Application of a Novel Long-Reach Manipulator Concept to Asteroid Redirect Missions

Abstract

A high priority mission currently being formulated by NASA is to capture all or part of an asteroid and return it to cis-lunar space for examination by an astronaut crew. Two major mission architectures are currently being considered: in the first (Mission Concept A), a spacecraft would rendezvous and capture an entire free flying asteroid (up to 14 meters in diameter), and in the second (Mission Concept B), a spacecraft would rendezvous with a large asteroid (which could include one of the Martian moons) and retrieve a boulder (up to 4 meters in diameter). A critical element of the mission is the system that will capture the asteroid or boulder material, enclose it and secure it for the return flight. This paper describes the design concepts, concept of operations, structural sizing and masses of capture systems that are based on a new and novel Tendon-Actuated Lightweight In-Space MANipulator (TALISMAN) general-purpose robotic system. Features of the TALISMAN system are described and the status of its technology development is summarized. TALISMAN-based asteroid material retrieval system concepts and concepts-of-operations are defined for each asteroid mission architecture. The TALISMAN-based capture systems are shown to dramatically increase operational versatility while reducing mission risk. Total masses of TALISMAN-based systems are presented, reinforcing the mission viability of using a manipulator-based approach for the asteroid redirect mission. NomenclatureACS = asteroid capture system ARM = asteroid redirect mission cg = center-of-gravity ConOps = concept of operations EB = enclosure bag EVA = extra-vehicular activity GCD = game changing division HRS = human robotics systems MATLAB = MATrix LABoratory (software suite) NEA = near-Earth asteroid PMC = polymeric composite RFI = request for information SOA = state-of-the-art SRMS = Shuttle remote manipulator system SSRMS = Space Station remote manipulator system TALISMAN = Tendon-

Structural Sizing Methodology for the Tendon-Actuated Lightweight In-Space Manipulator (TALISMAN) System

“…Packaged volume may also be important for a particular mission, thus more shorter links may be advantageous over fewer, longer links. The most recent design study for which TALISMAN sizing was performed was for the Asteroid Redirect Mission (ARM) Concept B 4 . This mission architecture employed three TALISMANs as grapple arms to pick up a boulder on the surface of a 100 m class asteroid, and three additional TALISMANs as landing legs to enable a soft touchdown on, and push-off from, the asteroid.…”

“…These benefits include the mechanical advantage provided by the spreaders that offset the tension elements at the joints, reducing the required motor size and providing geometric stiffness in the plane of the spreaders; and the simplicity of the structural design that allows rapid analytical modeling and sizing. TALISMAN, like the LSMS, provides multi-mission capabilities, with applications including asteroid retrieval and manipulation, in-space servicing, and astronaut and payload positioning [3][4][5] . Given this mission versatility, a structural sizing methodology was developed to rapidly assess mass and configuration sensitivities for any specified operational work space, applied loads and mission requirements.…”

Control System Design Implementation and Preliminary Demonstration for a Tendon Actuated Lightweight In-Space MANipulator (TALISMAN)

“…In order to enable future missions and applications, it is desirable to improve space manipulator state-ofthe-art by significantly increasing manipulator reach, dexterity and packaging efficiency while reducing manipulator mass and complexity. The Tendon Actuated Lightweight In-Space MANipulator (TALISMAN) 3,4 is an innovative new robotic manipulator architecture that incorporates a tendon-actuated joint with a novel hinge that allows a full 360-degree rotation between connecting links and the capability to incorporate auxiliary and passive tension stiffening. Tendon actuation incorporates spreaders to achieve longer moment arms between the force applied by tension cables and the joint rotation axis, thus gaining mechanical advantage for generating moments and actuating the joints.…”