OBJECTIVES: THE GOALS OF THE PROPOSED INVESTIGATION ARE TO DESIGN AND TEST AN MR GRIPPER FOR USE ON-ORBIT AND CHARACTERIZE ITS POWER AND CONTROL REQUIREMENTS ON THE HOST SPACECRAFT. SPECIFICALLY WE WILL: 1. EXPERIMENTALLY EVALUATE THE EFFECTIVENESS OF THE PROPOSED GENERAL MR GRIPPER DESIGN AS A FUNCTION OF A VARIETY OF DEVICE CHARACTERISTICS. 2. MODEL THE DYNAMICS OF OBJECT INSERTION} IN ORDER TO DEFINE THE OPERATIONAL CONSTRAINTS OF THE DEVICE. 3. CALCULATE THE MASS POWER AND VOLUME REQUIREMENTS FOR THE MOST EFFECTIVE DEVICE CONFIGURATIONS. METHODOLOGY: WE WILL EXPERIMENTALLY MEASURE THE FORCE REQUIRED TO EXTRACT CYLINDRICAL TEST OBJECTS FROM MR GRIPPERS WITH A VARIETY OF DESIGN CHARACTERISTICS. WE WILL VARY THE MR INTERSTITIAL FLUID THE GRAIN CHARACTERISTICS THE FILLING FRACTION OF THE GRIPPER THE TEST OBJECT SIZE AND THE APPLIED MAGNETIC FIELD STRENGTH. BIOCOMPATIBLE MR FLUIDS WILL BE USED FOR SAFETY IN ISS OPERATIONS SHOULD A LEAK DEVELOP. WE WILL ALSO MEASURE THE MASS POWER AND VOLUME REQUIREMENTS OF THE PROTOTYPE GRIPPERS. WE WILL NUMERICALLY MODEL THE INSERTION OF THE TEST OBJECT INTO THE GRIPPER USING A SOFT-SPHERE DISCRETE ELEMENT METHOD CODE. THE CODE WILL MODEL THE DEFORMABLE GRIPPER MEMBRANE AS A SHEET OF GRAINS WITH CONSTANT CONTACTS.