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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The Federal Communications Commission (FCC) has approved the launch of Reflect Orbital's Earendil 1 satellite — a space mirror 18 meters wide designed to reflect sunlight to the ground.

The post Observers Beware: Reflect Orbital’s Space Mirrors Approved for Launch appeared first on Sky & Telescope.

Many observations of solar flares suffer from saturation and blooming, causing crucial information to be lost. Researchers recently validated a technique for retrieving information from saturated flare images, unlocking a treasure trove of powerful solar flares for examination.

Solutions for Saturation

Since 2010, the Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory (SDO) has been capturing nearly continuous extreme-ultraviolet images of the Sun’s disk, revealing our star’s dramatic high-energy behavior. Though SDO/AIA’s observations have transformed our understanding of the Sun’s activity, they have limitations: powerful solar flares can saturate the detector, spilling charge into nearby pixels.

This saturation and overflow compromises our ability to study the most energetic solar flares — but the “lost” information may actually be recoverable. When light from an intense flare enters SDO’s instruments, not all of it pools in the saturated region of the detector: some of the light is diffracted by the optics, and by mathematically inverting this pattern of diffracted light, researchers can attempt to extract the encoded information about the saturated region. Researchers have used this technique for more than a decade, but options for validating the results were limited until now.

Solar Orbiter Lends a Hand

Launched almost 10 years to the day after SDO, the Solar Orbiter spacecraft provides an excellent opportunity to test inversion techniques for recovering information from saturated solar images. Solar Orbiter’s Extreme Ultraviolet Imager snaps brief photos of the Sun at a rapid cadence, and its images remain unsaturated even when faced with energetic solar flares.

As described in a recent research article by Sabrina Guastavino (University of Genoa; Italian National Institute for Astrophysics) and collaborators, the ideal setup for testing the inversion technique arose on 19 March 2024, when SDO and Solar Orbiter both viewed a solar flare while separated by just 1 degree in longitude.

Guastavino’s team aligned and reprojected the data, accounting for the slightly different viewing angles of the two spacecraft, then applied an algorithm called Adaptive SE-DESAT to reconstruct the flux within the saturated portion of the SDO image. The team compared the desaturated SDO images to the unsaturated Solar Orbiter images over the course of the flare, finding the same flare morphology and similar time evolution between the two data sets.

A Treasure Trove of Desaturated Data

Overall, these results demonstrate the effectiveness of the inversion technique, though Guastavino and coauthors noted that improvements could be made during the impulsive phase of the flare, when the emission is increasing. The team identified several reasons why the results may not match during this phase, including rapid evolution of the flare during individual exposures.

Despite these areas that require further attention, the validation of this technique unlocks 16 years of solar flare observations from SDO. This especially enhances our sample of powerful solar flares, increasing the available records of the most energetic solar flares by orders of magnitude.

Citation

“Validation of an Extreme-Ultraviolet Desaturation Technique for the Atmospheric Imaging Assembly on Board the Solar Dynamics Observatory Using Observations from the Extreme Ultraviolet Imager on Board Solar Orbiter,” Sabrina Guastavino et al 2026 ApJL 1005 L50. doi:10.3847/2041-8213/ae7d2e

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NASA is once again sending scientific missions to the Moon. But under the new commercial framework for getting there, researchers need to invent a new method for how to pick where to land.

A New Process for Picking Sites

NASA’s Commercial Lunar Payload Services program is a bold innovation in organizing robotic missions to the Moon. Under this model, rather than keeping the mission process entirely in-house, the agency selects the scientific mission they want to support then simply buys a ride to the lunar surface from a commercial vendor. But, how do you pick a landing site before you know exactly how you’re getting there?

The Lunar Vulkan Imaging and Spectroscopy Explorer (Lunar-VISE) mission, set to launch in mid-2028, was one of the first programs to go through this new landing site selection process. After being officially selected in 2022, the team had just nine months to nail down exactly where their mission should touch down. A recent article led by Jean-Pierre Williams (University of California, Los Angeles) detailed exactly how the team accomplished this task and presented some lessons they learned along the way.

No Parking Lots on the Moon

Picking a landing site is no small task: for context, selecting the landing sites for each of the most recent Mars rovers took five years and multiple community workshops. The Lunar-VISE team therefore took a streamlined and logic-driven approach. They started by explicitly laying out their science objectives: Lunar-VISE’s purpose is to investigate some strangely silicate-rich volcanic formations called the Gruithuisen domes, so they had to land either on or near those. They also had to have access to boulders that were excavated from deep within the domes during a crater formation event, so they had to pick a spot with boulders relatively nearby.

In addition to objectives, they also laid out a slew of constraints. Although they needed boulders nearby, they couldn’t have too many boulders, or any particularly large boulders, since those could pose hazards for landing. There also couldn’t be any steep slopes in the field. Most of the area had to maintain a line of sight with a supporting orbiter for communications, so they couldn’t set down near any ridges. Also, they had to consider how the terrain would cast shadows as the lunar day progressed, since they didn’t want their mission cut short by freezing temperatures and a lack of solar power. As the team quipped, “many interesting, high-science value locations on the Moon may not be in proverbial ‘parking lots.'”

By combing through archival data and working with the team that operates the Lunar Reconnaissance Orbiter Camera, a key asset for making detailed maps of the Moon, the researchers found the perfect spot: alongside a 190-meter-diameter crater named Mareta. This feature is named after Mareta West, one of the first female planetary geologists at the United States Geological Survey and the scientist who selected the landing site for Apollo 11’s historic touchdown.

In addition to presenting their landing site, the researchers offered a handful of lessons to others who may someday be in the fortunate and thrilling position of needing to pick a landing spot on the Moon. For one, they urged teams to coordinate with the Lunar Reconnaissance Orbiter specialists as early as possible, since processing the imaging data for lander-quality maps is a specialized and intensive task. For another, they recommended that all of the software tools used be made publicly available so that future missions don’t need to duplicate their work.

As this article laid out, the Commercial Lunar Payload Services program and Lunar-VISE take us one step closer to making missions to the Moon routine — but we’re still figuring out exactly how to do that.

Citation

“Lunar-VISE Landing Site Selection and Characterization at Mons Gruithuisen Gamma,” Jean-Pierre Williams et al 2026 Planet. Sci. J. 7 161. doi:10.3847/PSJ/ae7d2c

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The Lucy spacecraft, en route to its primary mission targets, zipped past the main-belt asteroid Dinkinesh and revealed its tiny satellite, Selam. New research examines the surfaces and histories of these small rocky worlds.

A Stop Along the Way

In 2021, the Lucy spacecraft embarked on a 12-year mission to study several Jupiter trojan asteroids, which share Jupiter’s orbit. The spacecraft won’t have its first encounter with a Jupiter trojan until 2027, but it hasn’t been idle during its long journey. In November 2023, Lucy performed a dress rehearsal of its trojan-encounter maneuvers during a flyby of a 738-meter-wide main-belt asteroid called (152830) Dinkinesh.

During this flyby, Lucy flew within 430 km (267 mi) of the asteroid and made a surprise discovery: Dinkinesh has a tiny companion, which has been named Selam. (The name Dinkinesh comes from the Amharic name for the Lucy fossil discovered in 1974; Selam is similarly named after a hominid fossil that is sometimes called “Lucy’s baby.”) Remarkably, Selam is the first known asteroid satellite that is a contact binary, made up of two separate bodies that have gently merged into one.

Craters and Boulders

In a recent research article, Edward Bierhaus (Lockheed Martin Space) and collaborators analyzed Lucy flyby images to study the surfaces of Dinkinesh and Selam. The team analyzed global features like troughs and ridges and measured visible craters and boulders.

While the small numbers of craters detected — 29 for Dinkinesh and 3 for Selam — makes further analysis difficult, the team determined that Dinkinesh’s crater size–frequency distribution is shallower than expected, though similar to that of small near-Earth asteroids (e.g., Ryugu). The seemingly shallow distribution may be an effect of the phase angle and resolution of the observations, or it could be a sign of impact armoring or other surface processes.

The size–frequency distribution of Dinkinesh’s boulders, on the other hand, is somewhat steeper. This discovery may mean that S-type (stony) asteroids like Dinkinesh have different boulder size distributions than C-type (carbonaceous) asteroids.

Possible Histories

An analysis of the collisional timescales in the main asteroid belt suggests that Dinkinesh is a fragment of a larger asteroid that was split apart at least once, though it’s not yet possible to say which parent body it might have come from. After splitting off from its parent asteroid, Dinkinesh appears to have been subjected to the Yarkovsky–O’Keefe–Radzievskii–Paddack (YORP) effect. This effect arises when sunlight falls on a small asymmetric asteroid, creating a torque that can alter its spin rate. In extreme cases, the YORP effect can crank up an asteroid’s spin rate so much that it sheds some of its surface material or flies apart altogether.

Dinkinesh seems to show clear signs of YORP-driven structural failure. Sumak Fossa (a large trough) and Fab Dorsum (a ridge running along the asteroid’s equator) may have formed through this process. If Sumak Fossa was excavated by a YORP-induced mass-shedding event, both Fab Dorsum and Selam could have formed out of the cast-off material.

With Lucy en route to its primary objective, there’s still much for us to learn from this mission about the small bodies of our solar system. In the meantime, be sure to check out the full article linked below, as there are far more details about Dinkinesh and Selam than could be included in this short summary!

Citation

“The Geology of a Small Main-Belt S-Class Binary Asteroid System: Dinkinesh and Its Contact Binary Satellite Selam as Observed by the Lucy Mission,” E. B. Bierhaus et al 2025 Planet. Sci. J. 6 299. doi:10.3847/PSJ/ae1968

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In September 2022, the Double Asteroid Redirection Test (DART) mission served as the first attempt at redirecting a near-Earth asteroid — an experiment testing humanity’s ability to fend off any threatening Earth-bound asteroids. A recent study presents the first 3D reconstruction of the impact ejecta, suggesting that the blown-out material is more complex than previous models considered.

DART-ing into Dimorphos 

The DART spacecraft intentionally smashed into Dimorphos, the small and unassuming moon of the larger asteroid Didymos. This space-based crash test aimed to determine if kinetic impactors like DART could successfully change an asteroid’s course through the solar system. Dimorphos’s orbit was indeed shortened by roughly 30 minutes, confirming that ramming an asteroid with a spacecraft could be a viable method of planetary defense. However, determining exactly how much an asteroid’s path will be altered is not necessarily straightforward. When a spacecraft collides with an asteroid, the impactor imparts momentum to the target, and any material excavated from the impact site can also alter the asteroid’s course.

DART’s impact launched a significant spray of rubble, or what researchers call an ejecta curtain. The ejecta curtain is typically modeled as a cone, using a simple geometry to determine its contribution to momentum transfer. However, when looking closely at imaging taken soon after the collision, the real physical structure of the ejecta appears to be more complex. Untangling the true 3D distribution of the ejecta is necessary to understand how momentum was actually distributed among escaping ejecta, better estimate the total mass ejected from Dimorphos, and improve modeling of the Didymos system’s orbit after impact.

Determining Debris Distribution

Seeking to better characterize the ejecta curtain, a team led by J. D. P. Deshapriya from Italy’s National Institute for Astrophysics used data from the Light Italian CubeSat for Imaging of Asteroids (LICIACube) that flew behind the DART spacecraft to capture images of the system shortly after the impact. After careful image handling to bring out diffuse and faint material, the researchers identified 14 distinct ejecta features across the flyby imaging. LICIACube viewed the aftermath both side on and face on, providing valuable 3D information about the distribution and motion of the ejecta. 

Using 3D modeling software, the researchers traced each of the 14 distinct features across the images and reconstructed a 3D representation of the ejecta morphology. While earlier models assumed symmetric cone-like geometries, this 3D modeling revealed clear asymmetric and non-uniform structures within the ejecta curtain. These variations point to underlying heterogeneities in the impact site on Dimorphos — surface and subsurface composition naturally link to the resulting ejecta distribution according to previous laboratory experiments. The spatial and directional features uncovered in this study highlight the limitations of models that attempt to characterize ejecta curtains with symmetric and uniform distributions. Refining these model parameters will better match observations and better predict momentum transfer in future missions. 

Planetary Defense

What does this mean for planetary defense? While simplified symmetric cone models provide helpful approximations for kinetic impactor missions, they do not fully capture the true complexity of the impact. This study shows that local variations in an asteroid’s surface and interior properties can directly influence the resulting ejecta distribution and motion. The true momentum imparted to the target asteroid depends heavily on the specific ejecta material, and these details inform how effective planetary defense missions can be in redirecting asteroids. Incorporating realistic, observation-driven ejecta distributions into modeling frameworks is essential to achieve reliable predictions for future planetary defense missions.

Citation

“3D Reconstruction of DART Ejecta at Dimorphos Reveals an Anisotropic, Filamentary Structure,” J. D. P Deshapriya et al 2026 Planet. Sci. J. 7 4. doi:10.3847/PSJ/ae2c64

The post Pulling Back the Curtain on DART Ejecta appeared first on AAS Nova.

Earthlike yet alien, Titan is the only solar system body other than Earth known to host persistent liquid on its surface. The glint of sunlight on this surface liquid provides a means to study the complex interplay between Titan’s seas, shorelines, and atmosphere.

When the Sun Hits the Sea as Seen by Cassini, That’s a Mare

In 2009, the Saturn-orbiting Cassini spacecraft spotted the glare of sunlight reflecting off a sea of liquid on the surface of Titan, Saturn’s largest moon. This observation of specular (i.e., “mirror-like”) reflection, or sunglint, confirmed the presence of liquid on Titan’s surface — what researchers now know to be oily lakes and seas of liquid hydrocarbons like methane and ethane.

A recent research article from Michael Heslar and Jason Barnes (University of Idaho) yields new insight into the behavior of Titan’s seas and coastal regions in Punga Mare. Punga Mare, located nearly at the north pole, is the smallest of Titan’s named seas and holds the distinction of being the first place where extraterrestrial waves were definitively identified.

Summering at Punga Mare

In the Cassini observation selected for this study, it’s summertime in the northern hemisphere, with balmy temperatures hovering just above 90K (−298℉/−183℃). Cassini viewed Punga Mare from an altitude of roughly 6,000 kilometers and at an oblique angle of 126 degrees. From this angle, Titan’s landmasses appear dark and the sea appears bright.

Several anomalously bright features, collectively called specular features, appear in and near Punga Mare. These features are examples of sunglint and sun glitter. Sunglint occurs when sunlight reflects off a smooth surface as light reflects off a mirror, with the angle of the incoming sunlight equal to the observer’s viewing angle. Sun glitter is a related phenomenon that occurs outside the sunglint zone, where localized changes in the angle of the surface — from waves, for example — reflect sunlight toward the observer.

Coasts, Islands, and Inlets

Heslar and Barnes identified specular features along the coastline, bordering a chain of islands, out at sea, and in coastal inlets.

The bright areas along the coast appear to overlap both the sea surface and the land surface. While it’s not yet clear exactly what causes this brilliant coastal outline, Heslar and Barnes speculated that it may be evidence for waves along the coastline; rough seas may also be the cause of the sun glitter illuminating the Hawaiki island chain and out at sea.

The specular features associated with inlets may mark where rivers flow into or out of Punga Mare. Rather than wave activity, these bright areas might mark where nitrogen has bubbled up to the surface.

Altogether, this study demonstrated the variety and depth of information that can be gleaned from a single sunglint observation — and the authors closed by noting how effective an orbiter would be for studying ocean behavior on Titan. NASA’s upcoming Dragonfly mission may also be able to capture sunglint as the spacecraft leapfrogs across Titan’s surface.

Citation

“Sea Surface and Hydrological Activity Observed in Titan’s Punga Mare,” Michael F. Heslar and Jason W. Barnes 2025 Planet. Sci. J. 6 74. doi:10.3847/PSJ/adbc9e

The post Sun Glitter and Sunglint on Titan’s Hydrocarbon Seas appeared first on AAS Nova.