Risk of Venous Thromboembolism During Spaceflight

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.

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.

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:

1. Alterations in blood flow (i.e., stasis),
2. Vascular endothelial injury/changes, and/or,
3. 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.

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.

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.

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.

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Sols 4479-4480: What IS That Lumpy, Bumpy Rock?

Written by Ashley Stroupe, Mission Operations Engineer at NASA’s Jet Propulsion Laboratory

Earth planning date: Wednesday, March 12, 2025

The days are getting shorter and colder for Curiosity as we head into winter. So our rover is sleeping in a bit before waking up to a busy plan. Today I served as the Engineering Uplink Lead, managing the engineering side of the plan to support all the science activities. 

We are seeing a lot of rocks with different, interesting textures, so Curiosity’s day begins with a lot of targeted imaging of this interesting area. The two rocks right in front of us (see image above) are different from anything that we have looked at before on the mission, so we are eager to know what they are. We are taking Mastcam images of “Manzana Creek” and “Palo Comado,” two of these interestingly textured rocks, and also of an area named “Vincent Gap,” where the rover disturbed some bedrock and exposed some regolith by driving over it in the prior plan. ChemCam is making a LIBS observation of a target called “Sturtevant Falls,” which is a nodule on the left-hand block in our workspace (on which we are later doing some contact science). ChemCam is also taking a long-distance RMI image in the direction of the potential boxworks formation (large veins), which is an area we will be exploring close-up in the future. There are also a Navcam dust devil movie and suprahorzion movie. Check out this article from November for more information on the boxwork formations.

After a nap, Curiosity wakes up to get in her arm exercise. I do not envy the Arm Rover Planner today (OK, maybe a little bit) in dealing with this very challenging workspace. The rock of interest (the left-hand rock in the above image) has jagged, vertical surfaces and a lot of crazy rough texture. Examining this rock is even more challenging because our primary targets are on the left side of the rock, rather than the side that is facing the rover. We are looking at two different targets, “Stunt Ranch,” which is a nodule on the rock, and “Pacifico Mountain,” which is the left-side face of the rock, with MAHLI and also doing a long APXS integration on Stunt Ranch. After the arm work, Curiosity is tucking herself in for the night by stowing the arm. 

The next morning, after again getting to sleep in a bit, Curiosity will make some more targeted observations, starting with another dust-devil survey. ChemCam will make a LIBS observation of “Switzer Falls,” which is a target on the right-hand rock in the workspace (and in the image), an RMI of “Colby Canyon,” a soft sediment deformation, and “Gould,” which is another target on the boxworks formation. Lastly, Mastcam takes a look at “Potrero John,” yet another interestingly textured rock.

Curiosity will then be ready to drive away. Today’s drive is on slightly better terrain that we have been seeing recently, with fewer large and pointy rocks. Though, the mobility rover planners still have to be careful about picking the safest path through. We’re heading about 25 meters (about 82 feet) to another rock target named “Humber Park,” where we hope to do additional contact science. After the drive, we have our standard set of post-drive imaging, a Mastcam solar tau, and then an early-morning Navcam cloud observation.

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Career Spotlight: Engineer (Ages 14-18)

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Career Spotlight: Engineer (Ages 14-18)

What does an engineer do?

An engineer applies scientific principles to design, build, and test machines, systems, or structures to meet specific needs. They follow the steps of the engineering design process to ensure their designs work as planned while meeting a variety of requirements, including size, weight, safety, and cost.

NASA hires several types of engineers to help tackle a range of missions. Whether it’s creating quieter supersonic aircraft, building powerful space telescopes to study the cosmos, or developing spacecraft to take humanity to the Moon, Mars, and beyond, NASA pushes the boundaries of engineering, giving us greater knowledge of our universe and a better quality of life here on Earth.

What are the different types of engineering?

• Aerospace engineer: Applies engineering principles to design hardware and software specific to flight systems for use in Earth’s atmosphere or in space.

• Chemical engineer: Uses chemistry to conduct research or develop new materials.

• Civil engineer: Designs human-made structures, such as launch pads, test stands, or a future lunar base.

• Electrical engineer: Specializes in the design and testing of electronics such as computers, motors, and navigation systems.

• Mechanical engineer: Designs and tests mechanical equipment and systems, such as rocket engines, aircraft frames, and astronaut tools.

How can I become an engineer?

High school is the perfect time to build a solid foundation of science and math skills through challenging academic courses as well as extracurricular activities, such as science clubs, robotics teams, or STEM camps in your area. You can also start researching what type of engineering is right for you, what colleges offer those engineering programs, and what you need to do to apply to those colleges.

Engineering roles typically require at least a bachelor’s degree.

How can I start preparing today to become an engineer?

Looking for some engineering experiences you can try right away? NASA STEM offers hands-on activities for a variety of ages and skill levels. Engineering includes iteration – repeating something and making changes in an effort to learn more and improve the process or the design. When you try these activities, make a small change each time you repeat the process, and see whether your design improves.

NASA’s student challenges and competitions give teams the opportunity to gain authentic experience by taking on some of the technological challenges of spaceflight and aviation.

NASA also offers paid internships for U.S. citizens aged 16 and up. Interns work on real projects with the guidance of a NASA mentor. Internship sessions are held each year in spring, summer, and fall; visit NASA’s Internships website to learn about important deadlines and current opportunities.

Advice from NASA engineers

“A lot of people think that just because they are more artistic or more creative, that they’re not cut out for STEM fields. But in all honesty, engineers and scientists have to be creative and have to be somewhat artistic to be able to come up with new ideas and see how they can solve the problems in the world around them.” – Sam Zauber, wind tunnel test engineer

“Students today have so many opportunities in the STEM area that are available to them. See what you like. See what you’re good at. See what you don’t like. Learn all there is to learn, and then you can really choose your own path. As long as you have the aptitude and the willingness to learn, you’re already there.”

Heather Oravec

Aerospace and Geotechnical Research Engineer

“Joining clubs and participating in activities that pique your interests is a great way to develop soft skills – like leadership, communication, and the ability to work with others – which will prepare you for future career opportunities.” – Estela Buchmann, navigation, guidance, and control systems engineer

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NASA Super Pressure Balloons Return to New Zealand for Test Flights

NASA’s Scientific Balloon Program has returned to Wānaka, New Zealand, for two scheduled flights to test and qualify the agency’s super pressure balloon technology. These stadium-sized, heavy-lift balloons will travel the Southern Hemisphere’s mid-latitudes for planned missions of 100 days or more. 

Launch operations are scheduled to begin in late March from Wānaka Airport, NASA’s dedicated launch site for mid-latitude, ultra long-duration balloon missions.  

“We are very excited to return to New Zealand for this campaign to officially flight qualify the balloon vehicle for future science investigations,” said Gabriel Garde, chief of NASA’s Balloon Program Office at the agency’s Wallops Flight Facility in Virginia. “Our dedicated team both in the field and at home has spent years in preparation for this opportunity, and it has been through their hard work, fortitude, and passion that we are back and fully ready for the upcoming campaign.” 

While the primary flight objective is to test and qualify the super pressure balloon technology, the flights will also host science missions and technology demonstrations. The High-altitude Interferometer Wind Observation (HIWIND), led by High Altitude Observatory, National Center for Atmospheric Research in Boulder, Colorado, will fly as a mission of opportunity on the first flight. The HIWIND payload will measure neutral wind in the part of Earth’s atmosphere called the thermosphere. Understanding these winds will help scientists predict changes in the ionosphere, which can affect communication and navigation systems. The second flight will support several piggyback missions of opportunity, or smaller payloads, including: 

• Compact Multichannel Imaging Camera (CoMIC), led by University of Massachusetts Lowell, will study and measure how Earth’s atmosphere scatters light at high altitudes and will measure airglow, specifically the red and green emissions.  
• High-altitude Infrasound from Geophysical Sources (HIGS), led by NASA’s Jet Propulsion Laboratory and Sandia National Laboratories, will measure atmospheric pressure to collect signals of geophysical events on Earth such as earthquakes and volcanic eruptions. These signals will help NASA as it develops the ability to measure seismic activity on Venus from high-altitude balloons.   
• Measuring Ocean Acoustics North of Antarctica (MOANA), led by Sandia National Laboratories and Swedish Institute of Space Physics, aims to capture sound waves in Earth’s stratosphere with frequencies below the limit of human hearing.
• NASA’s Balloon Program Office at the agency’s Wallops Flight Facility is leading two technology demonstrations on the flight. The INterim Dynamics Instrumentation for Gondolas (INDIGO) is a data recorder meant to measure the shock of the gondola during the launch, termination, and landing phases of flight. The Sensor Package for Attitude, Rotation, and Relative Observable Winds – 7 (SPARROW-7), will demonstrate relative wind measurements using an ultrasonic device designed for the balloon float environment that measures wind speed and direction.

NASA’s 18.8-million-cubic-foot (532,000-cubic-meter) helium-filled super pressure balloon, when fully inflated, is roughly the size of Forsyth-Barr Stadium in Dunedin, New Zealand, which has a seating capacity of more than 35,000. The balloon will float at an altitude of around 110,000 feet (33.5 kilometers), more than twice the altitude of a commercial airplane. Its flight path is determined by the speed and direction of wind at its float altitude.  

The balloon is a closed system design to prevent gas release. It offers greater stability at float altitude with minimum altitude fluctuations during the day to night cycle compared to a zero pressure balloon. This capability will enable future missions to affordably access the near-space environment for long-duration science and technology research from the Southern Hemisphere’s mid-latitudes, including nighttime observations. 

The public is encouraged to follow real-time tracking of the balloons’ paths as they circle the globe on the agency’s Columbia Scientific Balloon Facility website. Launch and tracking information will be shared across NASA’s social media platforms and the NASA Wallops blog.

NASA’s return to Wānaka marks the sixth super pressure balloon campaign held in New Zealand since the agency began balloon operations there in 2015. The launches are conducted in collaboration with the Queenstown Airport Corporation, Queenstown Lake District Council, New Zealand Space Agency, and Airways New Zealand.  

“We are especially grateful to our local hosts, partners, and collaborators who have been with us from the beginning and are critical to the success of these missions and this campaign,” said Garde. 

NASA’s Wallops Flight Facility in Virginia manages the agency’s scientific balloon flight program with 10 to 16 flights each year from launch sites worldwide. Peraton, which operates NASA’s Columbia Scientific Balloon Facility in Palestine, Texas, provides mission planning, sustaining engineering services, and field operations for NASA’s scientific balloon program. The Columbia team has launched more than 1,700 scientific balloons over some 40 years of operations. NASA’s balloons are fabricated by Aerostar. The NASA Scientific Balloon Program is funded by the NASA Headquarters Science Mission Directorate Astrophysics Division.  

For more information on NASA’s Scientific Balloon Program, visit:

www.nasa.gov/scientificballoons.

By Olivia Littleton

NASA’s Wallops Flight Facility, Wallops Island, Va.

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NASA Expertise Helps Record all the Buzz

Airplane manufacturers running noise tests on new aircraft now have a much cheaper option than traditional wired microphone arrays. It’s also sensitive enough to help farmers with pest problems. A commercial wireless microphone array recently created with help from NASA can locate crop-threatening insects by listening for the sounds they make in fields. 

Since releasing its first commercial product in 2017, a sensor for wind tunnel testing developed with extensive help from NASA (Spinoff 2020), Interdisciplinary Consulting Corporation (IC2) has doubled its staff and moved to a larger lab and office space to produce its new WirelessArray product. Interested in making its own flight tests more affordable, NASA’s Langley Research Center in Hampton, Virginia, supported this project with Small Business Innovation Research contracts and expert consulting.

Airplanes go through noise testing and require certification that they don’t exceed the noise level set for their body type by the Federal Aviation Administration. When an airplane flies directly overhead, the array collects noise data to build a two-dimensional map of the sound pressure and its source. A custom software package translates that information for the end user.

For previous NASA noise testing, multiple semi-trucks hauled all the sensors, wires, power generators, racks of servers, and other equipment required for one flight test. The setup and teardown took six people three days. By contrast, two people can pack the WirelessArray into a minivan and set it up in a day. 

IC2 is working with an entomologist to use acoustic data to listen for high-frequency insect sounds in agricultural settings. Discovering where insects feed on crops will make it possible for farmers to intervene before they do too much damage while limiting pesticide use to those areas. Whether it’s helping planes in the sky meet noise requirements or keeping harmful insects away from crops, NASA technology is finding sound-based solutions for the benefit of all. 

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