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Thawing permafrost in the Arctic is already unleashing methane and carbon dioxide to the atmosphere, exacerbating global temperature rise. As well adding to the climate crisis, this ground, which has been frozen for thousands of years, is becoming unstable and causing serious issues for local communities. For the first time, data from the Copernicus Sentinel-1 and Sentinel-2 missions along with artificial intelligence have been used to offer a complete overview of the Arctic to identify communities and infrastructure that will be at risk over the next 30 years.

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    • By NASA
      NASA science and American industry have worked hand-in-hand for more than 60 years, transforming novel technologies created with NASA research into commercial products like cochlear implants, memory-foam mattresses, and more. Now, a NASA-funded device for probing the interior of storm systems has been made a key component of commercial weather satellites.
      The novel atmospheric sounder was originally developed for NASA’s TROPICS (short for Time-Resolved Observations of Precipitation structure and storm Intensity with a Constellation of SmallSats), which launched in 2023. Boston-based weather technology company Tomorrow.io integrated the same instrument design into some of its satellites.
      NASA’s TROPICS instrument. TROPICS pioneered a novel, compact atmospheric sound now flying aboard a fleet of commercial small satellites created by the weather technology company Tomorrow.io.Credit: Blue Canyon Technologies Atmospheric sounders allow researchers to gather data describing humidity, temperature, and wind speed — important factors for weather forecasting and atmospheric analysis. From low-Earth orbit, these devices help make air travel safer, shipping more efficient, and severe weather warnings more reliable.
      Novel tools for Observing Storm Systems
      In the early 2000s, meteorologists and atmospheric chemists were eager to find a new science tool that could peer deep inside storm systems and do so multiple times a day. At the same time, CubeSat constellations (groupings of satellites each no larger than a shoebox) were emerging as promising, low-cost platforms for increasing the frequency with which individual sensors could pass over fast-changing storms, which improves the accuracy of weather models.
      The challenge was to create an instrument small enough to fit aboard a satellite the size of a toaster, yet powerful enough to observe the innermost mechanisms of storm development. Preparing these technologies required years of careful development that was primarily supported by NASA’s Earth Science Division.
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      With a 2010 award from NASA’s Earth Science Technology Office (ESTO), Blackwell’s team created an ultra-compact microwave receiver, a component that can sense the microwave radiation within the interior of storms.
      The Lincoln Lab receiver weighed about a pound and took up less space than a hockey puck. This innovation paved the way for a complete atmospheric sounder instrument small enough to fly aboard a CubeSat. “The hardest part was figuring out how to make a compact back-end to this radiometer,” Blackwell said. “So without ESTO, this would not have happened. That initial grant was critical.”
      In 2023, that atmospheric sounder was sent into space aboard four TROPICS CubeSats, which have been collecting torrents of data on the interior of severe storms around the world.
      Transition to Industry
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      In 2022, the company worked with Blackwell to adapt his team’s design into a CubeSat platform about twice the size of the one used for TROPICS. A bigger platform, Blackwell explained, meant they could bolster the sensor’s capabilities.
      “When we first started conceptualizing this, the 3-unit CubeSat was the only game in town. Now we’re using a 6-unit CubeSat, so we have room for onboard calibration,” which improves the accuracy and reliability of gathered data, Blackwell said.
      Tomorrow.io’s first atmospheric sounders, Tomorrow-S1 and Tomorrow-S2, launched in 2024. By the end of 2025, the company plans to have a full constellation of atmospheric sounders in orbit. The company also has two radar instruments that were launched in 2023 and were influenced by NASA’s RainCube instrument — the first CubeSat equipped with an active precipitation radar.
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      Having access to an atmospheric sounder that had already flown in space and had more than 10 years of testing was extremely useful as Tomorrow.io planned its fleet. “It would not have been possible to do this nearly as quickly or nearly as affordably had NASA not paved the way,” said Jennifer Splaingard, Tomorrow.io’s senior vice president for space and sensors.
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      The relationship between NASA and industry is symbiotic. NASA and its grantees can drive innovation and test new tools, equipping American businesses with novel technologies they may otherwise be unable to develop on their own. In exchange, NASA gains access to low-cost data sets that can supplement information gathered through its larger science missions.
      Tomorrow.io was among eight companies selected by NASA’s Commercial SmallSat Data Acquisition (CSDA) program in September 2024 to equip NASA with data that will help improve weather forecasting models. “It really is a success story of technology transfer. It’s that sweet spot, where the government partners with tech companies to really take an idea, a proven concept, and run with it,” Splaingard said.
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      NASA’s Goddard Space Flight Center, Greenbelt, Md.
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      Last Updated Sep 02, 2025 Related Terms
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    • By NASA
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      Cloud cover can keep optical instruments on satellites from clearly capturing Earth’s surface. Still in testing, JPL’s Dynamic Targeting uses AI to avoid imaging clouds, yielding a higher proportion of usable data, and to focus on phenomena like this 2015 volcanic eruption in Indonesia Landsat 8 captured.NASA/USGS A technology called Dynamic Targeting could enable spacecraft to decide, autonomously and within seconds, where to best make science observations from orbit.
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      This graphic shows how JPL’s Dynamic Targeting uses a lookahead sensor to see what’s on a satellite’s upcoming path. Onboard algorithms process the sensor’s data, identifying clouds to avoid and targets of interest for closer observation as the satellite passes overhead.NASA/JPL-Caltech “The idea is to make the spacecraft act more like a human: Instead of just seeing data, it’s thinking about what the data shows and how to respond,” says Steve Chien, a technical fellow in AI at JPL and principal investigator for the Dynamic Targeting project. “When a human sees a picture of trees burning, they understand it may indicate a forest fire, not just a collection of red and orange pixels. We’re trying to make the spacecraft have the ability to say, ‘That’s a fire,’ and then focus its sensors on the fire.”
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      How Dynamic Targeting Works
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      Since CogniSAT-6 lacks an imager dedicated to looking ahead, the spacecraft tilts forward 40 to 50 degrees to point its optical sensor, a camera that sees both visible and near-infrared light. Once look-ahead imagery has been acquired, Dynamic Targeting’s advanced algorithm, trained to identify clouds, analyzes it. Based on that analysis, the Dynamic Targeting planning software determines where to point the sensor for cloud-free views. Meanwhile, the satellite tilts back toward nadir (looking directly below the spacecraft) and snaps the planned imagery, capturing only the ground.
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      What’s Next
      With the cloud-avoidance capability now proven, the next test will be hunting for storms and severe weather — essentially targeting clouds instead of avoiding them. Another test will be to search for thermal anomalies like wildfires and volcanic eruptions. The JPL team developed unique algorithms for each application.
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      Jet Propulsion Laboratory, Pasadena, Calif.
      626-314-4928
      melissa.pamer@jpl.nasa.gov
      2025-094
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      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
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      Last Updated Mar 14, 2025 EditorKim Lowe Related Terms
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    • By NASA
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      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
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      Last Updated Mar 11, 2025 EditorRobert E. LewisLocationJohnson Space Center Related Terms
      Human Health and Performance Human System Risks Explore More
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      Lightning strikes the Launch Pad 39B protection system as preparations for launch of NASA’s Space Launch System (SLS) rocket with the Orion spacecraft aboard continue, Saturday, Aug. 27, 2022, at NASA’s Kennedy Space Center in Florida. NASA’s Artemis I flight test is the first integrated test of the agency’s deep space exploration systems: the Orion spacecraft, SLS rocket, and supporting ground systems. Launch of the uncrewed flight test is targeted for no earlier than Aug. 29 at 8:33 a.m. ET. Photo Credit: (NASA/Bill Ingalls) Directed Acyclic Graph Files
      + DAG File Information (HSRB Home Page)
      + Electrical Shock Risk DAG and Narrative (PDF)
      + Electrical Shock Risk DAG Code (TXT)
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