A collaboration of researchers in North America has reported their findings from the first diagnostic X-ray imaging performed in space. X-ray images recorded during an orbital spaceflight exhibited similar overall quality to those taken preflight on Earth, demonstrating the feasibility of adding radiography as a diagnostic tool for crew health.

With humans venturing further into space and spending more time in this harsh environment, the risk of adverse medical events increases. Accurate and timely diagnosis and treatment is a must-have. Currently, the only reliable medical imaging modality available to astronauts in spaceflight is ultrasonography – which is operator dependent, requires substantial training and relies on limited acoustic windows.

X-ray imaging, on the other hand, benefits from low operator dependence, rapid acquisition and typically higher spatial resolution than ultrasound. Digital radiography could also offer superior diagnostic capabilities for many medical conditions of concern during spaceflight, including dental disease, musculoskeletal trauma, inhalational injury, collapsed lung and arthritis.

Traditional X-ray scanning systems are bulky, produce a lot of radiation and are sensitive to motion – making them less than ideal for sending into space. But a new generation of portable X-ray scanners shows potential to survive the spaceflight and be operated by crew members with minimal training.

“It’s been a dream for aerospace medicine to have more than one imaging modality for diagnosing illnesses and injuries in space,” says lead researcher Sheyna Gifford, an assistant professor of aerospace medicine at the Mayo Clinic in Rochester, MN, in a press statement.

Scanning in space

In a study led by co-author David Lerner, the researchers first demonstrated the feasibility of X-ray imaging in simulated microgravity in 2022. During a parabolic flight, they used a commercial off-the-shelf digital radiography system to successfully capture radiographs of a human subject and a phantom during lunar gravity (1/6g), Martian gravity (1/3g) and microgravity.

In this latest project, reported in in Radiology, Gifford and her team investigated the performance of a similar portable digital radiography system aboard the Dragon spacecraft, during the Fram2 spaceflight mission, a 3.5-day polar orbital flight launched on 31 March 2025 on a SpaceX Falcon 9 rocket. The imaging system comprised a commercial off-the-shelf, FDA-cleared, portable, digital X-ray generator (Impact Wireless; MinXray) along with an FDA-cleared flat-panel detector.

Prior to the mission, three crew members received 4 hr of training on the portable X-ray system and acquired preflight X-ray images of the hand, forearm, abdomen, pelvis, chest and a quality control phantom. They then recorded the same anatomic and phantom images whilst in space, and also imaged a smartwatch to investigate the potential for non-destructive testing.

During anatomic imaging, the devices were handheld by the crew members, while the phantom and smartwatch were secured to the detector for imaging. The crew reported that they found it easy to use the X-ray system and follow the imaging protocols.

Back on Earth

To assess the quality of the seven X-ray images acquired by the crew, three independent radiologists evaluated and compared the preflight and in-flight anatomic radiographs, finding no differences in overall image quality, contrast resolution or spatial resolution. For central-body radiographs (chest, abdomen and pelvis), image positioning was worse in-flight than preflight. Despite this, all X-rays achieved good or near-excellent diagnostic quality (rated on a  5-point Likert scale).

Phantom radiographs recorded in space exhibited good spatial and contrast resolution, imaging low-contrast targets down to the smallest 2-mm target and easily visualizing high-contrast meshes ranging from 20 to 60 lines per inch, with 80 lines per inch remaining visible. The smartwatch radiograph clearly showed the watch’s internal components at the submillimetre scale.

The research team found that the X-ray generator had sustained minor re-entry damage, but its internal components and X-ray output were not affected. Similarly, the detector passed visual inspection and quality control tests. The researchers also recorded a set of postflight X-rays (on non-crewmembers) following the same in-flight protocols. These showed no qualitative differences from the preflight or in-flight radiographs.

“By acquiring the first human and equipment X-rays in space, our study demonstrates the feasibility of in-orbit radiography and expanded diagnostic capabilities for crew health and hardware evaluation,” says Gifford. “Acquiring diagnostically useful X-rays in space is something that anyone can do. Three very talented nonmedical people with four hours of training in one of the harshest environments did it right and did it well.”

Gifford points out that a spaceflight-ready radiography system could also prove indispensable for mission-critical non-medical tasks. “For sustained human presence in space, X-rays are critical not just for crew members but also for other mission components like electronics and spacesuits. The only way to look inside these objects without taking them apart is to X-ray them,” she explains.

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A compact optical technology that has already proved its worth in Earth-bound applications could be on its way to space after researchers at the University of California San Diego, US showed that it can map the Sun’s magnetic field just as well as traditional instruments. By making polarization gratings from specially engineered metasurfaces rather than a complex assembly of optics, the researchers say that future solar-observing missions could benefit from reduced complexity and cost as well as size.

“Our work makes use of recent advancements in nanoscale optical technologies to help improve the hardware for making astronomical observations of the Sun,” says study leader Noah Rubin of UC San Diego’s Jacobs School of Engineering. “We believe this is one of the first times that metasurface optics – which have been a subject of intense interest in both academic research and industry for about a decade – have been used to improve scientific instrumentation of any kind outside of a lab/academic proof-of-concept.”

Polarized light and solar magnetic fields

Although light emitted by the Sun is generally unpolarized – that is, the light waves do not vibrate along a particular axis – strong magnetic fields that develop near sunspots can polarize this light via the quantum mechanical Zeeman effect. These magnetic fields are closely associated with space weather events such as solar storms that can damage electronic infrastructure both on Earth and in orbit. Studying the Sun’s magnetic activity by monitoring areas of polarized light is thus an important step towards detecting or predicting such storms in time to take protective action.

Usually, measuring the polarization state of light means analysing different polarization directions using a device such as a waveplate that mechanically rotates between exposures. Rubin compares this process to taking several photographs through polarized sunglasses held at different angles, then combining them to obtain a fuller picture of what’s going on.

While this technique works, and instruments that use it have already been sent into space, the image analysis process is very time-consuming. It also requires an external power source, and the need to mechanically rotate the waveplate introduces extra complexity and cost, says Rubin.

“In space-based applications, a satellite itself can be moving while this component reorients, causing a highly undesirable blurring effect,” he explains. “As a result, designers of these systems often invest considerable resources into mechanical remediation and engineering to correct the motion of the telescope on the satellite, and this frequently ends up being substantially more expensive than the telescope optics themselves.”

A metasurface solution

In the new study, which is detailed in Science Advances, Rubin and colleagues solved this problem by creating a polarization-sensitive metasurface that splits light into its different polarization components. A camera-like system containing this metasurface polarization grating can then form multiple images of a scene in parallel. Rubin explains that each image in this scene is analysed with respect to a different polarization state, meaning that the system can measure the polarization of light simultaneously and passively in a single camera frame.

Rubin notes that this technique of condensing an instrument that would ordinarily involve a complex assembly of optics into a single, flat surface has previously made its way into applications as diverse as facial recognition in mobile phones and the preparation of complex photon states in quantum optics experiments. “In this work, we show that these advantages translate to polarization imaging in astronomy,” he tells Physics World.

Comparable results

Working with industrial partners at BAE Systems Space & Mission Systems in Colorado, US (formerly known as Ball Aerospace, which Rubin describes as “well-known for its involvement in the development of the James Webb Space Telescope, Hubble and countless other NASA missions”), the team designed a specialized telescope built around such a metasurface polarization grating. They also deployed their instrument on the Dunn Solar Telescope in New Mexico, US, and showed that they could quantitatively map the magnetic fields in sunspots by capturing simultaneous polarization images of these spots.

The researchers report that their results were comparable to those obtained by the state-of-the-art NASA Solar Dynamics Observatory mission in-orbit, highlighting what Rubin calls “the significant advantages that these metasurface components can offer when designed in conjunction with more traditional optical systems”. The UC San Diego team is now exploring ways of integrating its technology into future NASA solar-observing space missions.

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A galaxy that formed around a billion years after the Big Bang is in its death throes thanks to a powerful galactic wind that is blasting its gas into space, say astronomers at Australia’s Swinburne University of Technology. The discovery, which is based on data from the James Webb Space Telescope (JWST) and the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, could help explain why some of the universe’s earliest massive galaxies ceased to form new stars.

One of the JWST’s most surprising discoveries is that when the universe was between one and two billion years old, it already contained large numbers of massive galaxies. Astronomers think these galaxies may have acquired most of their mass in intense bursts of star formation. But at some point, that process stopped: in technical terms, the galaxies became quiescent.

“These galaxies seemed to have formed all their stars very quickly and then they suddenly died, all within the first two billion years of the universe being formed,” says Rebecca Davies, who led the new research.

The CRISTAL-02 galaxy

One possible explanation for the onset of quiescence is that when galaxies collide with each other, the resulting winds “blow away” the hydrogen fuel required for new stars to form. To investigate this hypothesis, Davies and colleagues focused on a galaxy called CRISTAL-02, which was one of 20 galaxies in the recent ALMA-CRISTAL survey of early star-forming galaxies.

“When we looked at the data, it stood out because it was the only one that showed strong evidence for a galaxy wind,” Davies explains. “We saw this as an excellent opportunity to study how winds impacted the evolution of galaxies in the early universe.”

The light from CRISTAL-02 travelled for approximately 12.7 billion years to reach us, meaning that we see it as it was one billion years after the Big Bang. Because the universe has been expanding since then, the galaxy’s spectra appear highly red-shifted. This meant the Swinburne astronomers needed the JWST’s infrared-sensing capabilities to analyse a spectral feature known as the hydrogen-alpha (Hα) line that is normally red. They also used ALMA to analyse CRISTAL-02’s C II line, which comes from ionized carbon and has a (non-redshifted) wavelength of 158 mm. Both emission lines can yield important information about the properties of early galaxies.

Living fast and dying young

From the ALMA-CRISTAL survey’s measurements of Hα luminosity, astronomers knew that CRISTAL-02 forms stars at a rate of around 260 M_☉ per year. This is about three times the average value for “main-sequence” star-forming galaxies at similar mass and redshifts.

The latest observations, however, suggest that it won’t maintain this pace for long. Davies and colleagues identified a huge plume of C II emissions that extends as far as 7 kiloparsecs (kpc) to the north-east of CRISTAL-02, making it almost as long as the galaxy itself. This is a telltale sign that gas is being driven out of the galaxy. The fact that the gas in this plume is blue-shifted by 100 km s^-1 lends further support to this explanation.

If this rapid blowout continues, Davies says that CRISTAL-02 will cease to exist in less than 50 million years. But the team’s findings may have implications beyond the fate of this single galaxy. “Our results could help to explain how some of the earliest massive quiescent galaxies in the universe behave,” she tells Physics World. “When the JWST started observing distant galaxies in 2022, it found far more evolved galaxies in the early universe than models predicted. These galaxies seemed to have formed all their stars very quickly and then suddenly died, all within the first two billion years of the universe. The galaxy we discovered seems to be following this path.”

Learning about the early universe

Davies explains that because the early universe was much more compact than it is now, collisions between galaxies were common. During such collisions, gas funnels towards the galactic centres, triggering strong bursts of star formation but also producing strong winds that eventually drive the gas away. “If many early galaxies collide and experience rapid growth, then it may not be surprising at all that we see so many dead galaxies in the early universe,” she says.

The researchers stress that the present work, which is detailed in the Monthly Notices of the Royal Astronomical Society, is based on a case study of just one galaxy. They now need to observe other early, massive galaxies caught during periods of intense growth to determine whether they, too, experience powerful winds that could rapidly expel their gas and stop them from forming stars.

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Black carbon particles released by rocket launches remain in the upper atmosphere for much longer than sooty particles produced by sources on the ground. This finding, which comes from a study led by researchers at University College London (UCL), UK, suggests that the soot created in deploying “megaconstellations” containing hundreds or thousands of satellites could have poorly understood and potentially serious consequences for the Earth’s climate.

“Rocket launches are a unique source of pollution, injecting harmful chemicals directly into the upper layers of the atmosphere and contaminating Earth’s last remaining relatively pristine environment,” says the study’s lead author, UCL atmospheric chemist Connor Barker.

The number of rockets being launched into space has increased dramatically since 2019, and the trend shows few signs of stopping. This year has already seen more launches than the whole of 2020, and space industry experts believe the eventual total could surpass 2025’s figure of 329. The increase has primarily been driven by the Falcon 9 rockets launched by the US firm SpaceX, though China also logged a record 92 launch attempts in 2025.

“An unregulated geoengineering experiment”

In the new work, Barker and colleagues analysed data from rocket launches and satellite re-entries from 2020 to 2022. Their results, which they detail in Earth’s Future, show that the soot particles lingering in the upper atmosphere are 540 times more effective at altering climate than ground-based soot emissions from sources such as cars and power plants.

“Space industry pollution is like an unregulated geoengineering experiment,” says Barker. Soot particles from burning kerosene in rocket fuel absorb sunlight, he explains, which prevents it from reaching the Earth’s surface. The result is a small cooling effect, which might sound like a good thing in the context of rising global temperatures. However, Barker stresses that this cooling is minimal compared to the global warming caused by other human-generated emissions, while the particles themselves could have “many other serious unintended consequences”.

Predictions likely to underestimate future impact

As well as quantifying recent space industry emissions, the researchers make predictions about future ones. According to their calculations, by 2029 the space industry will be releasing about 870 tonnes of soot into the atmosphere each year. By way of comparison, Baker notes that according to the latest UK government figures, the annual emissions of the country’s entire passenger car fleet amounted to just 728 tonnes.

The team based its predictions on projections of data from 2020-2022, which is considered the beginning of the megaconstellation satellite era. Because of this, Barker cautions that they are likely to be underestimates, making the problem even more urgent. “It is critical that we understand the environmental impacts of satellite megaconstellations now while their impact is small, before any unforeseen consequences are difficult to reverse or repair,” he tells Physics World.

While scientists have made great progress in the last few years, Baker says that are still large uncertainties in our emission estimates for the industry and our understanding of how they affect the atmosphere. “We hope that this work spurs further research to measure space industry emissions and highlights the need to regulate the geoengineering impacts of the space industry,” he says.

Team leader Eloise Marais, a professor of atmospheric chemistry and air quality at UCL, echoes this sentiment. “So far, there has been limited effort to effectively regulate this type of pollution,” she says.

The researchers are now working on an emissions tracker to visualize these emissions across the entire space age. “We are also using satellite imagery to remotely detect and quantify rocket launch emissions,” Barker reveals.

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Thanks to new “transit” observations of the hot Jupiter exoplanet WASP-94A b using the James Webb Space Telescope (JWST), researchers at Johns Hopkins University in the US have discovered a striking weather pattern on this distant world. Their work could help provide a clearer picture of the atmospheres on exoplanets, which has been very limited until now.

When an exoplanet passes in front of (or transits) its host star, some of the light from that star passes through the planet’s atmosphere. By detecting this light using telescopes, either ground-based or in space, astronomers are able to obtain the exoplanet’s atmospheric light spectrum.

A team led by Sagnick Mukherjee and David Sing has now analysed data on WASP-94A b from the space-based JWST and have found that the mornings on this exoplanet are extremely cloudy – with water absorption features in the spectrum – while its evenings are very clear. Clouds likely form on the planet’s colder, permanent nightside where temperatures are low enough for minerals to condense. Winds then carry those clouds towards the morning limb (the leading edge of the atmosphere), explains Mukherjee.

“As these cloud particles are dragged farther toward the hotter dayside, the clouds evaporate or sink deeper, leaving the evening side much clearer,” he says. “This is a clear discovery of a planet-wide cloud cycle in action on a distant exoplanet.”

Part of a broader survey

The researchers, who detail their findings in Science, decided to study WASP-94A b as part of a broader survey of exoplanet atmospheres with the JWST called the “Grand Tour Program”. The goal of this project, says Mukherjee, is to better understand the composition of these exoplanets and the physical processes at play in their atmospheres.

One of the main difficulties encountered during such observations is how small the signals that we are trying to look at are, he explains. However, in this case, the asymmetry between the morning and evening side of the planet was rather dramatic, which made it possible to separately probe the two.

Until now, researchers only had access to a single averaged spectrum of WASP-94A b – and indeed most other exoplanets studied over the last decade –from observations made by the Hubble telescope, for example. The chemical composition of the exoplanet’s atmosphere was therefore highly biased, says Mukherjee, and it was thought that the levels of oxygen and carbon there were hundreds of times higher than on the Sun. “This finding baffled us because this result could not be explained by planet formation theories. The new data show that WASP-94A b only contains only about five times as much oxygen and carbon.”

“Being able to resolve the cloudy morning and clear evening separately therefore gives us a much cleaner view of what the atmosphere is actually made of,” Mukherjee tells Physics World. “And this is not just relevant to hot-Jupiters like WASP-94A b, but might be extended to all exoplanet atmospheres that we are trying to understand using the transit method.”

“One of the most exciting aspects”

For Mukherjee, this is one of the most exciting aspects of the JWST era. “We are taking a step beyond simply detecting the atmospheres of distant planets and are now beginning to map their weather, chemistry, and three-dimensional structure in extraordinary detail.”

Indeed, using WASP-94A b as a benchmark, the Johns Hopkins team has already studied eight other hot gas giants and discovered the same distinctive cloud cycle on two other worlds: WASP-39 b and WASP-17 b. “Inspired by these observations, our collaboration, co-led by David Sing, myself and our colleague Guangwei Fu, is about to receive more than 180 hours of new JWST data to understand weather on diverse exoplanets and measure how their weather and cloud-coverage vary with planet temperature and gravity,” reveals Mukherjee.

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