ROPEC – ROtary PErcussive Coring Drill for Mars Sample Return Philip Chu*, Justin Spring* and Kris Zacny* Abstract The ROtary Percussive Coring Drill is a light weight, flight-like, five-actuator drilling system prototype  designed to acquire core material from rock targets for the purposes of Mars Sample Return. In addition  to producing rock cores for sample caching, the ROPEC drill can be integrated with a number of end  effectors to perform functions such as rock surface abrasion, dust and debris removal, powder and  regolith acquisition, and viewing of potential cores prior to caching. The ROPEC drill and its suite of end  effectors have been demonstrated with a five degree of freedom Robotic Arm mounted to a mobility system with a prototype sample cache and bit storage station.  Introduction The mobility platform for the recently announced surface mission to Mars launching in the year 2020 is  based on the Mars Science Laboratory rover [1]. This rover will conduct rigorous in-situ science  assessments of the Martian surface with the goals of characterizing the local geology, looking for signs of  an ancient habitable environment, and searching for signs of ancient life on the red planet. In addition to these science goals, the Mars 2020 mission will also acquire a number of physical samples, storing them within a sample cache for potential return to Earth at a later stage. These samples will likely include rock cores, regolith samples, and atmospheric gas. The ROtary PErcussive Coring (ROPEC) Drill has been  designed to meet the needs of a Mars Sample Return mission by providing a platform that can produce  rock cores, powder and regolith samples, and can abrade the surface of rocks. This last function servesto remove the weathered layer and expose a fresh rock face similar to the Rock Abrasion Tool on the  Mars Exploration Rovers [2]. These functions are accomplished using a variety of bits, most of which can  then be inserted into a Sample Cache within the rover body for storage.  The ROPEC Drill is the latest in a series of rock coring mechanisms aimed at planetary exploration  developed by Honeybee Robotics over the past two decades [3]. The ROPEC Drill design builds on  previous drilling systems such as the Mini Corer, Corer Abrader Tool, and SASSI Drill; improving upon  them to achieve a light weight, compact, and highly capable mechanism. This drill can be mounted to a  multi-degree of freedom robotic arm similar to the Instrument Deployment Device on the Mars Exploration  Rovers or the Robotic Arm on the Mars Science Laboratory. A robotic arm is used to place the ROPEC drill on the desired rock target, holding the drill in position using a pair of preload tines. The ROPEC Drill then utilizes a rotary percussive action which can penetrate a wide range of rock targets ranging fromhigh strength basalts to highly porous low strength sedimentary rocks. Once the drill has reached its  target depth, an internal mechanism shears the rock core at the base of the drill bit. This shearing action  simultaneously separates the core from the base rock and captures the core within the bit; preventing it from falling out while the bit is retracted from the rock. The entire drill bit, with rock core inside, can then  be delivered to the Sample Cache. This paper focuses on lessons learned throughout the design and development of the ROPEC Drill, as  well as distinctive design features and the decisions and testing that contributed to their final implementation. There are a number of unique design features on the ROPEC Drill which should be brought to the attention of the spacecraft mechanisms community. These features could be used on future space flight mechanisms and prototypes. An overview of the ROPEC Drill and its operational usage *Honeybee Robotics Spacecraft Mechanisms Corporation, Pasadena, CA /g51/g85/g82/g70/g72/g72/g71/g76/g81/g74/g86/g3/g82/g73/g3/g87/g75/g72/g3/g23/g21/g81/g71/g3/g36/g72/g85/g82/g86/g83/g68/g70/g72/g3/g48/g72/g70/g75/g68/g81/g76/g86/g80/g86/g3/g54/g92/g80/g83/g82/g86/g76/g88/g80/g15/g3/g49/g36/g54/g36/g3/g42/g82/g71/g71/g68/g85 /g71/g3/g54/g83/g68/g70/g72/g3/g41/g79/g76/g74/g75/g87/g3/g38/g72/g81/g87/g72/g85/g15/g3/g48/g68/g92/g3/g20/g23/g16/g20/g25/g15/g3/g21/g19/g20/g23/g3 195