Results for “EVA” — Page 31

NASA NTRSDate not supplied

Evaluation of Aerobic Capacity in Relation to Simulated Lunar Surface Extravehicular Activities

INTRODUCTION Astronauts will need to be physically prepared to successfully execute strenuous Extravehicular Activities (EVA)on the Lunar surface. Compared to Apollo missions, Artemis missions will include EVAs of increased physical demand, frequency, and duration, thus requiring adequate fitness to successfully and safely complete mission objectives and potential contingency scenarios. Currently, aerobic fitness standards for partial gravity (g)surface EVAs are not well supported by high-fidelity EVA analog data. This investigation aims to characterize metabolic demands from Lunar analog EVA simulations in relation to the current NASA standards for celestial partial-g aerobic fitness(aerobic capacity (VO2pk) ≥36.5ml/kg/min). METHODS To evaluate current Lunar EVA aerobic fitness requirements, a pilot study was performed to characterize metabolic ratesduring6 hour simulated EVAs. The EVAs were performed in pressurized MKIII (n=2male) and xEMU (n=3 female) spacesuits offloaded to 1/6 g in the NASA Active Response Gravity Offload System. VO2pk was assessed via graded exercise testing on acycle ergometer and physical workload was quantified as percent ofVO2pk. RESULTS Four out of five subjects did not meet the current NASA celestial surface EVA aerobic standard (3 xEMU, 1MKIII;35.1±0.9 ml/kg/min). During simulated EVAs, subjects (xEMU: 35±1ml/kg/min; MKIII: 44±10ml/kg/min) worked at an average 36%VO2pk(xEMU) and 31% VO2pk(MKIII). For xEMU subjects, the tasks with the greatest average metabolic rates were 2km treadmill traverse(0% grade: 47.2%VO2pk[max 69.1%]), object relocation (45.2%VO2pk[max 60.5%]), and 1.5km traverse (0% grade: 45%VO2pk[max 59.7%]). For MKIII subjects, the tasks with the greatest average metabolic rates were 0.5km treadmill traverse (30% grade: 35.4% VO2pk[max 45.5%]), object relocation(31% VO2pk[max 40.8%]), and treadmill traverse (0% grade: 29.9%VO2pk[max 45.9%]). CONCLUSIONS While average metabolic rates for simulated Lunar EVA fall within sustainable work ranges of30–40% VO2pkand life support system limitations, task-specific metabolic rates exceed this range and may indicate that greater fitness is necessary for more strenuous tasks expected to be performed on the Lunar surface. As few subjects met the standard, more data is needed to adequately evaluate the NASA 3001 standard.

N C Strock↗

NASA NTRS2024

Considerations for Health and Performance during Surface Extravehicular Activities

BACKGROUND: NASA’s objectives for expanding human presence beyond low Earth orbit will require Extravehicular Activities (EVAs) on lunar and planetary surfaces. Given the physiological and functional demands of conducting surface EVAs in a pressurized spacesuit in reduced gravity environments, there is a possibility that crew injury and compromised physiological and/or functional performance may present. OVERVIEW: Many human health and performance knowledge gaps exist in regards to exploration EVA that require characterization to ensure safety, reliability, and mission success. To address knowledge gaps, EVA simulations in Earth-based analog environments and/or spacesuit simulators can be utilized to provide valuable insights into task-based physiologic and metabolic costs, cognitive loads, and associated operational limitations to inform future mission concepts. Physical workloads approaching 60% of maximum metabolic rates and 85% age-predicted heart rate maxima; core body temperatures approaching 100° F; and subjective responses indicating limited spare cognitive capacity via Bedford scale have been observed during ground-based exploration EVA simulations in the NASA Active Response Gravity Offload Simulator (ARGOS) and Neutral Buoyancy Lab (NBL) during simulated planetary EVAs in pressurized suits. Further, ground-based EVA analogs vary in their ability to simulate planetary EVA and resulting physical workloads. DISCUSSION: Metabolic costs, thermal burdens, functional strength, and cognitive impacts have been and must continue to be assessed in ground-based analogs to fully characterize operational demands and crew readiness levels for exploration EVA. Considerations should be given to enabling a new concept of high-tempo surface EVA operations and associated work-rest intervals, understanding human health and performance impacts of evolving commercial suit designs and capabilities, and predictive modeling and decision support capabilities to enable safe and successful EVA operations.

P Estep↗

NASA NTRSDate not supplied

Assessing the Influence of Decompression Sickness on Medical Risk for Artemis

As NASA begins to shift its focus from LEO missions to the Moon and beyond, our understanding of the risk associated with human spaceflight is challenged by mission profiles and objectives far different from preceding missions. For Artemis, one of these aspects is surface Extra Vehicular Activity (EVA) tempo, in which the crew will perform 3 to 4 surface EVA’s in quick succession. The crew health and performance risk associated with EVA Decompression Sickness (DCS) and its associated countermeasures, is an important consideration for Artemis missions given this new and unprecedented EVA frequency. Successfully completing Artemis mission objectives relies heavily on the crew being able to perform and complete these EVAs. This analysis quantifies how medical risk changes when accounting for the expected increase in DCS risk due to the increase in EVA frequency. If there is an occurrence of DCS during a mission, appropriate downtime needs to be accounted for. Treatment for DCS requires crewmember to stop the current EVA and return to the habitat. This impacts the current EVA the crew is performing, could potentially delay the next EVA, and increases the chance of the crewmember being unable to perform future EVAs. Capturing the downtime and impact of that downtime based on the number of DCS occurrences allows us to better understand how the risk associated with DCS affects the overall medical risk and completion of missions that have more frequent EVA tempo. There are preventative strategies and mitigation countermeasures to decrease the chance of DCS occurring such as different prebreathe protocols, variable suit pressure, and vehicle pressure settings. Modeling the medical risk with and without different DCS countermeasures enables quantitative comparisons of risk reduction associated with each DCS countermeasure. We present results on how these countermeasures affect medical risks and quantify changes in the medical kit contents with respect to the countermeasures implemented within Artemis-class missions.

Clara Gasiewski↗

NASA NTRSDate not supplied

Evaluating Extravehicular Activity Access Options for a Lunar Surface Habitat

NASA’s upcoming return to the moon includes a plan for longer duration lunar missions that prioritize science and surface exploration. The current Artemis Base Camp reference proposes a Surface Habitat (SH) that will support 2 to 4 crewmembers with adequate capability for living and working for 30 days or more. An important aspect of the SH’s design will be its ability to support a high frequency of Extravehicular Activities (EVAs) for scientific purposes. There are multiple airlock designs that can support EVA access from inside the SH out to the lunar surface. This paper explores three unique options for EVA access: a traditional airlock, a suitlock, and a suitport-airlock.A traditional airlock is accessed by use of a hatch, crewmembers don and doff their EVA suits inside the airlock, and it must be depressurized and repressurized for every EVA. A suitlock is also depressurized and repressurized for every EVA but thesuits are donned through a suitport attached to the airlock bulkhead. A suitport-airlock is access through suitports that are attached to the airlock bulkhead as well, but the suitport-airlock stays in vacuum, and it does not have to be depressurized and repressurized for each EVA. This study also evaluated the use of an Airlock Airsave System in the cases of a traditional airlock and suitlock. This system captures a fraction of the airlock gas instead of venting all of the gas pre-EVA. The captured gas isthen used to partially repressurize the airlock post-EVA.In this study, each option is evaluated based on seven different areas of analysis. The metrics include overhead time for EVAs, dust mitigation, consumables for resupply mass, systems mass, system power, safety and mission assurances, and programmatic considerations. The EVA access options are evaluated and compared under each area of analysis. While the baseline case assumes the SH is at 8.2 psia, the authors also investigate the impact of a 10.2 psia habitat as an alternative in this analysis. Following the conclusion of the analysis, the authors recommend the usage of a Suitport-Airlock for Lunar SH missions and detail the reasoning behind the recommendation.

EVA↗

DOE OSTI2019

Rheology, Mechanical Properties and Morphology of Poly(lactic acid)/Ethylene Vinyl Acetate Blends

In this work, the effect of ethylene vinyl acetate (EVA) content on the rheology, mechanical properties, and morphology of poly (lactic acid) (PLA)/EVA blends was investigated. Differential Scanning Calorimetry (DSC) showed that the addition of EVA to PLA decreased the degree of crystallinity of PLA. Dynamic Mechanical Thermal Analysis (DMTA) results showed that the presence of EVA copolymer increased the cold crystallization temperature (T{sub cc}) of PLA. The addition of 10% of EVA to PLA substantially increased the impact strength. Morphology analysis by Scanning Electron Microscopy (SEM) indicated the immiscibility between PLA and EVA phases and an in increase the EVA average dispersed phase domains size with the increase in EVA content. Rheological measurements under oscillatory shear flow showed that storage modulus (G′) increased with the increase in the EVA content at low frequencies and is related to the increase in the EVA dispersed phase domains size, as also observed by relaxation spectrum analysis. Cole–Cole plots of imaginary viscosity (η″) versus real viscosity (η′) and Han plots of storage modulus (G′) versus loss modulus (G″) indicated that PLA and EVA phases are immiscible, as also observed by SEM.

36 MATERIALS SCIENCE↗

NASA NTRS2011

An Alternative Approach to Human Servicing of Manned Earth Orbiting Spacecraft

As manned spacecraft have grown larger and more complex, they have come to rely on spacewalks or Extravehicular Activities (EVA) for both mission success and crew safety. Typically these spacecraft maintain all of the hardware and trained personnel needed to perform an EVA on-board at all times. Maintaining this capability requires volume and up-mass for storage of EVA hardware, crew time for ground and on-orbit training, and on-orbit maintenance of EVA hardware . This paper proposes an alternative methodology to utilize launch-on-need hardware and crew to provide EVA capability for space stations in Earth orbit after assembly complete, in the same way that most people would call a repairman to fix something at their home. This approach would not only reduce ground training requirements and save Intravehicular Activity (IVA) crew time in the form of EVA hardware maintenance and on-orbit training, but would also lead to more efficient EVAs because they would be performed by specialists with detailed knowledge and training stemming from their direct involvement in the development of the EVA. The on-orbit crew would then be available to focus on the immediate response to the failure as well as the day-to-day operations of the spacecraft and payloads. This paper will look at how current ISS unplanned EVAs are conducted, including the time required for preparation, and offer alternatives for future spacecraft utilizing lessons learned from ISS. As this methodology relies entirely on the on-time and on-need launch of spacecraft, any space station that utilized this approach would need a robust transportation system including more than one launch vehicle capable of carrying crew. In addition the fault tolerance of the space station would be an important consideration in how much time was available for EVA preparation after the failure. Each future program would have to weigh the risk of on-time launch against the increase in available crew time for the main objective of the spacecraft.

Mularski, John↗

NASA NTRS2014

Extravehicular Activity Asteroid Exploration and Sample Collection Capability

One of the challenging primary objectives associated with NASA's Asteroid Redirect Crewed Mission (ARCM) is to demonstrate deep space Extravehicular Activity (EVA) and tools and to obtain asteroid samples to return to Earth for further study. Prior Shuttle and International Space Station (ISS) spacewalks have benefited from engineered EVA interfaces which have been designed and manufactured on Earth. Rigid structurally mounted handrails, and tools with customized interfaces and restraints optimize EVA performance. For ARCM, EVA complexity increases due to the uncertainty of the asteroid properties. The variability of rock size, shape and composition, as well as behavior of the asteroid capture mechanism will complicate EVA translation, tool restraint, and body stabilization. The unknown asteroid hardness and brittleness will complicate tool use. The rock surface will introduce added safety concerns for cut gloves and debris control. Feasible solutions to meet ARCM EVA objectives were identified using experience gained during Apollo, Shuttle, and ISS EVAs, terrestrial mountaineering practices, NASA Extreme Environment Mission Operations (NEEMO) 16 mission, and during Neutral Buoyancy Laboratory testing in the Modified Advanced Crew Escape Suit (MACES) suit. This paper will summarize the overall operational concepts for conducting EVAs for the ARCM mission including translation paths and body restraint methods, potential tools used to extract the samples, design implications for the Asteroid Redirect Vehicle (ARV) for EVA, and the results of early development testing of potential EVA tasks.

Sipila, Stephanie A.↗

NASA NTRS2014

Extravehicular Activity Asteroid Exploration and Sample Collection Capability

One of the challenging primary objectives associated with NASA's Asteroid Redirect Crewed Mission (ARCM) is to demonstrate deep space Extravehicular Activity (EVA) and tools and to obtain asteroid samples to return to Earth for further study. Prior Shuttle and International Space Station (ISS) spacewalks have benefited from engineered EVA interfaces which have been designed and manufactured on Earth. Rigid structurally mounted handrails, and tools with customized interfaces and restraints optimize EVA performance. For ARCM, EVA complexity increases due to the uncertainty of the asteroid properties. The variability of rock size, shape and composition, as well as behavior of the asteroid capture mechanism will complicate EVA translation, tool restraint, and body stabilization. The unknown asteroid hardness and brittleness will complicate tool use. The rock surface will introduce added safety concerns for cut gloves and debris control. Feasible solutions to meet ARCM EVA objectives were identified using experience gained during Apollo, Shuttle, and ISS EVAs, terrestrial mountaineering practices, NASA Extreme Environment Mission Operations (NEEMO) 16 mission, and during Neutral Buoyancy Laboratory testing in the Modified Advanced Crew Escape Suit (MACES) suit. This paper will summarize the overall operational concepts for conducting EVAs for the ARCM mission including translation paths and body restraint methods, potential tools used to extract the samples, design implications for the Asteroid Redirect Vehicle (ARV) for EVA, and the results of early development testing of potential EVA tasks.

Sipila, Stephanie A.↗

NASA NTRS2014

Modified Advanced Crew Escape Suit Intravehicular Activity Suit for Extravehicular Activity Mobility Evaluations

The use of an intravehicular activity (IVA) suit for a spacewalk or extravehicular activity (EVA) was evaluated for mobility and usability in the Neutral Buoyancy Laboratory (NBL) environment at the Sonny Carter Training Facility near NASA Johnson Space Center in Houston, Texas. The Space Shuttle Advanced Crew Escape Suit was modified to integrate with the Orion spacecraft. The first several missions of the Orion Multi-Purpose Crew Vehicle will not have mass available to carry an EVA-specific suit; therefore, any EVA required will have to be performed by the Modified Advanced Crew Escape Suit (MACES). Since the MACES was not designed with EVA in mind, it was unknown what mobility the suit would be able to provide for an EVA or whether a person could perform useful tasks for an extended time inside the pressurized suit. The suit was evaluated in multiple NBL runs by a variety of subjects, including crewmembers with significant EVA experience. Various functional mobility tasks performed included: translation, body positioning, tool carrying, body stabilization, equipment handling, and tool usage. Hardware configurations included with and without Thermal Micrometeoroid Garment, suit with IVA gloves and suit with EVA gloves. Most tasks were completed on International Space Station mock-ups with existing EVA tools. Some limited tasks were completed with prototype tools on a simulated rocky surface. Major findings include: demonstrating the ability to weigh-out the suit, understanding the need to have subjects perform multiple runs prior to getting feedback, determining critical sizing factors, and need for adjusting suit work envelope. Early testing demonstrated the feasibility of EVA's limited duration and limited scope. Further testing is required with more flight-like tasking and constraints to validate these early results. If the suit is used for EVA, it will require mission-specific modifications for umbilical management or Primary Life Support System integration, safety tether attachment, and tool interfaces. These evaluations are continuing through calendar year 2014.

Watson, Richard D.↗

NASA NTRS2017

An Alternative Approach to Human Servicing of Crewed Earth Orbiting Spacecraft

As crewed spacecraft have grown larger and more complex, they have come to rely on spacewalks, or Extravehicular Activities (EVA), for mission success and crew safety. Typically, these spacecraft maintain all of the hardware and trained personnel needed to perform an EVA on-board at all times. Maintaining this capability requires volume and up-mass for storage of EVA hardware, crew time for ground and on-orbit training, and on-orbit maintenance of EVA hardware. This paper proposes an alternative methodology, utilizing launch on-need hardware and crew to provide EVA capability for space stations in Earth orbit after assembly complete, in the same way that one would call a repairman to fix something at their home. This approach would reduce ground training requirements, save Intravehicular Activity (IVA) crew time in the form of EVA hardware maintenance and on-orbit training, and lead to more efficient EVAs because they would be performed by specialists with detailed knowledge and training stemming from their direct involvement in the development of the EVA. The on-orbit crew would then be available to focus on the immediate response to the failure as well as the day-to-day operations of the spacecraft and payloads. This paper will look at how current unplanned EVAs are conducted, including the time required for preparation, and offer alternatives for future spacecraft. As this methodology relies on the on-time and on-need launch of spacecraft, any space station that utilized this approach would need a robust transportation system including more than one launch vehicle capable of carrying crew. In addition, the fault tolerance of the space station would be an important consideration in how much time was available for EVA preparation after the failure. Each future program would have to weigh the risk of on-time launch against the increase in available crew time for the main objective of the spacecraft.

Mularski, John R.↗

NASA NTRSDate not supplied

Evaluation of Planetary Extravehicular Activity Prebreathe Protocols using a 56.5 kPa, 34% O2, 66% N2 Saturation Cabin Atmosphere in an 11-day Hypobaric Hypoxia Study

INTRODUCTION: Apollo missions used 100% O2 cabin atmospheres which effectively eliminated the risk of decompression sickness (DCS) during Lunar extravehicular activities (EVAs, ‘spacewalks’); however, this atmosphere presented a flammability risk that is no longer acceptable to NASA. Denitrogenation prebreathe protocols used to mitigate DCS risk for Space Shuttle and International Space Station EVAs are validated for the microgravity environment, but the significantly increased risk of DCS during equivalent ambulatory surface EVAs make these protocols inapplicable to planetary/Lunar missions. A cabin/vehicle “Exploration Atmosphere” of 56.5 kPa (8.2 psia), 34% O2, 66% N2 has been recommended by NASA for future Moon and Mars missions as a compromise that balances subsequent pre-EVA prebreathe duration, hypoxia, and flammability risk, assuming a 29.6 kPa (4.3 psi) spacesuit. Prebreathe validation studies were initiated utilizing a three-story 6m diameter hypobaric chamber at NASA’s Johnson Space Center. Here, we report the results of a 11-day human-in-the-loop system checkout. METHODS: Six volunteers lived in a hyboparic chamber for 11 days with an ‘exploration atmosphere’ of 56.6kPa/34% O2 66% N2. Subjects acclimated to the exploration atmosphere for 48hrs and thereafter participated in five 6-hour simulated EVAs at 34kPa/85% O2 / 15% N2 over the course of 11 days. Prior to each simulated EVA, subjects underwent a 20-minute prebreathe at 85% O2. The EVA simulation was designed to include tasks that are physically and ergonomically representative of future planetary EVAs, proportionate to the subject’s VO2max. Decompression stress was evaluated during the simulated EVA by serial doppler and echocardiographs alternating every 15min, as well as clinical monitoring for DCS signs/symptoms. RESULTS AND DISCUSSION: Venous gas emboli (VGE) were present in 3 of 6 subjects during EVAs, with peak Grade II VGE as evaluated by Doppler and a peak Eftedal-Brubakk score of 5 by cardiac ultrasonography. Two cases of DCS were diagnosed during the 11-day test chamber. No acute hypoxic symptoms were noted. Musculoskeletal and gastrointestinal complaints were noted, likely associated with the exercise load and the food system. Two cases of DCS (8%) does not cross either accept or reject pre-test criterion, so an additional study is planned for 2023 to meet our pre-test thresholds.

Alejandro Garbino↗

NASA NTRS1993

Space Station maintenance studies using plaid graphics

The Graphics Analysis Facility (GRAF) has been used frequently to study extravehicular activity (EVA) maintenance scenarios on Space Station Freedom. The ability to use 3-dimensional visualization gives one a more accurate estimate of the Space Station environment. Moreover, human EVA and robotic kinematics can be accurately simulated for columetric reach and collision detection analysis. An animation of this kind was developed for a research group at JSC to study and discover problem areas involved with doing external Space Station maintenance tasks. On the EVA side, it was discovered that items such as handholds and temporary restraint mechanisms should more effectively facilitate EVA movement about the Space Station structure for the suited personnel. Issues concerning CETA cart configuration, PWP storage locations, and locations of EVA storage areas were also identified by use of the animation. In the area of EVA versus robotics, it was found that there is a strong desire to make EVA and robotics interfaces compatible on items such as replacement units and unpressurized logistics carriers. The animation also showed that the use of robotics within an EVA task increases the difficulty and duration of the task setup, leaving less time available for the maintenance task itself. Graphics animation provides a mechanism to simultaneously analyze several mission parameters (i.e., EVA reach, volumetric analysis, and task timelines), and thus, it has proven to be an effective method for mission evaluation.

Helm, Mary E.↗

NASA NTRS2009

Metabolic and Subjective Results Review of the Integrated Suit Test Series

Crewmembers will perform a variety of exploration and construction activities on the lunar surface. These activities will be performed while inside an extravehicular activity (EVA) spacesuit. In most cases, human performance is compromised while inside an EVA suit as compared to a crewmember s unsuited performance baseline. Subjects completed different EVA type tasks, ranging from ambulation to geology and construction activities, in different lunar analog environments including overhead suspension, underwater and 1-g lunar-like terrain, in both suited and unsuited conditions. In the suited condition, the Mark III (MKIII) EVA technology demonstrator suit was used and suit pressure and suit weight were parameters tested. In the unsuited conditions, weight, mass, center of gravity (CG), terrain type and navigation were the parameters. To the extent possible, one parameter was varied while all others were held constant. Tests were not fully crossed, but rather one parameter was varied while all others were left in the most nominal setting. Oxygen consumption (VO2), modified Cooper-Harper (CH) ratings of operator compensation and ratings of perceived exertion (RPE) were measured for each trial. For each variable, a lower value correlates to more efficient task performance. Due to a low sample size, statistical significance was not attainable. Initial findings indicate that suit weight, CG and the operational environment can have a large impact on human performance during EVA. Systematic, prospective testing series such as those performed to date will enable a better understanding of the crucial interactions of the human and the EVA suit system and their environment. However, work remains to be done to confirm these findings. These data have been collected using only unsuited subjects and one EVA suit prototype that is known to fit poorly on a large demographic of the astronaut population. Key findings need to be retested using an EVA suit prototype better suited to a larger anthropometric portion of the astronaut population, and elements tested only in the unsuited condition need to be evaluated with an EVA suit and appropriate analog environment.

Norcross, J.R.↗

NASA NTRSDate not supplied

JETT3: A Holistic, Integrated Analog for Artemis Lunar Surface Exploration

Since 1972, NASA astronauts have performed hundreds of Extravehicular Activities (EVAs) in support of Skylab, Space Shuttle and International Space Station missions. Not since Apollo, however, have EVAs been driven by discovery-based principles of scientific exploration. Upcoming Artemis missions are challenged to build on lessons learned from Apollo, merging 50 years of EVA experience with the planetary science community’s expertise in the remote surface exploration of Mars. The highest-fidelity preparation for Artemis includes both operational and scientific underpinning to represent the complete, complex picture of lunar surface operations. The Joint EVA & Human Surface Mobility Test Team (JETT) is an interdisciplinary team providing such an environment for collaborative analog testing. JETT builds upon prior analog campaigns (e.g., [1, 2]) to provide high-fidelity environments for hardware and concept of operations development. Sponsored by the NASA EVA & Human Surface Mobility Program (EHP), JETT includes representatives from EHP, NASA Engineering, the Science Mission Directorate (SMD), Human Health & Performance, and the Flight Operations Directorate (FOD). JETT tests evaluate NASA reference designs for EVA (e.g., suits and tools), address gaps and risks for Artemis lunar surface operations, develop capabilities for EVA and science tasks, enable technology maturation, and provide training for Artemis EVA operations. JETT3, the final JETT field test of FY22, occurred Oct 3-11, 2022 in the San Francisco Volcanic Field north of Flagstaff, AZ. The test focused on developing the Artemis concept of operations and systems, including integrating an Artemis-like Science Team into a NASA Flight Control Team (FCT) to plan and execute a series of simulated lunar EVAs in an environment analogous to Artemis 3.

T. E. Caswell↗

NASA NTRSDate not supplied

JETT3: A Holistic, Integrated Analog for Artemis Lunar Surface Exploration

Since 1972, NASA astronauts have performed hundreds of Extravehicular Activities (EVAs) in support of Skylab, Space Shuttle and International Space Station missions. Not since Apollo, however, have EVAs been driven by discovery-based principles of scientific exploration. Upcoming Artemis missions are challenged to build on lessons learned from Apollo, merging 50 years of EVA experience with the planetary science community’s expertise in the remote surface exploration of Mars. The highest-fidelity preparation for Artemis includes both operational and scientific underpinning to represent the complete, complex picture of lunar surface operations. The Joint EVA & Human Surface Mobility Test Team (JETT) is an interdisciplinary team providing such an environment for collaborative analog testing. JETT builds upon prior analog campaigns (e.g., [1, 2]) to provide high-fidelity environments for hardware and concept of operations development. Sponsored by the NASA EVA & Human Surface Mobility Program (EHP), JETT includes representatives from EHP, NASA Engineering, the Science Mission Directorate (SMD), Human Health & Performance, and the Flight Operations Directorate (FOD). JETT tests evaluate NASA reference designs for EVA (e.g., suits and tools), address gaps and risks for Artemis lunar surface operations, develop capabilities for EVA and science tasks, enable technology maturation, and provide training for Artemis EVA operations. JETT3, the final JETT field test of FY22, occurred Oct 3-11, 2022 in the San Francisco Volcanic Field north of Flagstaff, AZ. The test focused on developing the Artemis concept of operations and systems, including integrating an Artemis-like Science Team into a NASA Flight Control Team (FCT) to plan and execute a series of simulated lunar EVAs in an environment analogous to Artemis 3.

T. E. Caswell↗

NASA NTRSDate not supplied

A Historical Overview of International Space Station Extravehicular Activity Meteoroid and Orbital Debris Risk

Nearly 300 spacewalks have been conducted over the last 25 years to help build and maintain the International Space Station (ISS). During the nearly 2,000 hours of extra-vehicular activity (EVA), crew members wear extra-vehicular mobility unit (EMU) “spacesuits” to mitigate hazards of the space environment including impacts from meteoroid and orbital debris (MMOD) particles. NASA includes detailed EMU MMOD risk analyses as part of the ISS EVA review and approval process. This paper provides a general historical overview of the ISS EVA MMOD risks and the associated risk assessment process. The NASA Johnson Space Center (JSC) Hypervelocity Impact Technology (HVIT) Team produces the ISS EVA MMOD risk analyses using the Bumper3 MMOD risk analysis code in conjunction with detailed information about the EVA including crew-member EVA work sites, crew translation paths, suit orientation, and duration. Detailed physical models of the EMU spacesuits and the ISS are included and tailored for each EVA analysis. Two types of MMOD risk are included: (1) Penetration, and (2) Catastrophic. Penetration risk is for any size leak in the EMU suit. Catastrophic risk is a subset of Penetration Risk and only includes penetrations that cause a 4mm diameter hole (or larger) in the inner “bladder” layer of the EMU suit. This size hole will exceed the ability of the EMU suit to compensate. The MMOD risk analyses also utilize the latest orbital debris environment and meteoroid environment models including additional transient factors to account for recent satellite break-ups and annual meteor storms. These additional factors and the associated increase in EVA MMOD risk are considered when scheduling an EVA to reduce EMU MMOD risk.

Dana M. Lear↗

NASA NTRSDate not supplied

A Review of International Space Station Extravehicular Activity Micrometeoroid and Orbital Debris Risk

Nearly 300 spacewalks have been conducted over the last 25 years to support the construction and maintenance of the International Space Station (ISS). During the nearly 2,000 hours of extra-vehicular activity (EVA), crew wore extra-vehicular mobility unit (EMU) “spacesuits” to help mitigate hazards of the space environment including impacts from micrometeoroid and orbital debris (MMOD) particles. The National Aeronautics and Space Administration (NASA) conducts detailed EMU MMOD risk analyses as part of the ISS EVA review and approval process. This paper provides a general historical overview of the ISS EVA MMOD risks and the associated risk assessment process. The NASA Johnson Space Center (JSC) Hypervelocity Impact Technology (HVIT) Team produces the ISS EVA MMOD risk analyses using the Bumper MMOD risk analysis code in conjunction with detailed information about the EVA including crew member EVA work sites, crew translation paths, suit orientation, and durations. Detailed physical models of the EMU spacesuit and the ISS are included and tailored for each EVA analysis. Two types of MMOD risk are included: (1) Penetration, and (2) Catastrophic. Penetration risk is for any size leak in the EMU suit. Catastrophic risk is a subset of Penetration Risk and only includes penetrations that cause a 4mm diameter hole (or larger) in the pressure-maintaining “bladder” layer of the EMU suit. This size hole will exceed the ability of the EMU suit to compensate. The MMOD risk analyses also utilize the latest orbital debris environment and meteoroid environment models including additional transient factors to account for recent satellite break-ups and annual meteor storms. These additional factors and the associated increase in EVA MMOD risk are considered when scheduling EVAs to reduce EMU MMOD risk.

Dana M. Lear↗

NASA NTRSDate not supplied

A Review of International Space Station Extravehicular Activity Micrometeoroid and Orbital Debris Risk

Nearly 300 spacewalks have been conducted over the last 25 years to support the construction and maintenance of the International Space Station (ISS). During the nearly 2,000 hours of extra-vehicular activity (EVA), crew wore extra-vehicular mobility unit (EMU) “spacesuits” to help mitigate hazards of the space environment including impacts from micrometeoroid and orbital debris (MMOD) particles. The National Aeronautics and Space Administration (NASA) conducts detailed EMU MMOD risk analyses as part of the ISS EVA review and approval process. This paper provides a general historical overview of the ISS EVA MMOD risks and the associated risk assessment process. The NASA Johnson Space Center (JSC) Hypervelocity Impact Technology (HVIT) Team produces the ISS EVA MMOD risk analyses using the Bumper MMOD risk analysis code in conjunction with detailed information about the EVA including crew member EVA work sites, crew translation paths, suit orientation, and durations. Detailed physical models of the EMU spacesuit and the ISS are included and tailored for each EVA analysis. Two types of MMOD risk are included: (1) Penetration, and (2) Catastrophic. Penetration risk is for any size leak in the EMU suit. Catastrophic risk is a subset of Penetration Risk and only includes penetrations that cause a 4mm diameter hole (or larger) in the pressure-maintaining “bladder” layer of the EMU suit. This size hole will exceed the ability of the EMU suit to compensate. The MMOD risk analyses also utilize the latest orbital debris environment and meteoroid environment models including additional transient factors to account for recent satellite break-ups and annual meteor storms. These additional factors and the associated increase in EVA MMOD risk are considered when scheduling EVAs to reduce EMU MMOD risk.

Dana M. Lear↗