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This paper summarizes the activities of the University of Maryland Space Systems Laboratory in performing a design study for a minimum functionality lunar habitat element for NASA's Exploration Systems Mission Directorate. By creating and deploying a survey to personnel experienced in Earth analogues, primarily shipboard and Antarctic habitats, a list of critical habitat functions was established, along with their relative importance and their impact on systems design/implementation. Based on a review of relevant past literature and the survey results, four habitat concepts were developed, focused on interior space layout and preliminary systems sizing. Those concepts were then evaluated for habitability through virtual reality (VR) techniques and merged into a single design. Trade studies were conducted on habitat systems, and the final design was synthesized based on all of the results.

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.

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.

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.

The University of Maryland Space Systems Laboratory has developed a system that replicates some limited aspects of pressure suits to facilitate neutral buoyancy research into EVA bioinstrumentation, advanced EVA training, and EVA/robotic interactions. After a two year upgrade from its MX-1 predecessor, the MX-2 space suit analogue is currently undergoing a variety of system integration tests in preparation for initial operational testing, leading to routine use for EVA simulation and as a testbed for advanced space suit technology. The MX-2 is built around a hard upper torso with integrated hemispherical helmet and rear-entry hatch. Three-layer soft-goods are used for the arms and lower torso, while an open loop air system regulates suit pressure to 3 psid. Wrist disconnects allow the use of standard EMU or Orlan gloves, or experimental gloves such as the mechanical counterpressure gloves and power-assisted gloves developed previously by the SSL.

Neutral buoyancy (NB) and parabolic flight (PF) are the only available human-scale three-dimensional spaceflight simulation environments. As such, both environments are used extensively for both research and mission operations purposes despite a lack of quantitative (or even qualitative) characterization of the fidelity of either environment to the spacelfight analog. The present study was undertaken as part of a larger research effort to begin to build such characterizations. Eight healthy adults (4 men and 4 women) were asked to adopt relaxed postures while ‘standing’ in space shuttle middeck standard-type foot restraints, in NB and during the 0g periods of PF. Subjects were tested in NB in 9 orientations, 3 trials each: Upright; tilted 45° Front, 45° Back, 45° Right, 45° Left; and tilted 90° Front, Back, Right, and Left. PF limitations prohibited 90° testing; consequently the PF test protocol included only Upright and 45° orientations.

With NASA's resources dedicated to the six-fold increase in extravehicular operations required for the construction of International Space Station, there are few or no opportunities to conduct neutral buoyancy research which requires the use of pressure suits. For this reason, the University of Maryland Space Systems Laboratory has developed a system which replicates some limited aspects of pressure suits to facilitate neutral buoyancy research into EVA bioinstrumentation and EVA/robotic interactions. The MX-2 suit analogue is built around a hard upper torso with integrated hemispherical helmet and rear-entry hatch. Three-layer soft goods (pressure bladder, restraint layer, and thermal/micrometeoroid garment with integral ballast system) are used for the arms and lower torso.

Neutral buoyancy (NB) and parabolic flight (PF) are the only presently available human-scale three-dimensional spaceflight simulation environments, and as such, both NB and PF are used extensively to simulate spaceflight conditions for both research and mission operations purposes. However, there is little or no quantitative (or even qualitative) material in the literature to characterize the fidelity of either environment to its analog. The present study was undertaken as part of a larger research effort to begin to build such characterizations. Eight healthy adults (4 men and 4 women) were asked to adopt relaxed postures while “standing” in space shuttle middeck standard-type foot restraints, in NB and during the 0g periods of PF. Subjects were tested in NB in 9 orientations, 3 trials each: Upright; tilted 45° Front, 45° Back, 45° Right, 45° Left; tilted 90° Front, 90° Back, 90° Right, and 90° Left.

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.

Since the earliest days of manned space flight, robotics and human activities have tended to view each other as the competition. Although the International Space Station lists robotic servicing as an alternative to extravehicular activity (EVA) operations, there has been little consideration of significant cooperation between humans and telerobots in the same work site. This paper proposes the establishment of a list of potential interaction levels between humans and robots in the extravehicular work site: Robotic assistant Robotic associate Robotic surrogate Robotic specialist Human/robotic symbiosis The first three categories deal with increasing levels of robotic capability to perform EVA tasks, particularly with EVA interfaces. “Specialist” activities refer to specific task assignments that are singularly associated with humans or robots, such as an Astronaut Support Vehicle or a Telerobotic Rescue System for EVA.

In the present study, 8 experienced neutral buoyancy test divers were instructed to maintain quiet relaxed posture while ‘standing’ in instrumented space shuttle middeck (IVA) type foot restraints in the Space Systems Laboratory (SSL) Neutral Buoyancy Research Facility (NB) and onboard the NASA KC-135 reduced gravity aircraft (PF). Foot restraint reaction loads and subject joint angles were recorded during blind and sighted conditions. Visual cues played a significant role in subject anxiety onboard the KC; however, while subject joint angles and reaction loads differed between NB and PF conditions, no differences were found between sighted and blind conditions in either simulation environment for reaction loads or joint angles. This very surprising result indicates that there are not only anecdotal but concrete differences between reduced gravity and terrestrial posture mechanisms.

The Ranger Telerobotic Flight Experiment is a highly complex teleoperated spacecraft, requiring direct human control of 36 major degrees of freedom. The University of Maryland Space Systems Laboratory and the NASA Ames Research Center are cooperating on the development of a virtual reality control station to streamline human interfaces with the Ranger spacecraft. This describes the design and integration of the Ranger Command Chair, a system incorporating fully immersive helmet-mounted stereo displays with head tracking, hand tracking for direct positional control, and supplemental controls and displays to allow a single operator to functionally control the entire vehicle. This system is currently undergoing tests with the Ranger Neutral Buoyancy Vehicle, a functionally identical vehicle used for systems development and flight operations simulations.