Diving Into Human Spaceflight Safety with NASA Johnson’s Craig Shannon

Diving Into Human Spaceflight Safety with NASA Johnson’s Craig Shannon

Growing up in Houston, Craig Shannon was always inspired by NASA and the spirit of exploration the agency represents. Yet it was a passion for scuba diving that unexpectedly led to his more than 23-year career at NASA’s Johnson Space Center.

Shannon became a certified diver and scuba instructor while earning his bachelor’s degree in communications from Stephen F. Austin State University. He happened to meet divers from NASA’s Neutral Buoyancy Laboratory (NBL) at a local environmental cleanup event during his senior year. “The encounter planted a seed,” he said.

A man wearing a black wetsuit floats with his head above water in a large swimming pool.
Craig Shannon during a dive in the Neutral Buoyancy Laboratory pool at NASA’s Johnson Space Center.
Image courtesy of Craig Shannon

Shannon was hired as an NBL diver shortly after graduation, launching what would become a 19-year career in dive operations. He progressed through a variety of roles – from utility diver, instructor, and training officer, to dive operations lead, training group lead, and ultimately, dive operations manager. “Each role deepened my understanding of operational excellence, safety, and leadership in high-performance environments,” he said. Shannon added that becoming the dive operations manager was one of the defining points of his career. “I had the privilege of leading an exceptional team and contributing directly to astronaut training and operational excellence.”

Seeking new challenges and opportunities for professional growth, Shannon transitioned to a test safety officer position at Johnson for about four years, expanding his knowledge of technical risk management in different environments. He returned to the NBL in 2025, this time as a safety officer. In that role, Shannon works to protect employees’ well-being and the facility’s operational integrity. His responsibilities are a mix of proactive safety initiatives – such as facility inspections, safety training, and communication – and incident response, which involves investigating mishaps and close calls and developing corrective action plans to prevent recurrence. He also serves as an internal technical consultant, fielding safety-related questions from employees and visitors and providing guidance that complies with Occupational Safety and Health Administration and NASA safety standards.

“I work across functions with operations, engineering, medical, and training teams to integrate safety into all daily processes and long-term planning,” he said. “It brings full circle my commitment to the safety and success of human spaceflight training.”

A man in a blue polo shirt inspects the spacesuit worn by another man.
Former NASA astronaut Mike Massimino helps Craig Shannon suit up for a suited test dive in the Neutral Buoyancy Laboratory pool.
Image courtesy of Craig Shannon

Shannon acknowledged that not having an engineering degree has made work more challenging at times, but it has not hindered his advancement. “I’ve earned key positions by committing myself to continuous learning, gaining in-depth knowledge of the technical areas I work in, and consistently demonstrating dedication to both my employers and my career,” he said. “My path has required hard work, adaptability, and a proactive approach to professional growth, which I view as strengths that have allowed me to contribute meaningfully in a highly technical setting.”

Shannon has also learned the importance of embracing change. “Change isn’t always easy, but it’s often where the most learning and development happen,” he said. “Whether it was stepping into leadership for the first time, shifting into a new field, or returning to a familiar place with a new purpose, each transition brought growth I never could have anticipated.” He added that patience, accountability, and empathy are important leadership qualities that help build stronger, more resilient teams.

While Shannon takes pride in his work, he said his family is his greatest achievement. “I’m most proud of raising three amazing children with my wife, Kimberley. They have been my grounding force and greatest inspiration,” he said.

A family of five - a man, wife, and their three children - stand on the sand of a Florida beach on a sunny day.
Craig Shannon, his wife Kimberley, and their three children enjoy family time at the beach in Florida.
Image courtesy of Craig Shannon

He is also the proud co-owner of a local scuba diving company, which allows him to combine his love for diving, travel, and community. “I’ve had the privilege of leading dive trips around the world with groups of amazing people—sharing unforgettable underwater experiences and fostering a strong, adventurous dive community,” he said. “It’s a way for me to stay connected to the roots of my diving career and continue exploring the world through the lens of curiosity and connection.”

He encourages the next generation to find something they are passionate about. “It’s important to be genuinely excited about what you do and to face the challenges ahead with determination and curiosity,” he said. “That energy, paired with a willingness to adapt and grow, has carried me through each phase of my career. Challenges will come, but how you meet them defines your path.”

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Linda E. Grimm

Reaching the Precipice in Angola 

Reaching the Precipice in Angola 

This satellite image centers on the serrated edge of the Huila plateau in Angola. The sheer cliff wall forms a rough C shape and is highlighted by dark shadows and a band of green vegetation. The lowlands to the left are tan-colored arid coastal plains, and the more-temperate plateau on the right side is greener.
June 19-20, 2025

In southwestern Angola, an expanse of coastal plains comes to an abrupt end at a natural barrier. The Huíla plateau soars above the lowlands to elevations of around 2,300 meters (7,500 feet). The sharp transition results in dramatic landscapes and a sudden change from an arid environment to more-temperate climes.  

The serrated edge of the Huíla plateau zigzags through this image, which is a mosaic of scenes acquired on June 19 and 20, 2025, with the OLI-2 (Operational Land Imager-2) and OLI on the Landsat 9 and Landsat 8 satellites, respectively. Areas around the plateau’s edges appear green with vegetation. But the landscape tends to look much browner by late September, at the end of the region’s dry season, during which almost no rain falls.  

This topography is part of the Great Escarpment of southern Africa, a 5,000-kilometer-long feature running roughly parallel to the continent’s edge. From Angola, it extends south through Namibia, across South Africa, and then northeast into Zimbabwe and Mozambique. The image below, acquired with the VIIRS (Visible Infrared Imaging Radiometer Suite) on the Suomi NPP satellite, shows a longer segment of the escarpment in Angola.  

A satellite image of southwestern Angola shows light-colored coastal desert to the left and a darker plateau to the right. These are separated by a jagged boundary tinged with green, part of the Great Escarpment of southern Africa. The Atlantic Ocean, mostly cloud-covered, runs along the left edge of the image.
June 20, 2025

Scientists believe the escarpment formed after the breakup of the supercontinent Gondwana in the Jurassic period. Since then, erosion has worn away at the continental margin such that the escarpment now sits 50 to 200 kilometers (30 to 120 miles) back from the coast.   

This Angolan section of the escarpment features dizzying, yet beautiful, landscapes. Tundavala Gap, a gouge eroded into the cliff line (below), is one of the most iconic with its well-framed view of the plains below. The precipice also presents a substantial obstacle to transportation. A stretch of the Namibe-Lubango Road overcomes this challenge with a series of scenic hairpin turns climbing to Serra da Leba pass near the town of Leba.  

Sheer cliff walls on the right and left sides of this photograph make a V shape in the foreground. Some light green shrubs grow from cracks in the rock. The ground visible in the opening between the cliffs is far below.
March 11, 2014

Lubango, one of Angola’s largest cities, occupies a valley on the Huíla plateau. In addition to its remarkable natural surroundings, the city boasts a diverse mix of cultures, striking architecture, and a wide variety of locally produced foods.  

NASA Earth Observatory images by Wanmei Liang, using Landsat data from the U.S. Geological Survey, and VIIRS data from NASA EOSDIS LANCEGIBS/Worldview, the Suomi National Polar-orbiting Partnership, and the Joint Polar Satellite System (JPSS). Photo of Tundavala Gap © jbdodane.com. Story by Lindsey Doermann. 

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Expedition 74 Gears Up for First Spacewalk of 2026

Expedition 74 Gears Up for First Spacewalk of 2026

At center, JAXA (Japan Aerospace Exploration Agency) astronaut and Expedition 74 Flight Engineer Kimiya Yui assists NASA astronauts Zena Cardman (left) and Mike Fincke (right), the station’s flight engineer and commander respectively, during spacesuit checks inside the International Space Station’s Quest airlock.
At center, JAXA (Japan Aerospace Exploration Agency) astronaut Kimiya Yui assists NASA astronauts Zena Cardman (left) and Mike Fincke (right) during spacesuit checks inside the International Space Station’s Quest airlock.
NASA

The Expedition 74 crew is gearing up for the first spacewalk of 2026 this week that will see two astronauts prepare the International Space Station for a new set of roll-out solar arrays. The orbital residents also had time on Monday to conduct microgravity research, pack a U.S. cargo craft, and maintain communications and life support systems.

NASA astronauts Mike Fincke and Zena Cardman are scheduled to exit the orbital outpost’s Quest airlock at 8 a.m. EST on Thursday for a six-and-a-half-hour spacewalk. The duo will install a modification kit and route cables setting up the station’s port side truss structure for a new roll-out solar array that will be delivered on an upcoming cargo mission. Other tasks include installing jumper cables, photographing station hardware, and swabbing external station surfaces to collect potential microorganism samples. Managers will preview Thursday’s spacewalk and a second spacewalk scheduled for Jan. 15 on NASA’s YouTube channel beginning at 2 p.m. on Tuesday.

Fincke and Cardman were joined by Chris Williams of NASA and Kimiya Yui of JAXA (Japan Aerospace Exploration Agency) on Monday reviewing Thursday’s spacewalk procedures and confirming their readiness with mission controllers on the ground. Williams and Yui will assist the duo in and out of their spacesuits, pressurize and depressurize the Quest airlock, and monitor the spacewalkers as they work on their tasks in the external environment of space. Fincke and Cardman also checked out their spacesuit emergency jetpacks that enable a spacewalker to safely maneuver back to the orbital outpost in the unlikely event they become untethered.

Yui and Williams also partnered together at the end of the day on Monday installing cassettes containing protein crystal samples inside the Advanced Sample Experiment Processor-4 and photographing the research activities. The science work took place in the Destiny laboratory module and was done in support of the Pharmaceutical In-Space Laboratory set of experiments that is exploring developing and manufacturing medicines in space.

Earlier, Yui worked inside SpaceX Dragon cargo spacecraft transferring items as it nears its departure planned for later this month. Williams had begun his day with Cardman inside the Tranquility module packing hardware for stowage inside the NanoRacks Bishop airlock.

Roscosmos Flight Engineer Oleg Platonov started his day wearing an acoustic monitor around his neck that recorded him as he exhaled forcefully for a study researching lung function in weightlessness. Afterward, he inventoried medical kits ensuring pharmaceuticals and hardware were up to date. Cosmonauts Sergey Kud-Sverchkov and Sergei Mikaev familiarized themselves with the same lung function study Platonov participated in and learned about the acoustic characteristics of the trachea, monitoring the respiratory system, and early diagnosis of potential space-caused breathing disorders.

Earlier, Mikaev worked inside the Zarya module searching for and documenting the location of a variety of hardware. Kud-Sverchkov also worked inside Zarya inventorying video hardware before replacing filters and cleaning life support gear in the Rassvet module.

Learn more about station activities by following the space station blog, @space_station on X, as well as the ISS Facebook and ISS Instagram accounts.

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Mark A. Garcia

NASA’s IXPE Measures White Dwarf Star for First Time

NASA’s IXPE Measures White Dwarf Star for First Time

This artist’s concept depicts a smaller white dwarf star pulling material from a larger star, right, into an accretion disk. Earlier this year, scientists used NASA’s IXPE (Imaging X-ray Polarization Explorer) to study a white dwarf star and its X-ray polarization.
This artist’s concept depicts a smaller white dwarf star pulling material from a larger star, right, into an accretion disk. Earlier this year, scientists used NASA’s IXPE (Imaging X-ray Polarization Explorer) to study a white dwarf star and its X-ray polarization.
MIT/Jose-Luis Olivares

By Michael Allen 
 
For the first time, scientists have used NASA’s IXPE (Imaging X-ray Polarization Explorer) to study a white dwarf star. Using IXPE’s unique X-ray polarization capability, astronomers examined a star called the intermediate polar EX Hydrae, unlocking the geometry of energetic binary systems. 
 
In 2024, IXPE spent nearly one week focused on EX Hydrae, a white dwarf star system located in the constellation Hydra, approximately 200 light-years from Earth. A paper about the results published in the Astrophysical Journal. Astrophysics research scientists based at the Massachusetts Institute of Technology in Cambridge led the study, along with co-authors at the University of Iowa, East Tennessee State University, University of Liége, and Embry Riddle Aeronautical University. 
 
A white dwarf star occurs after a star runs out of hydrogen fuel to fuse in its core but is not massive enough to explode as core-collapse supernovae. What remains is very dense, roughly the same diameter as Earth with as much mass as our Sun.  
 
EX Hydrae is in a binary system with a main sequence companion star, from which gas is continuously falling onto the white dwarf. How exactly the white dwarf is accumulating, or accreting, this matter and where it arrives on the white dwarf depends on the strength of the white dwarf star’s magnetic field. 
 
In the case of EX Hydrae, its magnetic field is not strong enough to focus matter completely at the star’s poles. But, it is still rapidly adding mass to the accretion disk, earning the classification “intermediate polars. 

By Michael Allen

For the first time, scientists have used NASA’s IXPE (Imaging X-ray Polarization Explorer) to study a white dwarf star. Using IXPE’s unique X-ray polarization capability, astronomers examined a star called the intermediate polar EX Hydrae, unlocking the geometry of energetic binary systems.

In 2024, IXPE spent nearly one week focused on EX Hydrae, a white dwarf star system located in the constellation Hydra, approximately 200 light-years from Earth. A paper about the results published in the Astrophysical Journal. Astrophysics research scientists based at the Massachusetts Institute of Technology in Cambridge led the study, along with co-authors at the University of Iowa, East Tennessee State University, University of Liége, and Embry Riddle Aeronautical University.

A white dwarf star occurs after a star runs out of hydrogen fuel to fuse in its core but is not massive enough to explode as core-collapse supernovae. What remains is very dense, roughly the same diameter as Earth with as much mass as our Sun.

EX Hydrae is in a binary system with a main sequence companion star, from which gas is continuously falling onto the white dwarf. How exactly the white dwarf is accumulating, or accreting, this matter and where it arrives on the white dwarf depends on the strength of the white dwarf star’s magnetic field.

In the case of EX Hydrae, its magnetic field is not strong enough to focus matter completely at the star’s poles. But, it is still rapidly adding mass to the accretion disk, earning the classification “intermediate polars.

In an intermediate polar system, material forms an accretion disk while also being pulled towards its magnetic poles. During this phenomenon, matter reaches tens of millions of degrees Fahrenheit, bouncing off other material bound to the white dwarf star, creating large columns of gas that emit high-energy X-rays – a cosmic situation perfect for IXPE to study.

“NASA IXPE’s one-of-a-kind polarimetry capability allowed us to measure the height of the accreting column from the white dwarf star to be almost 2,000 miles high – without as many assumptions required as past calculations,” said Sean Gunderson, MIT scientist and lead author on the paper. “The X-rays we observed likely scattered off the white dwarf’s surface itself. These features are far smaller than we could hope to image directly and clearly show the power of polarimetry to ‘see’ these sources in detail never before possible.”

Information from IXPE’s polarization data of EX Hydrae will help scientists understand other highly energetic binary systems.

More about IXPE 

 The IXPE mission, which continues to provide unprecedented data enabling groundbreaking discoveries about celestial objects across the universe, is a joint NASA and Italian Space Agency mission with partners and science collaborators in 12 countries. It is led by NASA’s Marshall Space Flight Center in Huntsville, Alabama. BAE Systems, Inc., headquartered in Falls Church, Virginia, manages spacecraft operations together with the University of Colorado’s Laboratory for Atmospheric and Space Physics in Boulder. Learn more about IXPE’s ongoing mission here: 

https://www.nasa.gov/ixpe

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Lee Mohon

NASA Selects Tech Proposals to Advance Search-for-Life Mission

NASA Selects Tech Proposals to Advance Search-for-Life Mission

The letters NASA on a blue circle with red and white detail, all surrounded by a black background
Credit: NASA

NASA announced Monday the selection of industry proposals to advance technologies for the agency’s Habitable Worlds Observatory concept – the first mission that would directly image Earth-like planets around stars like our Sun and study the chemical composition of their atmospheres for signs of life. This flagship space telescope also would enable wide-ranging studies of our universe and support future human exploration of Mars, our solar system, and beyond.

“The Habitable Worlds Observatory is exactly the kind of bold, forward-leaning science that only NASA can undertake,” said NASA Administrator Jared Isaacman. “Humanity is waiting for the breakthroughs this mission is capable of achieving and the questions it could help us answer about life in the universe. We intend to move with urgency, and expedite timelines to the greatest extent possible to bring these discoveries to the world.”

To achieve its science goals, the Habitable Worlds Observatory would need a stable optical system that moves no more than the width of an atom while it conducts observations. The mission also would require a coronagraph – an instrument that blocks the light of a star to better see its orbiting planets – thousands of times more capable than any space coronagraph ever built. The Habitable Worlds Observatory would be designed to allow servicing in space, to extend its lifetime and bolster its science over time.

To further the readiness of these technologies, NASA has selected proposals for three-year, fixed-price contracts from the following companies:

  • Astroscale U.S. Inc., Denver
  • BAE Systems Space and Mission Systems, Inc., Boulder, Colorado
  • Busek Co. Inc, Natick, Massachusetts
  • L3 Harris Technologies Inc., Rochester, New York
  • Lockheed Martin Inc., Palo Alto, California
  • Northrop Grumman Inc., Redondo Beach, California
  • Zecoat Co. Inc., Granite City, Illinois

“Are we alone in the universe? is an audacious question to answer, but one that our nation is poised to pursue, leveraging the groundwork we’ve laid from previous NASA flagship missions. With the Habitable Worlds Observatory, NASA will chart new frontiers for humanity’s exploration of the cosmos,” said Shawn Domagal-Goldman, director of the Astrophysics Division at NASA Headquarters in Washington. “Awards like these are a critical component of our incubator program for future missions, which combines government leadership with commercial innovation to make what is impossible today rapidly implementable in the future.”

The newly selected proposals build on previous industry involvement, which began in 2017 under NASA’s “System-Level Segmented Telescope Design” solicitations and continued with awards for large space telescope technologies in 2024. The newly selected proposals will help inform NASA’s approach to planning for the Habitable Worlds Observatory concept, as the agency builds on technologies and lessons learned from its Hubble Space Telescope, James Webb Space Telescope, and upcoming Nancy Grace Roman Space Telescope.

To learn more about NASA’s Habitable Worlds Observatory, visit:

https://nasa.gov/hwo

-end-

Alise Fisher
Headquarters, Washington
202-358-2546
alise.m.fisher@nasa.gov

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Last Updated

Jan 05, 2026

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Tiernan P. Doyle