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Real time knowledge of the metabolic workload of an astronaut during an Extra-Vehicular Activity (EVA) can be instrumental for space suit research, design, and operation. Three indirect calorimetry approaches were developed to determine the metabolic workload of a subject in an open-loop space suit analogue. A study was conducted to compare the data obtained from three sensors: oxygen, carbon dioxide, and heart rate. Subjects performed treadmill exercise in an enclosed helmet assembly, which simulated the contained environment of a space suit while retaining arm and leg mobility. These results were validated against a standard system used by exercise physiologists. The carbon dioxide sensor method was shown to be the most reliable and a calibrated version of it will be integrated into the MX-2 neutral buoyancy space suit analogue.

The research discussed in this paper demonstrates further advancements in the concept of a Morphing Upper Torso, which incorporates robotic elements within the pressure suit design to enable a resizable, highly mobile and easy to donn/doff spacesuit. A full scale experimental model has been made, which accompanies several analytical models. The Jacobian matrix for the robotic system, which multiplies the total twist vector of the system to yield the vector of actuator velocities, is derived. This dynamic analysis enables quantification of the dynamic actuator requirements, given demanded trajectories of the rings. A motion capture pilot study was done to develop a methodology to obtain measurements of suit movement and hence the ring trajectories. Subjects performed various tasks that a suited astronaut may perform on a planetary surface, while wearing a torso mockup within the motion capture system.

There has recently been an increasing focus on humans working cooperatively with robotic systems in space exploration and operations. Considerable work has been performed on distributed architectures to enable such interaction. The research described here looks at the human-robot interaction from the EVA astronaut's perspective, describing a first generation human-machine interface implemented and tested on an existing experimental spacesuit analog, the MX-2. The ultimate goal is to enable EVA astronauts to operate more independently of remote operators and work effectively with autonomous and teleoperated robots. The current system integrates speech interaction and visual interfaces as a first step towards this goal.

Extensive prior research at the University of Maryland Space Systems Laboratory has identified significant operational advantages to high levels of integration between EVA crew and dexterous robotics. Crew performance on recent Hubble Space Telescope repair missions was broken down into task primitives, and evaluated for the impact of dexterous robotics in direct support of extravehicular activity. Results demonstrate that direct EVA-robotic cooperation can increase human performance in satellite servicing tasks by factors ranging from at least 60% (for highly complex and dexterous servicing tasks) to as much as 400% for more simple activities with greater levels of planned orbital replacement unit (ORU) interchange. This paper details experimental and analytical investigations of differing approaches to adding dexterous robotic capabilities to the EVA work site, via increasingly direct integration of robotics into the space suit system itself.

The next generation of pressure suits must enable large-scale planetary Extra-Vehicular Activities (EVA). Astronauts exploring the moon and Mars will be required to walk many kilometers, carry large loads, perform intricate experiments, and extract geological samples. Advanced pressure suit architectures must be developed to allow astronauts to perform these and other tasks simply and effectively. The research developed here demonstrates integration of robotics technology into pressure suit design. The concept of a robotically augmented pressure suit for planetary exploration has been developed through the use of analytical and experimental investigations. Two unique torso configurations are examined, including a Soft/Hard Upper Torso with individually adjustable bearings, as well as advances in Morphing Upper Torso research, in which an all-soft torso is analyzed as a system of interconnected parallel manipulators.

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.

Employing a cooperative human and robotic team has the potential to greatly reduce human workload during space missions and create more efficient operational teams. The Hubble Space Telescope Servicing Mission 3A tasks were assessed and modeled with three different human and robot team pairings to elucidate the difference to team performance. Tasks were allocated to the standard two-human EVA crew and a robotic agent for each of the cases. The schedules reduce the human crew's involvement time in each EVA day's activities by rearranging subtasks to minimize the human crew's wait time. This work examines three agent participation scenarios and their effect on the expected efficiency of the cooperative team during mission activities.

The University of Maryland has performed a detailed design for the space equivalent of an atmospheric diving suit. The Space Construction and Orbital Utility Transport (SCOUT) is a small single-person spacecraft, with all necessary utilities for extended sorties away from the host station. Through a pair of AX-5 style space suit arms integrated into the cabin wall, as well as a trio of dexterous manipulators, the SCOUT operator can directly interact with the work site environment, performing spacecraft servicing, structural assembly, or other tasks traditionally done by an astronaut in a space suit. Originally designed as an augmentation to the NASA Gateway station architecture for the Earth-Moon L1 system, studies indicate that a SCOUT-type EVA system would represent a substantial benefit to International Space Station operations as well.

A fully operational space suit analogue for use in a neutral buoyancy environment has been developed and tested by the University of Maryland’s Space Systems Laboratory. Repeated manned operations in the Neutral Buoyancy Research Facility have shown the MX-2 suit analogue to be a realistic simulation of operational EVA pressure suits. The suit is routinely used for EVA simulation, providing reasonable joint restrictions, work envelopes, and visual and audio environments comparable to those of current EVA suits. Improved gloves and boots, communications carrier assembly, in-suit drink bag and harness system have furthered the semblance to EVA. Advanced resizing and ballasting systems have enabled subjects ranging in height from 5′8″ to 6′3″ and within a range of 120 lbs to obtain experience in the suit. Furthermore, integral suit instrumentation facilitates monitoring and collection of critical data on both the suit and the subject.

Future space missions will involve humans and robots cooperatively performing operational tasks in various team combinations. Part of the required preparation for such missions includes understanding the issues involved in task allocation between disparate agents, and efficiently ordering tasks within the mission constraints. The scheduling tool developed in this research distributes pre-allocated task primitives between a cooperative human crew and dexterous robotic team. It combines real-world precedent constraints with algorithms from scheduling theory to reorder and tighten each crew member's individual schedule. The schedules minimize astronaut involvement time by stacking astronaut-performed tasks together in the schedule. This also minimizes astronaut workload in the completion of each task. Hubble Space Telescope Servicing Mission 3A was used as an example to test the allocation and scheduling tool.