Jump to content

Risk of Reduced Crew Health and Performance Due to Hypoxia


Recommended Posts

  • Publishers
Posted

1 min read

Preparations for Next Moonwalk Simulations Underway (and Underwater)

astronauts go through a "pre-breathing" period before eva
Astronauts Michael R. (Rich) Clifford and Linda M. Godwin, the assigned space-walking mission specialists for STS-76, go through a “pre-breathing” period on the Space Shuttle Atlantis’ middeck. This practice is normal procedure for space-walkers in preparation for their Extravehicular Activity (EVA) and the wearing of their Extravehicular Mobility Units (EMU). The photograph was taken with a 35mm camera by one of the crew members.

Human exploration missions will require robust, flexible Extravehicular Activity (EVA) architecture protocols that include the use of a reduced-pressure cabin atmosphere enabling staged denitrogenation. Use of this atmosphere could result in compromised health and performance to the crewmember due to exposure to mild hypobaric hypoxia; of most concern are the potential effects on the increased intracranial pressure, visual impairment, cognitive performance, sensorimotor dysfunction, oxidative damage, and sleep quality. In addition to hypobaric hypoxia associated with staged denitrogenation, there are additional factors that can result in hypoxic exposure to the crewmember, such as cabin depressurization, Environmental Control, and Life Support System (ECLSS) failure, toxic exposure, or crewmember illness/injury.

astronauts test a Personal Cabin Pressure Altitude Monitor
Jan Zysko (left) and Rich Mizell (right) test a Personal Cabin Pressure Altitude Monitor in an altitude chamber at Tyndall Air Force Base in Florida. Zysko invented the pager-sized monitor that alerts wearers of a potentially dangerous or deteriorating cabin pressure altitude condition, which can lead to life-threatening hypoxia. Zysko is chief of the KSC Spaceport Engineering and Technology directorate’s data and electronic systems branch. Mizell is a Shuttle processing engineer. The monitor, which has drawn the interest of such organizations as the Federal Aviation Administration for use in commercial airliners and private aircraft, was originally designed to offer Space Shuttle and Space Station crew members added independent notification about any depressurization
NASA

Directed Acyclic Graph Files

+ DAG File Information (HSRB Home Page)

+ Hypoxia Risk DAG and Narrative (PDF)

+ Hypoxia Risk DAG Code (TXT)

Human Research Program

+ Risk of Reduced Crew Health and Performance Due to Hypoxia

+ 2015 November Evidence Report (MSWord)

Share

Details

Last Updated
Mar 11, 2025
Editor
Robert E. Lewis

View the full article

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Similar Topics

    • By NASA
      A SpaceX Falcon 9 rocket carrying the company’s Dragon spacecraft is launched on NASA’s SpaceX Crew-10 mission to the International Space Station.NASA/Aubrey Gemignani Digital content creators are invited to register to attend the launch of NASA’s SpaceX Crew-11 mission to carry astronauts to the International Space Station for a science expedition as part of NASA’s Commercial Crew Program. This will be the 15th time a SpaceX Dragon spacecraft launched by a Falcon 9 rocket takes crews to the orbital laboratory. 
      Launch of the Crew-11 mission is targeted for no earlier than July 2025 on a SpaceX Falcon 9 rocket from Florida. The launch will carry NASA astronauts Commander Zena Cardman and Pilot Mike Fincke, and mission specialists JAXA (Japan Aerospace Exploration Agency) astronaut Kimiya Yui and Roscosmos cosmonaut Oleg Platonov. 
      If your passion is to communicate and engage the world online, then this is the event for you! Seize the opportunity to see and share the #Crew11 mission launch. 
      A maximum of 50 social media users will be selected to attend this two-day event and will be given exclusive access to NASA’s Kennedy Space Center in Florida. 
      NASA Social participants will have the opportunity to: 
      View a crewed launch of the SpaceX Falcon 9 rocket and Dragon spacecraft  Tour NASA facilities at the agency’s Kennedy Space Center in Florida  Meet and interact with Crew-11 subject-matter experts  Meet fellow space enthusiasts who are active on social media  NASA Social registration for the Crew-11 launch opens on Tuesday, April 15, and the deadline to apply is at 10 a.m. EDT on Monday, April 28. All social applications will be considered on a case-by-case basis. 
      APPLY NOW 
      Do I need to have a social media account to register? 
       Yes. This event is designed for people who: 
      Actively use multiple social networking platforms and tools to disseminate information to a unique audience.  Regularly produce new content that features multimedia elements.  Have the potential to reach a large number of people using digital platforms, or reach a unique audience, separate and distinctive from traditional news media and/or NASA audiences.  Must have an established history of posting content on social media platforms.  Have previous postings that are highly visible, respected and widely recognized.  Users on all social networks are encouraged to use the hashtag #NASASocial and #Crew11. Updates and information about the event will be shared on X via @NASASocial and @NASAKennedy, and via posts to Facebook and Instagram. 
      How do I register? 
      Registration for this event opens on Tuesday, April 15, and the deadline to apply is at 10 a.m. EDT on Monday, April 28. Registration is for one person only (you) and is non-transferable. Each individual wishing to attend must register separately. Each application will be considered on a case-by-case basis. 
      Can I register if I am not a U.S. citizen? 
      Yes, this event is open for all to apply, ages 18 years and older. 
      When will I know if I am selected? 
      After registrations have been received and processed, an email with confirmation information and additional instructions will be sent to those selected. We expect to send the acceptance notifications by May 30. 
      What are NASA Social credentials? 
      All social applications will be considered on a case-by-case basis. Those chosen must prove through the registration process they meet specific engagement criteria. 
      If you do not make the registration list for this NASA Social, you still can attend the launch offsite and participate in the conversation online. Find out about ways to experience a launch here. 
      What are the registration requirements? 
      Registration indicates your intent to travel to NASA’s Kennedy Space Center in Florida and attend the two-day event in person. You are responsible for your own expenses for travel, accommodations, food, and other amenities. You must be able to attend all days of NASA Social activities in order to view the launch
      Some events and participants scheduled to appear at the event are subject to change without notice. NASA is not responsible for loss or damage incurred as a result of attending. NASA, moreover, is not responsible for loss or damage incurred if the event is cancelled with limited or no notice. Please plan accordingly. 
      NASA Kennedy is a government facility. Those who are selected will need to complete an additional registration step to receive clearance to enter the secure areas. 
      IMPORTANT: To be admitted, you will need to provide two forms of unexpired government-issued identification; one must be a photo ID and match the name provided on the registration. Those without proper identification cannot be admitted. 
      For a complete list of acceptable forms of ID, please visit: NASA Credentialing Identification Requirements. 
      All registrants must be at least 18 years old. 
      What if the launch date changes? 
      Many different factors can cause a scheduled launch date to change multiple times. If the launch date changes, NASA may adjust the date of the NASA Social accordingly to coincide with the new target launch date. NASA will notify registrants of any changes by email. 
      If the launch is postponed, attendees may be invited to attend a later launch date but that is not guaranteed. 
      NASA Social attendees are responsible for any additional costs they incur related to any launch delay. We strongly encourage participants to make travel arrangements that are refundable and/or flexible. 
      What if I cannot come to the Kennedy Space Center? 
      If you cannot come to the Kennedy Space Center and attend all days in person, you should not register for the NASA Social. You can follow the conversation online using #NASASocial.  
      You can also become a virtual guest for NASA launches and milestone events. This free program gives access to curated resources, schedule changes, and mission specific information delivered straight to your inbox. Join us today! 
      You can watch the launch on NASA+. NASA will provide regular launch and mission updates on X at @NASA, @NASAKennedy, and @Commercial_Crew, as well as on NASA’s Commercial Crew Program blog. 
      If you cannot make this NASA Social, don’t worry; NASA is planning many other Socials in the near future at various locations! 
      Apply Now
      View the full article
    • By NASA
      NASA astronauts (left to right) Christina Koch, Victor Glover, Reid Wiseman, Canadian Space Agency Astronaut Jeremy Hansen. Credit: NASA/Josh Valcarcel The Artemis II test flight will be NASA’s first mission with crew under Artemis. Astronauts on their first flight aboard NASA’s Orion spacecraft will confirm all of the spacecraft’s systems operate as designed with crew aboard in the actual environment of deep space.  Through the Artemis campaign, NASA will send astronauts to explore the Moon for scientific discovery, economic benefits, and to build the foundation for the first crewed missions to Mars – for the benefit of all.

      The unique Artemis II mission profile will build upon the uncrewed Artemis I flight test by demonstrating a broad range of SLS (Space Launch System) and Orion capabilities needed on deep space missions. This mission will prove Orion’s critical life support systems are ready to sustain our astronauts on longer duration missions ahead and allow the crew to practice operations essential to the success of Artemis III and beyond.

      Leaving Earth
      The mission will launch a crew of four astronauts from NASA’s Kennedy Space Center in Florida on a Block 1 configuration of the SLS rocket. Orion will perform multiple maneuvers to raise its orbit around Earth and eventually place the crew on a lunar free return trajectory in which Earth’s gravity will naturally pull Orion back home after flying by the Moon. The Artemis II astronauts are NASA’s Reid Wiseman, Victor Glover, and Christina Koch, and CSA (Canadian Space Agency) astronaut Jeremy Hansen.

      The initial launch will be similar to Artemis I as SLS lofts Orion into space, and then jettisons the boosters, service module panels, and launch abort system, before the core stage engines shut down and the core stage separates from the upper stage and the spacecraft. With crew aboard this mission, Orion and the upper stage, called the interim cryogenic propulsion stage (ICPS), will then orbit Earth twice to ensure Orion’s systems are working as expected while still close to home. The spacecraft will first reach an initial orbit, flying in the shape of an ellipse, at an altitude of about 115 by 1,400 miles. The orbit will last a little over 90 minutes and will include the first firing of the ICPS to maintain Orion’s path. After the first orbit, the ICPS will raise Orion to a high-Earth orbit. This maneuver will enable the spacecraft to build up enough speed for the eventual push toward the Moon. The second, larger orbit will take approximately 23.5 hours with Orion flying in an ellipse between about 115 and 46,000 miles above Earth. For perspective, the International Space Station flies a nearly circular Earth orbit about 250 miles above our planet. 

      After the burn to enter high-Earth orbit, Orion will separate from the upper stage. The expended stage will have one final use before it is disposed through Earth’s atmosphere—the crew will use it as a target for a proximity operations demonstration. During the demonstration, mission controllers at NASA’s Johnson Space Center in Houston will monitor Orion as the astronauts transition the spacecraft to manual mode and pilot Orion’s flight path and orientation. The crew will use Orion’s onboard cameras and the view from the spacecraft’s windows to line up with the ICPS as they approach and back away from the stage to assess Orion’s handling qualities and related hardware and software. This demonstration will provide performance data and operational experience that cannot be readily gained on the ground in preparation for critical rendezvous, proximity operations and docking, as well as undocking operations in lunar orbit beginning on Artemis III.

      Checking Critical Systems
      Following the proximity operations demonstration, the crew will turn control of Orion back to mission controllers at Johnson and spend the remainder of the orbit verifying spacecraft system performance in the space environment. They will remove the Orion Crew Survival System suit they wear for launch and spend the remainder of the in-space mission in plain clothes, until they don their suits again to prepare for reentry into Earth’s atmosphere and recovery from the ocean.

      While still close to Earth, the crew will assess the performance of the life support systems necessary to generate breathable air and remove the carbon dioxide and water vapor produced when the astronauts breathe, talk, or exercise. The long orbital period around Earth provides an opportunity to test the systems during exercise periods, where the crew’s metabolic rate is the highest, and a sleep period, where the crew’s metabolic rate is the lowest. A change between the suit mode and cabin mode in the life support system, as well as performance of the system during exercise and sleep periods, will confirm the full range of life support system capabilities and ensure readiness for the lunar flyby portion of the mission.

      Orion will also checkout the communication and navigation systems to confirm they are ready for the trip to the Moon. While still in the elliptical orbit around Earth, Orion will briefly fly beyond the range of GPS satellites and the Tracking and Data Relay Satellites of NASA’s Space Network to allow an early checkout of agency’s Deep Space Network communication and navigation capabilities. When Orion travels out to and around the Moon, mission control will depend on the Deep Space Network to communicate with the astronauts, send imagery to Earth, and command the spacecraft.

      After completing checkout procedures, Orion will perform the next propulsion move, called the translunar injection (TLI) burn. With the ICPS having done most of the work to put Orion into a high-Earth orbit, the service module will provide the last push needed to put Orion on a path toward the Moon. The TLI burn will send crew on an outbound trip of about four days and around the backside of the Moon where they will ultimately create a figure eight extending over 230,000 miles from Earth before Orion returns home.

      To the Moon and “Free” Ride Home
      On the remainder of the trip, astronauts will continue to evaluate the spacecraft’s systems, including demonstrating Earth departure and return operations, practicing emergency procedures, and testing the radiation shelter, among other activities.

      The Artemis II crew will travel approximately 4,600 miles beyond the far side of the Moon. From this vantage point, they will be able to see the Earth and the Moon from Orion’s windows, with the Moon close in the foreground and the Earth nearly a quarter-million miles in the background.

      With a return trip of about four days, the mission is expected to last about 10 days. Instead of requiring propulsion on the return, this fuel-efficient trajectory harnesses the Earth-Moon gravity field, ensuring that—after its trip around the far side of the Moon—Orion will be pulled back naturally by Earth’s gravity for the free return portion of the mission.

      Two Missions, Two Different Trajectories
      Following Artemis II, Orion and its crew will once again travel to the Moon, this time to make history when the next astronauts walk on the lunar surface. Beginning with Artemis III, missions will focus on establishing surface capabilities and building Gateway in orbit around the Moon.

      Through Artemis, NASA will explore more of the Moon than ever before and create an enduring presence in deep space.
      View the full article
    • By NASA
      2 min read
      Preparations for Next Moonwalk Simulations Underway (and Underwater)
      NASA uses radio frequency (RF) for a variety of tasks in space, including communications. The Europa Clipper RF panel — the box with the copper wiring near the top — will send data carried by radio waves through the spacecraft between the electronics and eight antennas. Credit: NASA Even before we’re aware of heart trouble or related health issues, our bodies give off warning signs in the form of vibrations. Technology to detect these signals has ranged from electrodes and patches to watches. Now, an innovative wall-mounted technology is capable of monitoring vital signs. Advanced TeleSensors Inc. developed the Cardi/o Monitor with an exclusive license from NASA’s Jet Propulsion Laboratory in Southern California. 

      Over the course of five years, NASA engineers created a small, inexpensive, contactless device to measure vital signs, a challenging task partly because monitoring heart rate requires picking out motions of about one three-thousandth of an inch, which are easily swamped by other movement in the environment.  

      By the late 1990s, hardware and computing technology could meet the challenge, and the NASA JPL team created a prototype the size of a thick textbook. It would emit a radio beam toward a stationary person, working similarly to a radar, and algorithms differentiated cardiac and respiratory activity from the “noise” of other movements.  

      When Sajol Ghoshal, now CEO of Austin, Texas-based Advanced TeleSensors, participated in a demonstration of the prototype, he saw the potential for in-home monitoring. By then, developing an affordable device was possible due to the miniaturization of sensors and computing technology.  
      The Cardi/o vital sign monitor uses NASA-developed technology to continually monitor vital signs. The data collected can be sent directly to medical care providers, cutting down on the number of home healthcare visits. Credit: Advanced TeleSensors Inc. The Cardi/o Monitor is 3 inches square and mounts to a ceiling or wall. It can detect vital signs from up to 10 feet. Multiple devices can be scattered throughout a house, with a smartphone app controlling settings and displaying all data on a single dashboard. The algorithms NASA developed detect heartbeat and respiration, and the company added heart rate variability detection that indicates stress and sleep apnea.  

      If there’s an anomaly, such as a dramatic heart rate increase, an alert in the app calls attention to the situation. Up to six months of data is stored in a secure cloud, making it accessible to healthcare providers. This limits the need for regular in-person visits, which is particularly important for conditions such as infectious diseases, which can put medical professionals and other patients at risk.  

      Through the commercialization of this life-preserving technology, NASA is at the heart of advancing health solutions.  
      Read More Share
      Details
      Last Updated Apr 07, 2025 Related Terms
      Technology Transfer & Spinoffs Spinoffs Technology Transfer Explore More
      2 min read NASA Cloud Software Helps Companies Find their Place in Space 
      Article 2 weeks ago 2 min read NASA Expertise Helps Record all the Buzz
      Article 3 weeks ago 2 min read What is a NASA Spinoff? We Asked a NASA Expert: Episode 53
      Article 1 month ago Keep Exploring Discover Related Topics
      Missions
      Humans in Space
      Jet Propulsion Laboratory – News
      Solar System

      View the full article
    • By NASA
      5 min read
      Preparations for Next Moonwalk Simulations Underway (and Underwater)
      In-person participants (L-R) – Back row: Jason Lytle, Stuart Lee, Eric Bershad, Ashot Sargsyan, Aaron Everson, Philip Wells, Sergi Vaquer Araujo, Steven Grover, John A. Heit, Mehdi Shishehbor, Laura Bostick; Middle row: Sarah Childress Taoufik, Stephan Moll, Brandon Macias, Kristin Coffey, Ann-Kathrin Vlacil, Dave Francisco; Front row: James Pavela, Doug Ebert, Kathleen McMonigal, Esther Kim, Emma Hwang; Not pictured: Tyson Brunstetter, J. D. Polk
      Online participants: Stephen Alamo, Mark Crowther, Steven Nissen, Mark Rosenberg, Jeffrey Weitz, R. Eugene Zierler, Serena Aunon, Tina Bayuse, Laura Beachy, Becky Brocato, Daniel Buckland, Jackie Charvat, Diana Cruz Topete, Quinn Dufurrena, Robert Haddon, Joanne Kaouk, Kim Lowe, Steve Laurie, Karina Marshall-Goebel, Sara Mason, Shannan Moynihan, James Pattarini, Devan Petersen, Ruth Reitzel, Donna Roberts, Lucia Roccaro, Mike Stenger, Terry Taddeo, Gavin Travers, Mary Van Baalen, Liz WarrenNASA In October 2024, NASA’s Office of the Chief Health and Medical Officer (OCHMO) initiated a working group to review the status and progress of research and clinical activities intended to mitigate the risk of venous thromboembolism (VTE) during spaceflight. The working group took place over two days at NASA’s Johnson Space Center; a second meeting on the topic was held in December 2024 at the European Space Agency (ESA) facility in Cologne, Germany.
      Read More about the Risk of VTE The working group was assembled from internal NASA subject matter experts (SMEs), the NASA OCHMO Standards Team, NASA and ESA stakeholders, and external SMEs, including physicians and medical professionals from leading universities and medical centers in the United States and Canada.

      Background
      Spaceflight Venous Thrombosis (SVT)
      Spaceflight Venous Thrombosis (SVT) refers to a phenomenon experienced during spaceflight in which a thrombus (blood clot) forms in the internal jugular vein (and/or associated vasculature) that may be symptomatic (thrombus accompanied by, but not limited to, visible internal jugular vein swelling, facial edema beyond “nominal” spaceflight adaptation, eyelid edema, and/or headache) or asymptomatic. Obstructive thrombi have been identified in a very small number of crewmembers, as shown in the figure below.

      Note that the figure below is for illustrative purposes only; locations are approximate, and size is not to scale.

      Approximate location of identified thrombi in crewmembers.Source: Modified from Cerebral Sinus Venous Thrombosis – University of Colorado Denver With treatment, crewmembers were able to complete their mission, and anticoagulants were discontinued several days prior to landing to minimize the risk of bleeding in the event of a traumatic injury. Some thromboses completely resolved post landing, and some required additional treatment.
      Pathophysiology of Venous Thromboembolism (VTE)
      The proposed pathogenesis of VTE is referred to as Virchow’s triad and suggests that VTE occurs as the result of:
      Alterations in blood flow (i.e., stasis), Vascular endothelial injury/changes, and/or, Alterations in the constituents of the blood leading to hypercoagulability (i.e., hereditary predisposition or acquired hypercoagulability). Note: pathophysiology are the changes that occur during a disease process; hypercoagulability is the increased tendency to develop blood to clots.
      The Virchow’s triad of risk factors for venous thrombosis.Bouchnita, 2017 Blood stasis, or venous stasis, refers to a condition in which the blood flow in the veins slows down which leads to pooling in the veins. This slowing of the blood may be due to vein valves becoming damaged or weak, immobility, and/or the absence of muscular contractions. Associated symptoms include swelling, skin changes, varicose veins, and slow-healing sores or ulcers. In terrestrial medicine, venous thrombosis is typically caused by damaged or weakened vein valves, which can be due to many factors, including aging, blood clots, varicose veins, obesity, pregnancy, sedentary lifestyle, estrogen use, and hereditary predisposition.

      Spaceflight Considerations
      Altered Venous Blood Flow and Spaceflight Associated Neuro-ocular Syndrome

      In addition to the terrestrial risk factors of VTE, there are physiological changes associated with spaceflight that are hypothesized to potentially play a role in the development of VTE in weightlessness. Specifically, researchers have explored the effects of the microgravity environment and subsequent observed headward fluid shifts that occur, and the potential impact on blood flow. Crewmembers onboard the International Space Station (ISS) experience weightlessness due to the microgravity environment and thus experience a sustained redistribution of bodily fluids from the legs toward the head. The prolonged headward fluid shifts during weightlessness results in facial puffiness, decreased leg volume, increased cardiac stroke volume, and decreased plasma volume.
      Crewmembers have also experienced altered blood flow during spaceflight, including retrograde venous blood flow (RVBF) (the backflow of venous blood towards the brain) or stasis (a stoppage or slowdown in the flow of blood). While the causes of the observed stasis and retrograde blood flow in spaceflight participants is not well understood, the potential clinical significance of the role it may have in the development of thrombus formation warrants further investigation.
      Doppler imaging of a retrograde flow in the left internal jugular vein.Yan & Seow, 2009 Other physiological concerns affected by fluid shifts are being studied to consider if any relation to VTE exists. Chronic weightlessness can cause bodily fluids such as blood and cerebrospinal fluid to move toward the head, which can lead to optic nerve swelling, folds in the retina, flattening of the back of the eye, and swelling in the brain. This collection of eye and brain changes is called “spaceflight associated neuro-ocular syndrome,” or SANS. Some astronauts only experience mild changes in space, while others have clinically significant outcomes. The long-term health outcome from these changes is unknown but actively being investigated. The risk of developing SANS is higher during longer-duration missions and remains a top research priority for scientists ahead of a Mars mission.
      Conclusions and Further Work
      Based on expert opinion and the assessment of the risk factors for thrombosis, an algorithm was developed to provide guidance for in-mission assessment and treatment of thrombus formation in weightlessness. The algorithm is based on early in-flight ultrasound testing to determine the flow characteristic of the left internal jugular vein and associated vasculature.
      NASA Working Group Recommendations
      The working group recommended several areas for further investigation to assess feasibility and potential to mitigate the risk of thrombosis in spaceflight:
      Improved detection capabilities to identify when a thrombus has formed in-flight, Pathophysiology/factors leading to thrombi formation during spaceflight, Countermeasures and treatment
      For more information on the working group meeting and a complete list of references, please see the Risk of Venous Thromboembolism (VTE) During Spaceflight Summary Report.
      Risk of Venous Thromboembolism (VTE) During Spaceflight Summary Report Share
      Details
      Last Updated Mar 14, 2025 EditorKim Lowe Related Terms
      Office of the Chief Health and Medical Officer (OCHMO) Astronauts General Human Health and Performance Humans in Space The Human Body in Space Keep Exploring Discover Related Topics
      OCHMO Independent Assessments
      Independent assessment plays a crucial role in NASA’s long-term success by addressing essential questions requiring rapid response to support further…
      Aerospace Medical Certification Standard
      This NASA Technical Standard provides medical requirements and clinical procedures designed to ensure crew health and safety and occupational longevity…
      Human Spaceflight Standards
      The Human Spaceflight & Aviation Standards Team continually works with programs to provide the best standards and implementation documentation to…
      Human Spaceflight and Aviation Standards
      The Human Spaceflight and Aviation Standards Team continuously works with subject matter experts and with each space flight program to…
      View the full article
    • By NASA
      6 min read
      Preparations for Next Moonwalk Simulations Underway (and Underwater)
      Risks Concept Risk is inherent in human spaceflight. However, specific risks can and should be understood, managed, and mitigated to reduce threats posed to astronauts. Risk management in the context of human spaceflight can be viewed as a trade-based system. The relevant evidence in life sciences, medicine, and engineering is tracked and evaluated to identify ways to minimize overall risk to the astronauts and to ensure mission success. The Human System Risk Board (HSRB) manages the process by which scientific evidence is utilized to establish and reassess the postures of the various risks to the Human System during all of the various types of existing or anticipated crewed missions. The HSRB operates as part of the Health and Medical Technical Authority of the Office of the Chief Health and Medical Officer of NASA via the JSC Chief Medical Officer.
      The HSRB approaches to human system risks is analogous to the approach the engineering profession takes with its Failure Mode and Effects Analysis in that a process is utilized to identify and address potential problems, or failures to reduce their likelihood and severity. In the context of risks to the human system, the HSRB considers eight missions which different in their destinations and durations (known as Design Reference Missions [DRM]) to further refine the context of the risks. With each DRM a likelihood and consequence are assigned to each risk which is adjusted scientific evidence is accumulated and understanding of the risk is enhanced, and mitigations become available or are advanced.
      Human System Risks This framework enables the principles of Continuous Risk Management and Risk Informed Decision Making (RIDM) to be applied in an ongoing fashion to the challenges posed by Human System Risks. Using this framework consistently across the 29 risks allows management to see where risks need additional research or technology development to be mitigated or monitored and for the identification of new risks and concerns. Further information on the implementation of the risk management process can be found in the following documents:
      Human System Risk Management Plan – JSC-66705 NASA Health and Medical Technical Authority (HMTA) Implementation – NPR 7120.11A NASA Space Flight Program and Project Management Requirements – NPR 7120.5 Human System Risk Board Management Office
      The HSRB Risk Management Office governs the execution of the Human System Risk management process in support of the HSRB. It is led by the HSRB Chair, who is also referred to as the Risk Manager.
      Risk Custodian Teams
      Along with the Human System Risk Manager, a team of risk custodians (a researcher, an operational researcher or physician, and an epidemiologist, who each have specific expertise) works together to understand and synthesize scientific and operational evidence in the context of spaceflight, identify and evaluate metrics for each risk in order to communicate the risk posture to the agency.
      Directed Acyclic Graphs 
      Summary
      The HSRB uses Directed Acyclic Graphs (DAG), a type of causal diagramming, as visual tools to create a shared understanding of the risks, improve communication among those stakeholders, and enable the creation of a composite risk network that is vetted by members of the NASA community and configuration managed (Antonsen et al., NASA/TM– 20220006812). The knowledge captured is the Human Health and Performance community’s knowledge about the causal flow of a human system risk, and the relationships that exist between the contributing factors to that risk.
      DAGs are:
      Intended to improve communication between: Managers and subject matter experts who need to discuss human system risks Subject matter experts in different disciplines where human system risks interact with one another in a potentially cumulative fashion Visual representations of known or suspected relationships Directed – the relationship flows in one direction between any two nodes Acyclic – cycles in the graph are not allowed Example of a Directed Acyclic Graph. This is a simplified illustration of how and the individual, the crew, and the system contribute to the likelihood of successful task performance in a mission. Individual readiness is affected by many of the health and performance-oriented risks followed by the HSRB, but the readiness of any individual crew is complemented by the team and the system that the crew works within. Failures of task performance may lead to loss of mission objectives if severe.NASA View Larger (Example of a Directed Acyclic Graph) Image
      Details
      At NASA, the Human System Risks have historically been conceptualized as deriving from five Hazards present in the spaceflight environment. These are: altered gravity, isolation and confinement, radiation, a hostile closed environment, and distance from Earth. These Hazards are aspects of the spaceflight environment that are encountered when someone is launched into space and therefore are the starting point for causal diagramming of spaceflight-related risk issues for the HSRB.
      These Hazards are often interpreted in relation to physiologic changes that occur in humans as a result of the exposure; however, interaction between human crew (behavioral health and performance), which may be degraded due to the spaceflight environment – and the vehicle and mission systems that the crew must operate – can also be influenced by these Hazards.
      Each Human System Risk DAG is intended to show the causal flow of risk from Hazards to Mission Level Outcomes. As such, the structure of each DAG starts with at least one Hazard and ends with at least one of the pre-defined Mission Level Outcomes. In between are the nodes and edges of the causal flow diagrams that are relevant to the Risk under consideration. These are called ‘contributing factors’ in the HSRB terminology, and include countermeasures, medical conditions, and other Human System Risks. A graph data structure is composed of a set of vertices (nodes), and a set of edges (links). Each edge represents a relationship between two nodes. There can be two types of relationships between nodes: directed and undirected. For example, if an edge exists between two nodes A and B and the edge is undirected, it is represented as A–B, (no arrow). If the edge were directed, for example from A to B, then this is represented with an arrow (A->B). Each directed arrow connecting one node to another on a DAG indicates a claim of causality. A directed graph can potentially contain a cycle, meaning that, from a specific node, there exists a path that would eventually return to that node. A directed graph that has no cycles is known as acyclic. Thus, a graph with directed links and no cycles is a DAG.  DAGs are a type of network diagram that represent causality in a visual format.
      DAGs are updated with the regular Human System Risk updates generally every 1-2 years. Approved DAGs can be found in the NASA/TP 20220015709 below or broken down under each Human System Risk.
      Documents
      Directed Acyclic Graph Guidance Documentation – NASA/TM 20220006812 Directed Acyclic Graphs: A Tool for Understanding the NASA Human Spaceflight System Risks – NASA/TP 20220015709 Publications
      npj Microgravity – Causal diagramming for assessing human
      system risk in spaceflight
      Apr 22, 2024
      PDF (3.09 MB)
      npj Microgravity –
      Levels of evidence for human system risk
      evaluation
      Apr 22, 2024
      PDF (2.47 MB)
      npj Microgravity –
      Updates to the NASA human system risk management process
      for space exploration
      Apr 22, 2024
      PDF (2.24 MB)
      Points of Contact
      Mary Van Baalen
      Dan Buckland
      Bob Scully
      Kim Lowe
      Human System Risks Share
      Details
      Last Updated Mar 11, 2025 EditorRobert E. LewisLocationJohnson Space Center Related Terms
      Human Health and Performance Human System Risks Explore More
      1 min read Concern of Venous Thromboembolism
      Article 31 mins ago 1 min read Risk of Acute and Chronic Carbon Dioxide Exposure
      Article 30 mins ago 1 min read Risk of Adverse Cognitive or Behavioral Conditions and Psychiatric Disorders
      Article 30 mins ago Keep Exploring Discover More Topics From NASA
      Humans In Space
      Missions
      International Space Station
      Solar System
      View the full article
  • Check out these Videos

×
×
  • Create New...