIZED EXERCISE DEVICES IS CALLED THE ADVANCED RESISTIVE EXERCISE DEVICE (ARED) WHICH IS CURRENTLY IN PLACE ON THE INTERNATIONAL SPACE STATION (ISS). ALTHOUGH ARED IS CURRENTLY AN IMPORTANT COMPONENT IN MITIGATING MUSCLE LOSS AND BONE MINERAL DENSITY (BMD) REDUCTION IT IS FUNDAMENTALLY INCOMPATIBLE WITH MISSION SCENARIOS USING THE MULTI-PURPOSE CREW VEHICLE (MPCV) OR SIMILAR SPACECRAFT. THROUGH SIMPLE AND EASY RECONFIGURATION THE DEVICE WILL BE ABLE TO ACCOMMODATE 1ST-99TH PERCENTILE POPULATION TO PERFORM UPPER BODY LOWER BODY AND FULL BODY AEROBIC AND ANAEROBIC EXERCISES. IN ADDITION WE BELIEVE THAT THIS DEVICE WILL OFFER AN EXERCISE REGIMEN THAT IS SUPERIOR TO ARED AS WELL AS MOST GRAVITY BASED GYM EQUIPMENT. BECAUSE THE RESISTIVE FORCE THE DEVICE CREATES IS GENERATED BY MOTORS AND IS COMPUTER CONTROLLED AT THOUSANDS OF TIMES PER SECOND THE FORCE CAN BE CHANGED INSTANTANEOUSLY. THIS ALLOWS THE ECCENTRIC TO CONCENTRIC LOAD RATIO TO VARY FROM ZERO TO INFINITY DEPENDING ON THE EXERCISE PRESCRIPTION. IN ADDITION THE PROPOSED DEVICE CAN BE USED FREE FLOATING REMOVING THE NEED FOR VIBRATION ISOLATION FROM THE SPACECRAFT STRUCTURE. BECAUSE THE DEVICE WILL BE INSTRUMENTED WITH A FULL COMPLEMENT OF SENSORS TO MEASURE THE FORCES POSITIONS LOADS THIS LARGE AMOUNT OF DATA FROM THE DEVICE WILL HELP EXERCISE PHYSIOLOGISTS CONTINUE TO UNDERSTAND AND SOLVE THE CHALLENGES OF MAINTAINING CREW HEALTH IN SPACE.