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Weld-ASSIST: Weldability Assessment for In-Space Conditions using a Digital Twin
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By NASA
3 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
AS16-116-18653 (23 April 1972) — Astronaut Charles M. Duke Jr., Apollo 16 lunar module pilot, stands at a big rock adjacent (south) to the huge “House Rock” (barely out of view at right edge). Note shadow at extreme right center where the two moon-exploring crew members of the mission sampled what they referred to as the “east-by-west split of House Rock” or the open space between this rock and “House Rock”. At their post-mission press conference, the crewmen expressed the opinion that this rock was once a part of “House Rock” which had broken away. The two sampled the big boulder seen here also. Duke has a sample bag in his hand, and a lunar surface rake leans against the large boulder. Astronaut John W. Young, commander, exposed this view with a color magazine in his 70mm Hasselblad camera. While astronauts Young and Duke descended in the Apollo 16 Lunar Module (LM) “Orion” to explore the Descartes highlands landing site on the moon, astronaut Thomas K. Mattingly II, command module pilot, remained with the Command and Service Modules (CSM) “Casper” in lunar orbit.NASA The goals of the working group were to:
Endorse or recommend changes to H2S SMAC levels that had been proposed by the JSC Toxicology Laboratory Review a draft H2S SMAC manuscript prepared by the JSC Toxicology Laboratory Provide any additional insight and consideration regarding H2S toxicity that should be considered for spaceflight programs Background
The NASA Spaceflight Human-System Standard (NASA-STD-3001) establishes that vehicle systems shall limit atmospheric contamination below established limits [V2 6050] Atmosphere Contamination Limit. The JSC Toxicology Laboratory maintains the JSC 20584 Spacecraft Maximum Allowable Concentrations for Airborne Contaminants document, which contains a table of SMAC values for a variety of chemicals including carbon monoxide, ammonia, heavy metals, and a wide range of volatile organic compounds. SMACs are documented for 1-hr, 24-hr, 7-day, 30-day, 180-day, and 1000-day time spans for each chemical, and express the maximum concentration to which spaceflight crew can be exposed for that duration.
Read More The organ system that is affected as well as the effect (symptoms) are also documented for each SMAC. For more information on SMACs, see this article Exposure Guidelines (SMACs and SWEGs) – NASA and the OCHMO Spaceflight Toxicology technical brief technical brief.
Read More A SMAC value for hydrogen sulfide has not previously been established since it has not been of concern in spacecraft. However, with Artemis missions returning to the moon there is a possibility that H2S could be released within spacecraft during lunar sample return, given that this compound may be a component of lunar polar ice. H2S has an intense smell of rotten eggs and therefore has a distracting psychological element. Physiologically it has been shown to be an irritant at low concentrations and in high concentrations can potentially lead to neurological effects and unconsciousness.
Hydrogen sulfide SMAC values will define safe limits for spaceflight crews on future missions and could drive new requirements for monitoring and mitigation of this chemical during spaceflight.
Read More Conclusions
Key points of the review were:
The proposed 1-hour, 24-hour, 7-day, 30-day, and 180-day SMAC values were deemed appropriate and were endorsed by each of the panel members. The proposed 1000-day SMAC value is so low that the panel’s opinion is that this SMAC may not be attainable due to human-generated sources, and that these concentrations do not represent a true toxicological risk. The recommendation is to eliminate the 1000-day SMAC, or to call it a guideline. The general SMAC calculation approach and inclusion of safety factors is logical, although some additional rationale would be justified. Interactive and additive effects with other substances are considered negligible, particularly at these low concentrations. Microgravity-induced physiological changes are unlikely to exacerbate hydrogen sulfide exposure at these low concentrations. Recommendations were made with the understanding that these SMACs apply to pre-screened, healthy astronauts. For private spaceflight participants who may not be as well screened, the panel recommended individual physician attention and a review of all SMACs (including hydrogen sulfide), to identify sensitivities in certain populations (existing disease states, etc.). Passive dosimetry technology is available and should be considered for long-term monitoring at these low concentrations. Following consideration of the panel’s recommendation, the NASA/TM-20240000101 Exposure Limits for Hydrogen Sulfide in Spaceflight was revised and released by the JSC toxicology group in January of 2024 and is available below.
Read More Astronaut Woody Hoburg replaces life support system components inside the International Space Station’s Destiny laboratory module.NASA About the Author
Kim Lowe
Human Systems Standards Integrator
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Last Updated Jan 17, 2025 Related Terms
Office of the Chief Health and Medical Officer (OCHMO) Human Health and Performance Humans in Space The Human Body in Space Keep Exploring Discover More Topics From OCHMO Standards
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By NASA
This map depicts global temperature anomalies for meteorological summer in 2024 (June, July, and August). It shows how much warmer or cooler different regions of Earth were compared to the baseline average from 1951 to 1980. (Credit: NASA/NOAA) Climate researchers from NASA and NOAA (National Oceanic and Atmospheric Administration) will release their annual assessments of global temperatures and discuss the major climate trends of 2024 during a media briefing at 12 p.m. EST Friday, Jan. 10.
NASA will share the briefing on the agency’s website at: https://www.nasa.gov/live.
Participants will include:
Gavin Schmidt, director, NASA’s Goddard Institute for Space Studies Russ Vose, chief, Monitoring and Assessment Branch, NOAA National Centers for Environmental Information Media interested in participating must RSVP to NOAA by the time of the event.
NASA and NOAA are stewards of global temperature data and independently produce a record of Earth’s surface temperatures and changes based on historical observations over land and ocean.
For more information about NASA’s Earth science programs, visit:
https://www.nasa.gov/earth
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Liz Vlock
Headquarters, Washington
202-358-1600
elizabeth.a.vlock@nasa.gov
Peter Jacobs
Goddard Space Flight Center, Greenbelt, Maryland
301-286-0535
peter.jacobs@nasa.gov
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By NASA
6 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
In-person participants L-R standing: Dave Francisco, Joanne Kaouk, Dr. Richard Moon, Dr. Tony Alleman, Dr. Sean Hardy, Sarah Childress, Kristin Coffey, Dr. Ed Powers, Dr. Doug Ebersole, Dr. Steven Laurie, Dr. Doug Ebert; L-R seated: Dr. Alejandro Garbino, Dr. Robert Sanders, Dr. Kristi Ray, Dr. Mike Gernhardt, Dr. Joseph Dervay, Dr. Matt Makowski). Not pictured: Dr. Caroline Fife In June 2024, the NASA Office of the Chief Health and Medical Officer (OCHMO) Standards Team hosted an independent assessment working group to review the status and progress of research and clinical activities intended to mitigate the risk of decompression sickness (DCS) related to patent foramen ovale (PFO) during spaceflight and associated ground testing and human subject studies.
Decompression sickness (DCS) is a condition which results from dissolved gases (primarily nitrogen) forming bubbles in the bloodstream and tissues. It is usually experienced in conditions where there are rapid decreases in ambient pressure, such as in scuba divers, high-altitude aviation, or other pressurized environments. The evolved gas bubbles have various physiological effects and can obstruct the blood vessels, trigger inflammation, and damage tissue, resulting in symptoms of DCS. NASA presently classifies DCS into two categories: Type I DCS, which is less severe, typically leads to musculoskeletal symptoms including pain in the joints or muscles, or skin rash. Type II DCS is more severe and commonly results in neurological, inner ear, and cardiopulmonary symptoms. The risk of DCS in spaceflight presents during extravehicular activities (EVAs) in which astronauts perform mission tasks outside the spaceflight vehicle while wearing a pressurized suit at a lower pressure than the cabin pressure. DCS mitigation protocols based on strategies to reduce systemic nitrogen load are implemented through the combination of habitat environmental parameters, EVA suit pressure, and breathing gas procedures (prebreathe protocols) to achieve safe and effective mission operations. The pathophysiology of DCS has still not been fully elucidated since cases occur despite the absence of detected gas bubbles but includes right to left shunting of venous gas emboli (VGE) via several potential mechanisms, one of which is a Patent Foramen Ovale (PFO).
From: Dr. Schochet & Dr. Lie, Pediatric Pulmonologists
Reference OCHMO-TB-037 Decompression Sickness (DCS) Risk Mitigation technical brief for additional information.
A PFO is a shunt between the right atrium and the left atrium of the heart, which is a persisting remnant of a physiological communication present in the fetal heart. Post-natal increases in left atrial pressure usually force the inter-septal valve against the septum secundum and within the first 2 years of life, the septae permanently fuse due to the development of fibrous adhesions. Thus, all humans are born with a PFO and approximately 75% of PFOs fuse following childbirth. For the 25% of the population’s whose PFOs do not fuse, ~6% have what is considered by some to be a large PFO (> 2 mm). PFO diameter can increase with age. The concern with PFOs is that with a right to left shunt between the atria, venous emboli gas may pass from the right atrium (venous) to the left atrium (arterial) (“shunt”), thus by-passing the normal lung filtration of venous emboli which prevent passage to the arterial system. Without filtration, bubbles in the arterial system may lead to a neurological event such as a stroke. Any activity that increases the right atrium/venous pressure over the left atrium/arterial pressure (such as a Valsalva maneuver, abdominal compression) may further enable blood and/or emboli across a PFO/shunt.
From: Nuffield Department of Clinical Neurosciences
The purpose of this working group was to review and provide analysis on the status and progress of research and clinical activities intended to mitigate the risk of PFO and DCS issues during spaceflight. Identified cases of DCS during NASA exploration atmosphere ground testing conducted in pressurized chambers led to the prioritization of the given topic for external review. The main goals of the working group included:
Quantification of any increased risk associated with the presence of a PFO during decompression protocols utilized in ground testing and spaceflight EVAs, as well as unplanned decompressions (e.g., cabin depressurization, EVA suit leak). Describe risks and benefits of PFO screening in astronaut candidates, current crewmembers, and chamber test subjects. What are potential risk reduction measures that could be considered if a person was believed to be at increased risk of DCS due to a PFO? What research and/or technology development is recommended that could help inform and/or mitigate PFO-related DCS risk? The working group took place over two days at NASA’s Johnson Space Center and included NASA subject matter experts and stakeholders, as well as invited external reviewers from areas including cardiology, hypobaric medicine, spaceflight medicine, and military occupational health. During the working group, participants were asked to review past reports and evidence related to PFOs and risk of DCS, materials and information regarding NASA’s current experience and practices, and case studies and subsequent decision-making processes. The working group culminated in an open-forum discussion where recommendations for current and future practices were conferred and subsequently summarized in a final summary report, available on the public NASA OCHMO Standards Team website.
The following key findings are the main take-aways from the OCHMO independent assessment:
In an extreme exposure/high-risk scenario, excluding individuals with a PFO and treating PFOs does not necessarily decrease the risk of DCS or create a ‘safe’ environment. It may create incremental differences and slightly reduce overall risk but does not make the risk zero. There are other physiological factors that also contribute to the risk of DCS that may have a larger impact (see 7.0 Other Physiological Factors in the findings section). Based on the available evidence and the risk of current decompression exposures (based on current NASA protocols and NASA-STD-3001 requirements to limit the risk of DCS), it is not recommended to screen for PFOs in any spaceflight or ground testing participants. The best strategy to reduce the risk of DCS is to create as safe an environment as possible in every scenario, through effective prebreathe protocols, safety, and the capability to rapidly treat DCS should symptoms occur. Based on opinion, no specific research is required at this time to further characterize PFOs with DCS and altitude exposure, due to the low risk and preference to institute adequate safe protocols and ensuring treatment availability both on the ground and in spaceflight. For engineering protocols conducted on the ground, it should be ensured that the same level of treatment capability (treatment chamber in the immediate vicinity of the testing) is provided as during research protocols. The ability to immediately treat a DCS case is critical in ensuring the safety of the test subjects. The full summary report includes detailed background information, discussion points from the working group, and conclusions and recommendations. The findings from the working group and resulting summary report will help to inform key stakeholders in decision-making processes for future ground testing and spaceflight operations with the main goal of protecting crew health and safety to ensure overall mission success.
Summary Report About the Author
Sarah D. Childress
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Last Updated Dec 31, 2024 Related Terms
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By NASA
Ken Freeman (center) receives the ATCA Award for ATM-X Digital Information Platform (DIP) from Rachel Jackson, Chair ATCA Board of Directors (left) and Carey Fagan, President and CEO ATCA (right).NASA Air Traffic Control Association (ATCA) Award to the NASA ATM-X Digital Information Platform (DIP) Team
In November 2024, the Digital Information Platform (DIP) team received the prestigious Industry Award from the Air Traffic Control Association (ATCA) at the annual ATCA Connect Conference in Washington, DC. The award recognized the team’s efforts in supporting NASA’s Sustainable Flight National Partnership (SFNP), which aims for net-zero carbon emissions from aviation by 2050. The DIP sub-project focuses on increasing access to digital aviation information to enable efficient and sustainable airspace operations. DIP team has been conducting live operational demonstrations in North Texas Metroplex environment since 2022 with commercial airlines on the Collaborative Digital Departure Reroute (CDDR) tool that applies machine learning to make predictions on runway availability, departure times, and arrival times. DIP has signed Space Act Agreements with five major US airlines to carryout operational evaluation of CDDR in complex metroplex environments and is now deploying the CDDR capability to Houston. CDDR machine learning algorithm intelligently provides re-routing options to the operators by using real time weather and operational data reducing delays, fuel burn and carbon emissions. DIP is part of the Air Traffic Management – eXploration (ATM-X) project, which is focused on transforming the air traffic management system to accommodate new air vehicles. More information on the ATCA award is at: https://www.atca.org/detail-pages/news/2024/11/15/atca-presents-annual-awards-at-atca-connect-recognizing-exceptional-efforts-made-to-the-worldwide-air-traffic-control-and-airspace-system.
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