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NASA NTRSDate not supplied

NASA Advanced Space Suit Pressure Garment System Status and Development Priorities 2022

This paper discusses the current focus of NASA’s Advanced Space Suit Pressure Garment Technology Development team’s efforts, the status of that work, and a summary of longer-term technology development priorities and activities. For the past two years, the team has focused on the development and detailed design of the Extra-vehicular Mobility Unit (xEMU) to support two parallel missions: A 2023 deadline for delivery of the xEMU International Space Station (ISS)Demonstration configuration, and a planetary walking suit configuration to support landing on the Moon in 2024. The baselined design of the xEMU will be reviewed. The results of Design Verification Testing (DVT) will be presented and its ability to provide confidence in the hardware’s ability to meet flight requirements will be discussed. To the extent possible, an impact assessment of the Exploration Extravehicular Activity Services (xEVAS) Contract will be provided. Finally, a brief review of longer-term pressure garment challenges and technology gaps will be presented to provide an understanding of the advanced pressure garment team’s technology investment priorities and needs for future exploration missions.

xEMU↗

NASA NTRS1992

Tests of an alternate mobile transporter and extravehicular activity assembly procedure for the Space Station Freedom truss

Results are presented from a ground test program of an alternate mobile transporter (MT) concept and extravehicular activity (EVA) assembly procedure for the Space Station Freedom (SSF) truss keel. A three-bay orthogonal tetrahedral truss beam consisting of 44 2-in-diameter struts and 16 nodes was assembled repeatedly in neutral buoyancy by pairs of pressure-suited test subjects working from astronaut positioning devices (APD's) on the MT. The truss bays were cubic with edges 15 ft long. All the truss joint hardware was found to be EVA compatible. The average unit assembly time for a single pair of experienced test subjects was 27.6 sec/strut, which is about half the time derived from other SSF truss assembly tests. A concept for integration of utility trays during truss assembly is introduced and demonstrated in the assembly tests. The concept, which requires minimal EVA handling of the trays, is shown to have little impact on overall assembly time. The results of these tests indicate that by using an MT equipped with APD's, rapid EVA assembly of a space station-size truss structure can be expected.

Heard, Walter L., Jr.↗

NASA NTRS1967

Astronautics and Aeronautics, 1966

At the opening of the tenth year in the era of man’s mobility in outer space, we can look back on 1966 as offering convincing evidence that the United States had gained great competence. This evidence included: five orbital space flights by ten Gemini astronauts; four lunar missions undertaking the orbiting of and soft landing on the moon; numerous contributions to scientific knowledge by unmanned spacecraft and sounding rockets; and further demonstrations of the practical utility of operational space systems, including weather and communications satellites. During 1966, a record 100 American spacecraft were placed into earth orbit or on escape trajectories. Thousands of revealing and useful pictures of the earth were taken from space and of the moon from lunar orbit and on its surface. The Gemini program ended with rendezvous and docking experiments and extravehicular activity by the Gemini test pilots as the Apollo R&D test flights leading to the manned lunar mission came into the schedule. Thirty-five major scientific, technological, and operational milestones were cited for 1966 by the President in his Report to the Congress on aeronautical and space activities of the United States. This was one measure of the American commitment to share in the peaceful exploration of space for all mankind. Another was our support of the final steps toward a United Nations space treaty, undertaken to ensure that the peaceful exploitation of space had juridical basis in international law. Spectacular as some events in the space venture were in 1966, they nonetheless came to have diminished novelty in the eyes of many laymen. The multitude of both important and unspectacular space activities attained almost an accepted and routine place. This volume, as well as its predecessor chronicles, offers a ready reference on the major as well as the less-well known events. Beyond the welter of documented details on the complex nature of aeronautical and space related events and their impact, this volume helps to provide a better perspective upon today as we contemplate tomorrow. Such intent also serves future historians and analysts who cannot be unmindful of what is herein presented. When the Congress created the National Aeronautics and Space Administration in 1958, it charged NASA with the responsibility to “contribute materially to . . . the expansion of human knowledge of phenomena in the atmosphere and space’’ and to “provide for the widest practical and appropriate dissemination of information concerning its activities and results thereof.” NASA has attempted to do this and to include documentation for the historical record. The relating of NASA history begins with this day-by day chronicle and leads to more specialized studies and histories of the unprecedented task of extending man’s mobility and understanding beyond his planet. While a chronology cannot in itself serve as a full-fledged history, the size of this annual volume alone is illustrative of the scope and complexity of the historical task yet to be completed as memories fade and the records disappear.

SPACE PROBE↗

NASA NTRSDate not supplied

Development of an Inertial Sensor-based Methodology for Spacesuited Geology Task Assessments during Simulated Lunar Extravehicular Activities

Lunar surface exploration during Artemis missions will require the specific skill set of geology sampling. Apollo astronauts had extensive training and used specialized tools to collect lunar rocks, core samples, pebbles, sand, and dust. The inflexibility of the pressurized Apollo spacesuits forced sampling to be taken at a standstill posture. However, new exploration spacesuits are expected to incorporate advanced materials and joint bearings, allowing for greater mobility and a wider range of functional postures. Thus, science and exploration during Artemis missions will likely involve a variety of standing, squatting, and kneeling postures. In preparation for future lunar exploration missions, NASA provides geologic training to astronauts and other mission personnel. This professional training with a spacesuit in simulated lunar environments will enhance performance and reduce risk of injury to astronauts on the lunar surface. However, anecdotally, untrained or newly trained people wearing prototype planetary spacesuits have been observed to performing motions differently than a trained geologist would when conducting the same geology sampling tasks. Therefore, a tool for evaluating geology postures at extravehicular activity (EVA) training facilities becomes required. In this paper, we introduce a novel inertial measurement unit (IMU)-based method of geology task assessments in spacesuited conditions during simulated lunar EVAs. As a case study, two subjects (one geologist and one non-geologist) participated and donned the Mark III prototype planetary spacesuit during offloading with the spreader bar gimbal in NASA’s Active Response Gravity Offload System (ARGOS). For automated geology task assessments, the spacesuit was instrumented with three wireless IMUs (APDM Opal, OR, USA): one on the chest and one each on the left and right ankle bearings. Then subjects performed geology tasks using various tools (rake, trench, hammer chisel, scoop, and drive tube) for 45 minutes each. The chest IMU measured the torso tilt angle in the sagittal plane. We used an ensemble learning method with the ankle IMUs to discriminate between standing and kneeling activities. IMU data were processed using custom MATLAB (Mathworks, MA, USA) software. In our case study, the developed method was able to discriminate differences in standing and kneeling activity levels between subjects who were all highly experienced with spacesuited testing. Our preliminary data showed one subject maintained the constant and lower range of the upper body tilt angle while both standing and kneeling, while the other subject showed more variation of the upper body tilt angle and preferred bending the upper body rather than changing from standing to kneeling posture and vice versa. While geology experience may be a factor, these results need further investigation as suit sizing and ARGOS offloading configurations have been proven to have a significant influence on suited ARGOS tasks. Also, more subjects will be needed to complete these tasks for validation. IMU-based geology task assessments can provide useful information for geology training programs. Additionally, our IMU-based posture analysis can provide new insights into how to evaluate spacesuited geology task characteristics of astronauts during simulated lunar EVAs.

Kyoung Jae Kim↗

NASA NTRS2004

Exploration EVA System

In January 2004, the President announced a new Vision for Space Exploration. NASA's Office of Exploration Systems has identified Extravehicular Activity (EVA) as a critical capability for supporting the Vision for Space Exploration. EVA is required for all phases of the Vision, both in-space and planetary. Supporting the human outside the protective environment of the vehicle or habitat and allow ing him/her to perform efficient and effective work requires an integrated EVA "System of systems." The EVA System includes EVA suits, airlocks, tools and mobility aids, and human rovers. At the core of the EVA System is the highly technical EVA suit, which is comprised mainly of a life support system and a pressure/environmental protection garment. The EVA suit, in essence, is a miniature spacecraft, which combines together many different sub-systems such as life support, power, communications, avionics, robotics, pressure systems and thermal systems, into a single autonomous unit. Development of a new EVA suit requires technology advancements similar to those required in the development of a new space vehicle. A majority of the technologies necessary to develop advanced EVA systems are currently at a low Technology Readiness Level of 1-3. This is particularly true for the long-pole technologies of the life support system.

Kearney, Lara↗

NASA NTRSDate not supplied

Toward an IMU-Based Space Suit Motion Capture System

Spacesuits are complex engineering systems that sustain human health and enable performance outside Earth-like environments. These systems must support human mobility and physical workload demands while minimizing injury risk during extravehicular activity (EVA). Future EVA operations on the Lunar surface are expected to be more frequent and require higher physical workloads than previously during the ISS, Shuttle, and Apollo programs. To characterize the workloads and ergonomics needs a suit must support, the kinematics of the space suit must be measured during operationally-relevant tasks in ground analog environments. Kinematics capture of the suit is challenging for traditional optical motion capture (OMC) approaches due to marker occlusion, harsh lighting or environmental conditions, and tests with suit surrogates in outdoor field environments. To this end, engineers at NASA are developing the Augmented Suit Inverse Kinematics (ASIK) system, a complete motion capture method and inverse kinematics solver which relies solely on a network of wireless inertial measurement units (IMUs) attached to the major kinematic segments of the spacesuit. The ASIK modeling language allows for the simple inclusion of probabilistic priors such as suit size and shape or IMU poses. The ASIK system was tested in a 7-subject pilot study. Each subject donned NASA’s new prototype exploration spacesuit in the Active Response Gravity Offload System (ARGOS) facility at Johnson Space Center in Houston, TX. The suits were outfitted with 12 IMUs to estimate lower body and trunk kinematics. The suits were also outfitted with a set of reflective OMC markers, and traditional OMC data was collected and processed. Characterization of the ASIK-derived suit joint angles’ accuracy against an optical motion capture datum will be presented. Discussion of these results, as well as discussion of system calibration and nuances of mathematical observability, will be included.

IMU↗

NASA NTRSDate not supplied

Toward an IMU-based Space Suit Motion Capture System

Spacesuits are complex engineering systems that sustain human health and enable performance outside of Earth-like environments. These systems must support human mobility and physical workload demands while minimizing injury risk during extravehicular activity (EVA). Future EVA on the lunar surface during the Artemis program is expected to be more frequent and require higher physical workloads than previous EVAs during the ISS, Shuttle, or Apollo programs. Hence it is important to optimize future as well as current spacesuits to be efficient and comfortable for the success of space and planetary missions. To enable this, an efficient method is needed to test these spacesuits on the ground.When testing spacesuits in ground environments, it is often necessary to understand the kinematics of the suit to validate the design against relevant requirements or characterize the physical workload necessary to operate the suit. This is a challenging task for traditional optical motion capture (OMC) approaches: suit-mounted OMC markers are easily occluded by the subject or environment and may become detached during testing. Controlling lighting and reflectivity of objects in the motion capture volume is also difficult. Fixed-position OMC cameras also constrain testing to a small and contrived laboratory environment, disallowing kinematics capture in field environments.One promising alternative is the use of suit-mounted inertial measurement units (IMUs). These sensors are small, unobtrusive, and portable, but come at the cost of increased sensor noise and complexity of the software and mathematics to analyze the collected data. To this end, engineers at NASA are developing the Augmented Suit Inverse Kinematics (ASIK) system, a complete motion capture methodand inverse kinematics solver which relies solely on a network of wireless IMUs attached to the major kinematic segments of the spacesuit. The ASIK modeling language allows for the simple inclusion of probabilistic priors such as suit size and shape or IMU positions and rotations. Furthermore, to increase accuracy and reduce operational overhead to use this motion capture approach, the developed inverse kinematics solver exploits so-called self-calibratingalgorithmic techniques, which reduce the need for precise alignment of the sensors on the segments or scripted functional calibration procedures. The ASIK system was tested in a 7-subject pilot study. Each subject donned NASA’s new prototype exploration spacesuit in the Active Response Gravity Offload System (ARGOS) facility at the NASA Johnson Space Center. The subjects were outfitted with a set of 14 APDM (Portland, OR, USA) Opal IMUs, 12 of which were used in the ASIK model to estimate lower body and trunk kinematics. The subjects were also outfitted with a set of reflective OMC markers and traditional OMC data was collected and processed. Presented results will include characterization of ASIK-derived suit joint angles accuracy against an optical motion capture datum. Discussion of these results, as well as discussion of system calibration and nuances of mathematical observability, will be included.If successful, IMU-based motion capture will enable testing and validation of spacesuits more frequently, with less overhead, in more extreme environments. Future work will apply these techniques to common spacesuit testing tasks, such as gait, mobility, and balance assessment, physical workload characterization, and ergonomics evaluations.

Timothy Mcgrath↗

NASA NTRS2012

Benefits of a Single-Person Spacecraft for Weightless Operations

Historically, less than 20 percent of crew time related to extravehicular activity (EVA) is spent on productive external work.1 A single-person spacecraft with 90 percent efficiency provides productive new capabilities for maintaining the International Space Station (ISS), exploring asteroids, and servicing telescopes or satellites. With suits, going outside to inspect, service or repair a spacecraft is time-consuming, requiring pre-breathe time, donning a fitted space suit, and pumping down an airlock. For ISS, this is between 12.5 and 16 hours for each EVA, not including translation and work-site set up. The work is physically demanding requiring a day of rest between EVAs and often results in suit-induced trauma with frequent injury to astronauts fingers2. For maximum mobility, suits use a low pressure, pure oxygen atmosphere. This represents a fire hazard and requires pre-breathing to reduce the risk of decompression sickness (bends). With virtually no gravity, humans exploring asteroids cannot use legs for walking. The Manned Maneuvering Unit offers a propulsive alternative however it is no longer in NASA s flight inventory. FlexCraft is a single person spacecraft operating at the same cabin atmosphere as its host so there is no risk of the bends and no pre-breathing. This allows rapid, any-time access to space for repeated short or long EVAs by different astronauts. Integrated propulsion eliminates hand-over-hand translation or having another crew member operate the robotic arm. The one-size-fits-all FlexCraft interior eliminates the suit part inventory and crew time required to fit all astronauts. With a shirtsleeve cockpit, conventional displays and controls are used and because the work is not strenuous no rest days are required. Furthermore, there is no need for hand tools because manipulators are equipped with force multiplying end-effectors that can deliver the precise torque for the job.

Griffin, Brand N.↗

NASA NTRS2004

Results from an Investigation into Extra-Vehicular Activity (EVA) Training Related Shoulder Injuries

The number and complexity of extravehicular activities (EVAs) required for the completion and maintenance of the International Space Station (ISS) is unprecedented. The training required to successfully complete this magnitude of space walks presents a real risk of overuse musculoskeletal injuries to the EVA crew population. There was mounting evidence raised by crewmembers, trainers, and physicians at the Johnson Space Center (JSC) between 1999 and 2002 that suggested a link between training in the Neutral - Buoyancy Lab (NBL) and the several reported cases of shoulder injuries. The short- and long-term health consequences of shoulder injury to astronauts in training as well as the potential mission impact associated with surgical intervention to assigned EVA crew point to this as a critical problem that must be mitigated. Thus, a multi-directorate tiger team was formed in December of 2002 led by the EVA Office and Astronaut Office at the JSC. The primary objectives of this Tiger Team were to evaluate the prevalence of these injuries and substantiate the relationship to training in the NBL with the crew person operating in the EVA Mobility Unit (EMU). Between December 2002 and June of 2003 the team collected data, surveyed crewmembers, consulted with a variety of physicians, and performed tests. The results of this effort were combined with the vast knowledge and experience of the Tiger Team members to formulate several findings and over fifty recommendations. This paper summarizes those findings and recommendations as well as the process by which these were determined. The Tiger Team concluded that training in the NBL was directly linked to several major and minor shoulder injuries that had occurred. With the assistance of JSC flight surgeons, outside consultants, and the lead crewmember/physician on the team, the mechanisms of injury were determined. These mechanisms were then linked to specific aspects of the hardware design, operational techniques, and the training environment. During the 1999 to 2003 time frame many variables converged to make it impossible to determine with any accuracy which one or two root causes were primarily involved. Therefore a broad range of recommendations was established to prevent future injury to crewmembers training in the NBL in the near term. Many of these recommendations are lessons learned that are essentially timeless and therefore should be passed on to future EVA endeavors to ensure that hardware designs and operational techniques utilized in the future consider the demands of training on the human body here on earth.

Johnson, Brian J.↗

NASA NTRS2020

The Flexible Lunar Architecture for Exploration (FLARE): Designed for the Artemis-3 Moon 2024 Mission and Beyond

The Flexible Lunar Architecture for Exploration (FLARE) is a concept to deliver four crew to the lunar surface for 7 to 14 days and then return them safely to Earth by 2024. This meets NASA’s internal 2024 lunar landing deadline directed by President Trump (Trump, 2017) and the “5-year” goal set forth by Vice President Pence (Pence, 2019). FLARE is an alternative to NASA’s Human Landing System reference architecture from the Design Analysis Cycle (DAC) #2 (NASA, 2019b). The minimum FLARE concept uses one Space Launch System launch, one Orion, one European Service Module (ESM), and one human lander to deliver four crew to the Moon for a minimum surface duration of 7 days and return them to Earth. FLARE adds a new capability, called the SpaceTug, based upon the mature and successful United Launch Alliance “Common” Centaur Upper Stage vehicle, with modifications. In FLARE, the SpaceTug provides propulsion needed to return the Orion+ESM from the Moon to Earth. The SpaceTug also provides propulsion to deliver the human lander Descent Element (DE) and Ascent Element (AE) separately to lunar orbit. The Orion+ESM then completes a rendezvous with the mated DE+AE in lunar orbit. FLARE also offers optional phases to the Moon 2024 mission. The SpaceTug can also deliver components of the planned Gateway - including the Power and Propulsion Element and the Habitation and Logistics Outpost - to lunar orbit; however, the planned FLARE destination is a Low Lunar Frozen Polar Orbit unlike the NASA DAC2 plan for a Near Rectilinear Halo Orbit. FLARE also provides an option to deliver precursor equipment - including a habitation module, crew mobility devices and an In-Situ Resource Utilization demonstration - to the lunar surface for enhanced crew exploration and science with the extended 14-day surface mission.

Commercial Launch Vehicles (CLV)↗

NASA NTRS2011

Development and Deployment of Robonaut 2 to the International Space Station

The development of the Robonaut 2 (R2) system was a joint endeavor with NASA and General Motors, producing robots strong enough to do work, yet safe enough to be trusted to work near humans. To date two R2 units have been produced, designated as R2A and R2B. This follows more than a decade of work on the Robonaut 1 units that produced advances in dexterity, tele-presence, remote supervision across time delay, combining mobility with manipulation, human-robot interaction, force control and autonomous grasping. Design challenges for the R2 included higher speed, smaller packaging, more dexterous fingers, more sensitive perception, soft drivetrain design, and the overall implementation of a system software approach for human safety, At the time of this writing the R2B unit was poised for launch to the International Space Station (ISS) aboard STS-133. R2 will be the first humanoid robot in space, and is arguably the most sophisticated robot in the world, bringing NASA into the 21st century as the world's leader in this field. Joining the other robots already on ISS, the station is now an exciting lab for robot experiments and utilization. A particular challenge for this project has been the design and certification of the robot and its software for work near humans. The 3 layer software systems will be described, and the path to ISS certification will be reviewed. R2 will go through a series of ISS checkout tests during 2011. A taskboard was shipped with the robot that will be used to compare R2B's dexterous manipulation in zero gravity with the ground robot s ability to handle similar objects in Earth s gravity. R2's taskboard has panels with increasingly difficult tasks, starting with switches, progressing to connectors and eventually handling softgoods. The taskboard is modular, and new interfaces and experiments will be built up using equipment already on ISS. Since the objective is to test R2 performing tasks with human interfaces, hardware abounds on ISS and the crew will be involved to help select tasks that are dull, dirty or dangerous. Future plans for R2 include a series of upgrades, evolving from static IVA (Intravehicular Activity) operations, to mobile IVA, then EVA (Extravehicular Activity).

Ambrose, Robert O.↗

NASA NTRSDate not supplied

Developing a Motion-Based System for Lunar Vehicle Handling Qualities Testing

— Motion and visual cue influences are critical in any simulator system, as they impact multiple aspects of the human’s neurovestibular and visual systems. Cues of real motion proceeds to the brain before cues of visual change. It is important therefore for simulator motion cues to exist and to match those realistically with those of the real vehicle to provide transferable training of the activity for operations. The United Kingdom’s Royal Air Force Institute of Aviation Medicine (1989)[1] stated that motion platforms are the only simulation devices capable of fully stimulating the body motion sensors. They confirmed that motion platforms can impart accelerations to the whole body and therefore exercise the automatic motion feedback-loop that operators are used to. With both visual and motion cues handling the vehicle becomes more realistic. Strachan (2019)[1] confirms motion cueing from a well set-up motion platform has been found to be important especially in conditions such as night or reduced visibility where motion cues may be more relied upon. As of this writing, the only lunar rover motion simulator is housed at the General Motors (GM) Milford Proving Ground, which only simulates the motions of a traditional car. A NASA Test Team proposed to complete a motion-based simulation system for NASA’s Lunar Terrain Vehicle (LTV) which resides at Johnson Space Center’s Systems Engineering Simulator facility. This activity integrated existing fixed base simulation capabilities with a newly procured six-degree of freedom motion base platform for the design, development, evaluation, and training associated with the LTV project. This would incorporate a South Pole Lunar virtual reality simulation using Lunar Reconnaissance Orbiter 5m/pixel high-resolution imagery and Unreal 5.2 Virtual Shadow Maps, combined with a virtual reality (VR) headset, integrated within a rover cockpit on a Mikrolar Motion Platform for evaluating human performance and vehicle handling qualities for concept roving vehicle designs. The motion-based system received its Human Rating Certification on March 2023. To begin testing the new facility, a preliminary handling qualities study was conducted. The objectives were to determine if there is a correlation amongst three handling quality methods of performance for a lunar vehicle and to understand the effects of a simulated 1/6-g loads and visuals with a motion platform on the operator while in a 1-g physical environment. The capability this system provides directly benefits the NASA’s Extravehicular Activity and Human Surface Mobility Program and NASA’s Flight Operations Directorate in evaluating the driving qualities of vehicle concepts, human performance related to the operating of a lunar surface vehicle, and assessment of suit related driving impacts. It would also provide direct operational benefit by providing a first-in class and unique simulation platform for the lunar astronaut training curriculum. The empirical knowledge of rover and human performance on this scale is paramount as there is currently no other lunar surface simulator with these capabilities. The result of this study ensures a broadly applicable method of testing for shirtsleeve, unpressurized and pressurized suited rover handling qualities.

Test Track↗