Robotics Capabilities Development for Mars Sample Return Transfer Activities

The planned NASA-European Space Agency (ESA) Mars Sample Return campaign aims to be the first set of missions to bring Martian samples back to Earth, where thousands of scientists would make groundbreaking discoveries that could redefine our understanding of the Red Planet and perhaps even the origins of life on Earth. A crucial component of the circa 2023 baseline design for the missions was the transfer of sample tubes from the Martian surface to the ascent vehicle, which requires a highly dexterous robotic arm and sophisticated control strategies. Development and testing of the control algorithms were underway at NASA's Jet Propulsion Laboratory on advanced R&D testbeds, while the ESA is responsible for delivering the flight robotic arm. To meet the complex requirements for transferring the sample tubes, we propose an abstract layer consisting of three important robotics capabilities, each to be implemented for the first time in planetary exploration. 1. 7-DoF Manipulation: This capability focuses on managing the kinematics of the 7-DoF robotic arm. It includes the development of algorithms for forward and inverse kinematics, joint redundancy management, kinematic calibration, deflection compensation, target-to-pose selection, trajectory generation, and control strategies for single-joint, multi-joint, Cartesian motions, and free-space closed-loop control. 2. Robotics Vision: This capability pertains to a monocular vision system mounted on the robotic arm's end-effector with an additional redundant camera. These cameras are essential for localizing the Mars 2020 rover (M2020) tube-retrieval station, the SRL OS, identifying tubes on the Martian surface, and estimating the robotic arm's pose to ensure successful interactions with the station. 3. In-Contact Manipulation: This capability addresses the robot's interaction with its external environment. It involves load estimation using a 6-DoF force-torque sensor, force regulation (standard load-wrench control to a setpoint), and hybrid motion (force regulation orthogonal to a baseline velocity). This paper documents for posterity the infusion of these robotics capabilities, including the requirements, analysis, and testing processes that would have been necessary to ensure the success of the circa 2023 SRL Sample Transfer System design.