RoboSuit: Robotic Augmentations for Future Space Suits 2004-01-2292
Space suit design has been limited to evolutionary steps since the first pressure suit was developed in 1934. While this development process has improved the fit to the wearer, it is still common to measure the performance of a pressure suit by identifying what fraction of shirtsleeve capability it allows. Given sufficient government and commercial support, space could in the future be an expanding realm of commercial and exploration activities, including return to the moon and human Mars exploration, with requirements for extravehicular activity orders of magnitude beyond the maximum envisioned for the International Space Station era. In such an environment, the need for breakthrough technology is to make the space suit into an augmentation of the human wearer, rather than an impediment. This paper details relevant past research and several near-term approaches to the development of a “RoboSuit”: a space suit system than makes the wearer more capable than a human in shirtsleeves, rather than less. Ultimate forms of RoboSuit will include augmentations of the wearer's sensory inputs (tactile, multispectral visual, proximity, proprioceptive, aural) and cognitive functions (knowledge bases, navigation data, adaptive task planning); however, the primary focus of this paper will be to identify approaches to augmenting physical capabilities through the incorporation of robotic manipulators as auxiliary hands and arms, or eventually the use of robotic augmentation of suit joints to provide direct human force amplification upon command.
This paper covers three evolutionary approaches to integrating robotic technologies directly into a space suit to augment current capabilities. As a first step, lightweight manipulators can be added to support systems used with the suit to provide third and fourth “hands” in performance of the EVA tasks. Results will be presented from testing this concept with existing robots in the University of Maryland Space Systems Laboratory, leading to a summary of the system which was under development to augment Hubble Space Telescope servicing productivity, prior to the cancellation of the SM-4 mission. The Hubble EVA/Robotic Utility for Logistics and Experiment Servicing (HERCULES) incorporated two dexterous robotic manipulators with interchangeable end effectors into the EVA manipulator foot restraint on the end of the shuttle Remote Manipulator System (RMS). This system can work directly as a teleoperator prior to and after crew EVAs, preparing and closing out work sites, prepositioning tools and orbital replacement units, and allowing the crew to focus on the high-dexterity tasks best suited to humans. During EVA, the manipulators would be used in direct support of the suited astronauts, carrying and positioning tool boards, transporting replacement modules to reduce translation times during EVA, and generally acting as an assistant to the crew. The detailed design of HERCULES will be described, along with analytical results showing that this system can reduce the 30 hours of baseline EVA planned for SM-4 down to 17 hours.
As the logical next step, the paper discusses migrating the robotic manipulators off of the EVA support equipment and directly onto the space suit. There are several current approaches to this manipulator-integrated space suit. The simplest is a robotic “backpack” to be worn over the portable life support system of the current extravehicular mobility unit (EMU), providing a pair of lightweight dexterous manipulators that can be used for active body restraint and stabilization, carrying tools and equipment, or actually performing assembly and servicing tasks under direct EVA control. A more ambitious version of this is the Space Construction and Orbital Utility Transport (SCOUT) concept, wherein a small pressurized spacecraft provides mobility and comfortable habitability for a single operator in extended missions. A conformal helmet/upper torso/suit arm arrangement in the pressurized cabin allows the operator to directly interact with the work site in a similar manner to current EVA, augmented by two dexterous manipulators and a grappling arm. This system, which has been designed in detail, would be ideal for deep-space EVAs for missions or stations beyond low earth orbit.
The final system described, which can be truly called “RoboSuit”, is a more traditional space suit incorporating direct robotic torque augmentation in each joint. Starting from a rotary-joint hard suit concept such as the NASA AX-5, RoboSuit would provide selectable augmentation of each body segment, adjustable from merely canceling out joint torques or suit weight on planetary surfaces, to full force amplification for major tasks such as assembling large modules on-orbit or erecting habitats on planetary surfaces. Drawing from past SSL development of a robot-augmented EVA glove, conceptual designs and system requirements will be developed for RoboSuit, along with an overview of a logical research program to support its development.
It is anticipated that the RoboSuit approach, moving beyond evolutionary advances in current EVA technologies, will enable a dramatic increase in space operational capabilities, positively affecting long-range NASA goals such as space science and the human exploration and development of space.