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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 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.

The fit of a spacesuit has been identified as a crucial factor that will determine its usability. Therefore, because one-size-fits-all spacesuits seldom fit any wearer well, and because individually tailored spacesuits are costly, the University of Maryland has conducted research into a resizable Extravehicular Activity (EVA) suit. This resizing is accomplished through a series of cable-driven parallel manipulators, which are used to adjust the distance between plates and rings built into a soft space suit. These actuators, as well as enabling passive suit resizing, could be used to actively assist the astronaut's motion, decreasing the torques that must be applied for movement in a pressurized suit. This paper details the development and testing of an arm prototype, which is used to better understand the dynamics of a more complex torso-limb 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.

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.

This paper describes a unique concept for donning and doffing a spacesuit from a pressurized rover or habitat, which merges three independent concepts: suitports, neck-entry EVA suits, and the Morphing Upper Torso. The union of these concepts creates a novel and exciting suit and suitport system architecture, with many potential benefits over traditional suitport systems. To develop this concept, a neck-entry Morphing Upper Torso experimental model has been designed and fabricated, and systems level design studies have been performed, including visualization with the aid of CAD models of the neck-entry suitport on a small pressurized rover and a lunar habitat. As well, a donning test-station has been developed and used for experiments in 1-G, simulated microgravity and simulated partial gravity.

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.

The Ranger Telerobotic Shuttle Experiment (RTSX) is a Space Shuttle-based flight experiment to demonstrate key telerobotic technologies for servicing assets in Earth orbit. The flight system will be teleoperated from onboard the Space Shuttle and from a ground control station at the NASA Johnson Space Center. The robot, along with supporting equipment and task elements, will be located in the Shuttle payload bay. A number of relevant servicing operations will be performed-including extravehicular activity (EVA) worksite setup, orbital replaceable unit (ORU) exchange, and other dexterous tasks. The program is underway toward an anticipated launch date in CY2002. This paper gives an overview of the RTSX mission, and describes several follow-on mission scenarios involving cooperative Ranger and EVA activities.

Conventional ratcheting tools do not work efficiently in confined spaces and they have other limitations when used in space during extravehicular activity (EVA). The National Aeronautics and Space Administration’s (NASA) Goddard Space Flight Center has developed a three-dimensional (3-D) sprag/roller technology that has many benefits over the ratchet mechanism. The Space Systems Laboratory at the University of Maryland is using this technology in the development of EVA tools. The research discussed here describes the testing of an EVA roller wrench aboard NASA’s Reduced-Gravity Flying Laboratory (the KC-135), evaluation by astronauts in NASA/Johnson Space Center’s Neutral Buoyancy Laboratory, and the flight of a 3-D roller mechanism on Space Shuttle Mission STS-95.

The Maryland Advanced Research/Simulation (MARS) Suit is designed to be a low-cost test bed for extravehicular activity (EVA) research, providing an environment for the development and application of biomedical sensors and advanced EVA technologies. It is also designed to be used in gaining more experience with human-telerobotic interactions in an integrated EVA worksite. This paper details the first generation MARS Suit (MX-1) design, describes the low-cost development process, and presents results from ongoing suit testing, as well as plans for future work.