It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Tuesday, September 15, 2026
SPACE/COSMOS
Venus ate its moon
Study explains why Earth’s ‘twin’ lacks rocky satellite
Scientists have long speculated why Venus, with a similar size, mass, and structure to Earth, doesn’t have a moon. New UC Riverside research shows it’s because our hungry twin likely swallowed it.
In the past, scientists have theorized that Venus possibly had a moon at one time that got hit with something massive, obliterating it. Other theories centered around the idea that Venus never underwent a collision that formed a moon in the first place.
The new research, published in The Astrophysical Journal, shows that neither theory fits. “My study shows Venus didn’t require a catastrophe to arrive at what we can see today,” said UCR astrophysicist and lead author Stephen Kane. “It turns out the gravity of the planet itself combined with the rate at which it spins naturally caused the moon to collapse on top of it.”
Scientists can precisely measure the distance between Earth and the moon because NASA’s Apollo 11 landing left mirrors there. “We know that the moon is slowly moving away from the planet, at a rate of around four centimeters per year,” Kane said. This distancing, Kane said, is happening because Earth spins at a relatively fast 24 hours per rotation. The energy from this spinning gets transferred to the moon, causing it to distance itself.
Venus has the exact opposite situation. It takes that planet 243 Earth days to complete a single rotation. So, rather than gradually moving away, the slow spin and the planet’s gravity would cause a moon to spiral inward toward a collision.
To test this idea, Kane wrote computer models based on the physics of how planetary bodies interact through gravity. He first reproduced the evolution of Earth and its moon to make sure the model accurately represented a known system.
Then he varied Venus’ rotation rate and the size of its hypothetical moons, testing moons with masses ranging from half to ten times the mass of Earth’s moon. In most simulations, the result was the same: the moon crashed into Venus. And the more massive the moon, the faster it crashed.
“When I made this discovery, I was shocked,” Kane said. “I thought surely the broad range of scenarios I was exploring would lead to a variety of results. But it all went pretty much in the same direction.”
The finding does not prove that Venus once had a moon. Kane believes it may have, but whether one ever formed remains an open question. The study does show that if Venus had a moon, it could not have continued existing indefinitely.
Finding physical evidence of such a collision would be difficult. Roughly 80% of Venus’ surface is similar in age, evidence of a major resurfacing event about a billion years ago that erased much of the planet’s earlier geological history.
Evidence could instead lie beneath the surface. Scientists believe Earth’s moon formed after a massive collision early in the planet’s history, and seismic studies have revealed unusual structures deep inside Earth that may be remnants of that event. Similar measurements on Venus could offer clues about whether it once absorbed a moon.
Such a collision could also help scientists understand another longstanding mystery about Venus: whether Earth’s nearest planetary neighbor was ever capable of hosting life.
A moon crashing into Venus would have transferred enormous energy and angular momentum to the planet, potentially changing its rotation, geology, and climate. If Venus once had oceans or other conditions favorable to life, such an impact could have altered the course of the planet’s evolution.
The implications extend beyond Venus. Scientists searching for potentially habitable worlds around other stars often look for planets resembling Earth and consider the presence of a moon one factor that could influence habitability.
Earth’s moon drives tides, may have helped keep the planet geologically active, and has profoundly influenced Earth’s evolution. Scientists do not know, however, whether a large moon is necessary for life.
“My feeling is there are benefits to having a moon, but it isn’t required for habitability,” Kane said. “The moon has definitely changed the way Earth has evolved through time, but we don’t fully know how important that role is.”
Kane’s findings suggest that even planets capable of forming moons may not be able to keep them. Slowly rotating worlds could send their moons spiraling toward their surfaces, dramatically changing the planets in the process.
“When people think about Earth twins around other stars, one question they ask is, ‘Does it have a moon?’” Kane said. “My study shows a disturbing scenario for many of those cases. If these planets don’t rotate fast enough, the moon will crash to the surface, and that would change the course of history for those planets.”
Cambridge, MA (September 14, 2026) —A new study of nine nearby galaxies has shown that actively growing supermassive black holes may contribute to star formation, instead preventing star formation, in their host galaxies.
The research, based on observations from the VLT/MUSE instrument, shows that active galactic nuclei (AGN), or bright regions powered by material falling into a supermassive black hole, are associated with star-forming rings or arcs, cone-shaped regions of energized gas, and fast “shocks,” which occur when energy outflows interact with surrounding gas.
The findings give a new perspective on how AGN feedback could influence the growth and evolution of galaxies.
“Once we resolved them, we could see that they not only accrete things, but they also eject things,” said Peixin Zhu, graduate student and astronomer at the Center for Astrophysics. “The injection and accretion are linked with each other.”
The study focused on galaxies whose central black holes are actively accreting, or pulling in, nearby material.
“We’re seeing that black holes are not just consuming material at the centers of galaxies, but they’re actively reshaping their surroundings,” said Lisa Kewley, an astrophysicist at the Center for Astrophysics | Harvard & Smithsonian, director of the Center, and Zhu’s advisor. “This work helps us understand a complex feedback cycle that plays an important role in galaxy evolution.”
The team used a new three-dimensional diagnostic technique to distinguish among three sources: star formation, radiation from the active black hole and excitation by shocks. Shock excitation occurs when high-speed outflows from the central black hole collide with the interstellar medium.
The galaxy NGC1386, shown in grayscale on the left and zoomed in to the central region on the right. The colors represent star formation in red, black-hole radiation in blue, and shocks in yellow. Image courtesy Peixin Zhu.
Across the sample, the researchers found that star-forming rings or arcs appeared at distances of about 0.8 to 6 kiloparsecs from the galactic center. Ionized cones of black-hole radiation extended outward from the galaxies’ discs, while central regions dominated by fast shocks often extended perpendicular to those bicones.
The researchers also found evidence for shocks in directions perpendicular to the AGN bicones. Zhu notes that these shocks are broadly consistent with interactions between AGN jets and the interstellar medium, although winds from the active black hole may also contribute, particularly in galaxies with lower-power jets.
“The most interesting phenomena about shocks is that they always go perpendicular to where the black hole’s injected outflows go,” Peixin said. “It is very common, and we see it consistently appearing across the whole nine galaxies.”
The study’s results combined high-resolution observations and detailed theoretical models. The MUSE instrument provided spatially-resolved optical data, while the state-of-the-art theoretical models built by Zhu and her colleagues, astrophysicists Lisa Kewley of the Center for Astrophysics and Ralph Sutherland of the Australian National University, allowed them to compare observations with predictions for black hole activity, star formation and shocks. Chandra X-ray observations also independently supported the researchers’ interpretation.
The results demonstrate that actively growing black holes have a complex cycle of accretion, outflow and interaction with their surrounding galaxies. By separating the effects of black hole radiation, star formation and shocks, the study provides a clearer view of that cycle and its relationship to star formation.
About the Center for Astrophysics | Harvard & Smithsonian
The Center for Astrophysics | Harvard & Smithsonian is a collaboration between the Smithsonian Astrophysical Observatory and the Harvard College Observatory designed to ask, and ultimately answer, humanity’s greatest unresolved questions about the universe.
The galaxy NGC1386, shown in grayscale on the left and zoomed in to the central region on the right. The colors represent star formation in red, black-hole radiation in blue, and shocks in yellow. Image courtesy Peixin Zhu.
With growing concerns over the impact threat of near-Earth small bodies and the utilization of space resources, the orbital evolution of binary asteroid systems has become an important subject in space science. When describing the full two-body dynamics of such systems, the gravitational potential of irregular bodies is determined by both their positions and attitudes, leading to coupling between translational and rotational motions, and the resulting model complexity significantly exceeds that of the classical two-body problem. Although existing numerical methods, such as explicit Runge–Kutta integrators, are widely used, they fail to preserve the symplectic structure and Lie group geometric properties of the system. In long-term simulations, key conserved quantities such as total energy and angular momentum are prone to numerical drift, severely undermining the long-term credibility of orbital predictions. While Lie group variational integrators can preserve geometric structure to a certain extent, their implicit equations are formulated on Lie group elements, which incurs substantial computational overhead. Therefore, how to construct a high-performance integration method that simultaneously achieves numerical accuracy, structure preservation, and computational efficiency has become a core challenge in the long-term evolutionary simulation of binary asteroid systems.
In a recent study published in Space: Science & Technology, the team led by Guo Yongxin from the College of Physics, Liaoning University, proposed a numerical method for the full two-body dynamics of a double-dumbbell system based on the Hamel variational integrator. The study employs the special Euclidean group SE(3) to uniformly describe the translational and rotational motions of the dumbbell-shaped rigid bodies, introduces a body-fixed coordinate frame attached to the second dumbbell, reduces the system motion to the evolution of relative position and attitude, and constructs discrete equations of motion on the Lie algebra based on the discrete Hamilton's principle, thereby achieving an efficient iterative scheme for the Hamel variational integrator. Simulation results demonstrate that in regular-shaped examples, the proposed method outperforms Lie group variational integrators in energy conservation and orthogonality preservation, and, since the implicit equations are formulated on the Lie algebra rather than on Lie group elements, it incurs lower computational cost. In irregular-shaped examples, the total energy error and rotation matrix orthogonality error of the proposed method are significantly superior to those of the Runge–Kutta method, which fails to maintain orthogonality structure and consequently leads to substantial accumulation of force and torque computation errors over time. Irregular shape also induces noticeable deviations in the barycentric trajectory of the double-dumbbell system along specific directions, indicating that the irregular geometry of celestial bodies has a non-negligible effect on full two-body motion. This study provides a numerical scheme that balances structure preservation and computational efficiency for high-precision long-term orbital evolution of binary asteroid systems, offering significant methodological support for planetary defense mission planning and long-term dynamical prediction of binary systems.
First, this paper focuses on the full two-body dynamics problem in the orbital evolution of binary asteroid systems. Binary asteroids constitute a significant proportion of near-Earth asteroids, with approximately 16% of near-Earth asteroids possibly being binary systems; the assessment of their impact threat and the planning of exploration missions both rely on high-precision predictions of the long-term dynamical behavior of such systems. In the full two-body problem, the gravitational potential of irregular bodies is determined by both their positions and attitudes, resulting in coupling between translational and rotational motions, and the model complexity is substantially greater than that of the classical two-body problem. Owing to the relatively small separation between the two asteroids in a binary system and the modest difference in their masses, each binary system can be modeled as a rigid dumbbell, thereby establishing a double-dumbbell full two-body system as shown in Fig. 1. The system consists of two dumbbell-shaped rigid bodies, each composed of two asteroids connected by a massless rod. To describe the configuration of the dumbbells, the study employs the special Euclidean group SE(3) to uniformly represent position and attitude, and introduces a body-fixed coordinate frame attached to the second dumbbell, reducing the system motion to the evolution of the relative position and attitude of the first dumbbell with respect to the second. This modeling approach avoids the singularity issues inherent in Euler angle representations and naturally captures the coupling effects between translation and rotation.
Second, based on the discrete Hamilton's principle, the paper constructs a Hamel variational integrator tailored for the double-dumbbell system. The core idea of the Hamel variational integrator is to utilize the body-frame motion framework provided by the left-invariant vector fields on the Lie group, expressing both the continuous and discrete equations of motion entirely on the Lie algebra. Fig. 2 illustrates the computational procedure for the double-dumbbell system: first, the continuous Euler–Lagrange equations and Hamilton equations are derived from Hamilton's principle; subsequently, the discrete Hamilton's principle is employed to construct the discrete Lagrangian, yielding the discrete equations of motion on the Lie algebra. Since all equations are formulated at the Lie algebra level, the computational complexity of the implicit equations is lower than that of Lie group variational integrators based on Lie group elements. Through the discrete Legendre transform, an explicit iterative scheme in the Hamiltonian form is established; within each time step, the state update is accomplished by solving the implicit equations on the Lie algebra, sequentially obtaining the evolution of the relative position, relative attitude, and each momentum variable. This method preserves both the symplectic and Lie group structures of the system, while maintaining long-term exact conservation of total energy and angular momentum.
Finally, this paper systematically validates the performance of the Hamel variational integrator through numerical simulations of both regular-shaped and irregular-shaped dumbbell models. Fig. 3 presents the energy evolution over time, in which the kinetic and potential energies exhibit periodic interconversion; at the ninth unit of time, the two dumbbells reach their closest distance, corresponding to minimum potential energy and maximum kinetic energy, while the total energy remains constant. Figs. 4 and 5 compare the three methods in terms of energy error and orthogonality error, respectively: both the Hamel variational integrator and the Lie group variational integrator outperform the Runge–Kutta method, with the Hamel variational integrator demonstrating superior structure-preserving performance. The CPU time comparison in Fig. 6 reveals that the Hamel variational integrator achieves slightly higher computational efficiency than the Lie group variational integrator, as its implicit equations are formulated on the Lie algebra rather than on Lie group elements. In the irregular-shaped examples, the Runge–Kutta method fails to preserve the orthogonality of the rotation matrix, leading to significant accumulation of force and torque computation errors over time, whereas the Hamel variational integrator consistently maintains low errors. By comparing the barycentric trajectories of the two dumbbell models, it is found that the irregular shape induces a noticeable deviation in the y-direction of the barycentric trajectory, indicating that the irregular geometry of celestial bodies exerts a non-negligible influence on full two-body motion. This study provides a numerical method that balances structure preservation and computational efficiency for long-term high-precision orbital evolution of binary asteroid systems.
With the intensifying space confrontation in geostationary orbit (GEO), the U.S. GSSAP (Geosynchronous Space Situational Awareness Program) satellites have conducted hundreds of close-range observation operations on dozens of on-orbit satellites in the vicinity of GEO. The acquisition of multi-aspect information from non-cooperative targets has thus become a critical component of space security assessment. Close-range spacecraft operations, which employ relative motion configurations such as fly-around, hovering, and drifting flight, provide an effective technical means for approaching and observing targets to obtain multi-aspect payload information. However, existing studies predominantly focus on the control design of a single relative motion configuration, which fails to satisfy the complex mission requirements of multi-aspect observation. The combination of multiple models for observation presents multiple challenges, including smooth switching between modes, fuel optimization, strategy design algorithms, and analysis of payload parameter effects. Therefore, how to coordinately plan a sequential combination of multiple close-range operation models under minimum fuel constraints to efficiently acquire multi-aspect information of non-cooperative targets has become a key bottleneck in enhancing space situational awareness capabilities.
In a recent study published in Space: Science & Technology, the team led by Meng Yunhe from the School of Artificial Intelligence, Sun Yat-sen University, proposed a strategy design method for multi-model combined observation of spacecraft based on sequential coalition game theory. Based on the Clohessy–Wiltshire relative dynamics equations, the study constructs four typical close-range operation models, namely the droplet model, the coplanar fly-around model, the non-coplanar fly-around model, and the drifting flight model, and provides the solution functions for the initial motion states that yield stable relative motion configurations. To achieve smooth switching between models, a waypoint trajectory planning scheme and a multi-impulse maneuver strategy are designed based on the minimum integral squared control theory. On this basis, the sequential coalition game theory is introduced for the first time into the multi-model combined observation problem. By constructing a game tree, the algorithm selects the optimal combination of initial motion points and close-range operation models at each stage under minimum fuel constraints, thereby generating an optimal observation strategy sequence. Furthermore, a statistical analysis of the effective observation time under different observation distances and field-of-view angles is conducted. Simulation results demonstrate that the proposed algorithm can successfully generate a multi-model combined observation strategy sequence under minimum fuel constraints; the effective observation time increases with larger observation distances and field-of-view angles, and reducing the model configuration size also contributes to improved observation performance. This study provides a systematic strategy design method for multi-aspect information acquisition of non-cooperative targets, offering significant engineering reference value for space security assessment and on-orbit situational awareness.
First, this study focuses on the problem of multi-aspect observation strategy design for non-cooperative spacecraft and proposes a multi-model combined observation method based on sequential coalition game theory. As a core strategic resource, the geostationary orbit (GEO) hosts a large number of missile early warning and military communication satellites. In recent years, the U.S. GSSAP (Geosynchronous Space Situational Awareness Program) satellites have conducted close-range observation operations on dozens of on-orbit satellites in the vicinity of GEO, rendering the space security situation increasingly severe. Acquiring multi-aspect payload information of non-cooperative targets to infer their functions and mission statuses is of great significance for space security assessment. Fig. 1 defines the LVLH (Local Vertical–Local Horizontal) coordinate frame, which serves as the basis for describing relative spacecraft motion. Fig. 2 illustrates the observation cameras mounted in the ±y directions of the spacecraft; given the constraints of observation distance and field-of-view angle, the effective observation time is defined as the total duration during which the target can be observed while satisfying the prescribed constraints. Since the observation cameras on the spacecraft are fixedly installed, frequent large-angle attitude maneuvers are time-consuming and consume substantial fuel. By designing a combination sequence of multiple close-range operation models, multi-aspect information acquisition of non-cooperative targets can be achieved with minimum fuel consumption. As shown in Fig. 3, through the sequential combination of the four configurations—namely the droplet model, the coplanar fly-around model, the non-coplanar fly-around model, and the drifting flight model—the observing spacecraft can realize multi-aspect imaging.
Second, the study constructs four typical close-range operation models and designs a sequential coalition game solution algorithm. Based on the Clohessy–Wiltshire relative dynamics equations, the analytical solutions of unforced relative motion are derived, and the solution functions for the initial motion states that yield stable relative motion configurations are provided by designing the relative distance and phase angle parameters. The droplet model, characterized by symmetry and re-visit capability, enables fine observation of the target; the coplanar and non-coplanar fly-around models facilitate fly-around observations in different orbital planes; and the drifting flight model achieves close-range observation through multi-impulse control. To achieve smooth switching between models, a waypoint trajectory planning scheme is designed based on the minimum integral squared control theory. On this basis, the sequential coalition game theory is introduced for the first time into the multi-model combined observation problem. Through game tree search, the optimal combination is selected at each stage under minimum fuel constraints, generating an optimal observation strategy sequence.
Finally, the study validates the effectiveness of the proposed method through simulations and analyzes the influencing factors of effective observation time. Fig. 4 presents the three-dimensional relative trajectories of the four-model combined observation, and Table 3 lists the generated sequential coalition observation strategy set: the first stage selects the initial point and the droplet model, the second stage selects the drifting flight model, and the third and fourth stages sequentially select the coplanar and non-coplanar fly-around models. The simulation results demonstrate that the algorithm can successfully generate the optimal combined observation sequence under minimum fuel constraints. Based on the combined observation strategy, the study conducts a statistical analysis of the effective observation time. As shown in Fig. 5, the combined effects of observation distance and field-of-view angle on effective observation time are comprehensively examined; the results indicate that under the same close-range operation model configuration, increasing the observation distance and field-of-view angle significantly enhances target observability and yields longer effective observation time. Given fixed observation distance and field-of-view angle, reducing the model configuration size also contributes to improved observation performance. This study applies sequential game theory to the multi-model combined observation problem of spacecraft for the first time, providing a systematic strategy design method for multi-aspect information acquisition of non-cooperative targets, which offers significant engineering reference value for space security assessment and on-orbit situational awareness.
Spacecraft Proximity Operation Model-Based Sequential Coalitional Observation Game Strategy Design
Fig. 2. Installation diagram of spacecraft observation camera. (A) Payload installation. (B) Field of view.
Fig. 3. Schematic diagram of combined observations based on proximity operation model.
Fig. 4. The relative observed trajectory of multimodel coalitional. (A) Three-dimensional relative observed trajectory. (B) The relative observed trajectory of x-y plane. (C) The relative observed trajectory of x-z plane. (D) The relative observed trajectory of y-z plane.
Fig. 5. Effect of observation distance and field of view (FOV) on effective observation time.
Credit
Space: Science & Technology
United States Space Force says US has weapons in orbit
Copyright Copyright 2026 The Associated Press. All rights reserved
Once a hunting ground for Cold War bragging rights, space has now evolved into a key strategic arena, as states jostle for a military and technological edge.
The United States Space Force confirmed on Monday that the US has deployed weapons into orbit.
"The US has on-orbit space control weapons capable of defending the Joint Force against hostile adversary action," a spokesperson for the force said in a statement.
"Space control encapsulates the mission areas required to contest and control the space domain -- employing kinetic and non-kinetic means to affect adversary capabilities," the statement continued.
It added that "these capabilities can be employed for offensive and defensive purposes.”
'Strategic competitors'
The space domain has become increasingly viewed as a critical component of national security, with much of the world economy relying on space infrastructure such as satellites.
Once a hunting ground for Cold War bragging rights, space has now evolved into a key strategic arena, as states jostle for a military and technological edge.
The US moved to better position itself in 2019, establishing the Space Force to address what the military calls the "growing threat posed by strategic competitors."
Washington is particularly wary of potential threats posed by China and Russia in space.
The Space Force says Beijing and Moscow are developing a range of new systems designed to boost military effectiveness and "end any reliance on U.S. space services," while also "testing and fielding sophisticated counterspace capabilities."
The Chinese military, the force says, believes space will have an important role in future conflicts, "enabling long-range precision strikes and denying other militaries the use of space-based information."
It adds that China has also been developing and operating space and counterspace capabilities as part of a push to modernise its military.
For its part, Russia runs one of the world's largest space programs, and while it has been hampered by funding issues and international isolation, it is still a "capable space actor," the Space Force says.
"Russia views space as a warfighting domain and believes space supremacy will be a decisive factor in future conflicts," it adds.
Could astronauts get cataract surgery on Mars? Scientists test eye implants in space
The research team sent 135 unpackaged artificial lenses to the International Space Station, where they spent around six months exposed to conditions in low-Earth orbit before returning to Earth for analysis.
A trip to Mars could take months. So what happens if an astronaut develops a serious eye problem halfway there?
A team of researchers in the United States sent artificial lenses used in cataract surgery outside the International Space Station to find out whether the implants needed for future operations could survive the journey to places such as Mars.
Researchers behind the study believe someone will need cataract surgery on Mars in his lifetime.
“A Mars transit can require almost a year, and returning to Earth for a vision-limiting cataract, injury, or other surgical eye problem may not be realistic,” said Morgan Micheletti, an ophthalmic surgeon and director of research at Berkeley Eye Center in the US.
“Eventually, treatment will need to happen where the patient is.”
A cataract develops when the eye's natural lens becomes cloudy. During surgery, doctors remove that lens and replace it with a clear artificial one called an intraocular lens.
Doing the same thing millions of kilometres from Earth would require someone capable of carrying out the operation, as well as equipment, sterile supplies and implants that survive the journey.
The idea also grew out of a fascination Micheletti has had since childhood.
“I have been fascinated by space for as long as I can remember,” he said.
“Once I became an eye surgeon, that fascination evolved into a more practical question. Could I perform surgery in space?”
Related
What happened to the lenses in space?
For the project named JAMES, the team sent 135 unpackaged artificial lenses to the International Space Station.
They spent around six months outside the station in three positions, exposing them to different conditions — One faced highly reactive atomic oxygen, another received substantial ultraviolet radiation from the Sun and a third was partly shielded from both.
Another 45 unpackaged lenses remained on Earth for comparison.
After the space lenses returned, a team at the Intermountain Ocular Research Center at the University of Utah examined 61 of them alongside 20 of the lenses kept on Earth.
Most of the space-exposed lenses, 42 out of 61, showed no notable changes.
Of the other 19, eight acrylic lenses developed cracks and surface roughness consistent with erosion from atomic oxygen, while five developed yellow discolouration and let less light through at some wavelengths.
All six light-adjustable lenses, which can be fine-tuned with ultraviolet light after implantation, developed an unusual cobblestone or “bubble-wrap” appearance. Researchers do not yet know why.
That does not mean cataract implants would necessarily be damaged on a journey to Mars, researchers caution.
The lenses were deliberately unpackaged and exposed directly to the harsh environment outside the station to identify how they might fail. In reality, they would travel protected inside a spacecraft.
The next step is to work out how much packaging and shielding they need without adding unnecessary weight and volume.
Related
How realistic is cataract surgery in space?
Cataract surgery beyond Earth remains a distant prospect.
The experiment tested how the artificial lenses withstand space conditions, not whether surgery itself could safely be performed there. Researchers also do not yet know whether the changes found in some lenses would affect vision or make them unusable.
Micheletti next wants to test the machine used in cataract surgery during short periods of microgravity on parabolic flights.
It uses ultrasound and fluid to break up and remove the eye's cloudy natural lens.
If that works, he hopes to move towards longer microgravity tests and eventually a surgical experiment in orbit.
“The progression has to be deliberate. First the materials, then the equipment, then the procedure and, ultimately, the surgery,” he said.
“My long-term hope is to help make the first eye surgery beyond Earth possible.”
Findings from the experiment were presented at the European Society of Cataract and Refractive Surgeons congress in London on Sunday.
Researchers believe it is the first controlled experiment to expose multiple types of modern artificial eye lenses directly to the environment outside the International Space Station and return them to Earth for laboratory analysis.
‘Space: The final frontier’ for cataract surgery!
Intraocular lenses boldly go where none have gone before
European Society of Cataract and Refractive Surgeons
London, UK: An eye surgeon with a passion for space since childhood predicts that as astronauts start to make journeys to the Moon and Mars in the near future, eye surgery in space will eventually become a necessity.
Dr Morgan Micheletti from the Berkeley Eye Center, Houston, Texas, USA, told the 44th Congress of the European Society of Cataract and Refractive Surgeons (ESCRS) today (Sunday) that cataract surgery, in particular, will be needed as people travel through space and stay in space stations for longer periods of time. Therefore, it was vital to know how medical supplies such as intraocular lenses (IOLs) and the other equipment needed for surgery could best be packed, transported, stored and protected from the space environment. [1]
To investigate this, he sent IOLs made of different materials into space as part of the Joint Assessment Of Material Exposure In Space (JAMES) project.
“I believe someone will need cataract surgery on Mars in my lifetime,” said Dr Micheletti. “A Mars transit can require almost a year, and returning to Earth for a vision-limiting cataract, injury, or other surgical eye problem may not be realistic. Eventually, treatment will need to happen where the patient is.
“Astronaut candidates do not need perfect uncorrected vision, and refractive correction or certain prior refractive surgeries can be compatible with selection. More importantly, good vision at launch does not prevent aging, radiation exposure, injury or disease later. As human spaceflight expands beyond career astronauts, the traveller population will also become more diverse.
“This work matters now because these systems must be designed and validated long before the first patient needs them. We cannot wait until someone is on Mars to ask whether the lens, equipment and sterile supplies survived the trip.”
The JAMES project flew 135 unpackaged IOLs to the International Space Station (ISS). They were placed in special carriers that were situated in three different locations on the outside of the ISS. The carriers were called CLAIRE (Carrier for Lens Analysis in Interstellar Research Expeditions), and the three positions on the ISS were Ram (where the lenses were exposed to high atomic oxygen), Zenith (where the lenses were exposed to substantial ultraviolet (UV) from the Sun) and Underdeck (where the lenses were partially shielded from direct atomic oxygen and solar UV by being mounted under the exposure platform).
“This was not intended to recreate how a packaged IOL would normally be shipped to Mars. The purpose was to identify potential failure modes under harsh exposure so we can begin designing better packaging, shielding, storage and material selection strategies. Testing the lenses inside the ISS would not answer the same question because the interior is controlled and pressurised. We want to minimise packaging and, ideally, determine whether these products can be shipped without climate-controlled crew-cabin storage, because mass and volume carry significant costs,” said Dr Micheletti.
On Earth, 45 IOLs were removed from their original packaging and placed in a carrier similar to those for the space lenses, called WILLIAM (Worldly Interface for Lens Logistics and Integrated Astronomical Monitoring). These IOLs remained on earth at room temperature and atmospheric pressure to act as controls. [2]
After approximately six months in orbit, the 135 flight lenses returned to Earth. The current analysis included 61 of those lenses and 20 of the 45 controls stored on Earth: 81 lenses in total. Dr Liliana Werner and her team at the Intermountain Ocular Research Center at the University of Utah, USA, examined them for overall clarity, how well the lenses’ materials remained intact, and whether there were any deposits or changes on the surfaces.
Most of the lenses (42 of 61) exposed to space conditions showed no notable exposure-associated findings when analysed. The other 19 lenses showed three principal patterns:
In the most directly exposed Ram tray, eight of the nine lenses showed cracks and localised surface roughening consistent with early atomic oxygen erosion. All eight were acrylic, including five hydrophobic and three hydrophilic lenses. The ninth lens was silicone and showed yellow discoloration.
Five space-exposed IOLs showed yellow discoloration, including two hydrophobic acrylic and three silicone lenses. Four were in the Zenith tray and one was in the Ram tray. Spectrophotometry showed lower light transmission, particularly between 400 and 500 nanometres.
All six space-exposed light-adjustable lenses, located in the three different positions on the ISS, showed a similar cobblestone or bubble-wrap appearance on both surfaces and along the optic edge. Neither of the two corresponding terrestrial controls showed that appearance. The mechanism remains unknown, and an explanation unrelated to direct space exposure cannot yet be excluded.
Dr Micheletti stressed that this was an exploratory, descriptive study and was not intended to compare different makes or types of lenses, or to test a hypothesis. The analysis covered a selected subset of the payload. Sample sizes were small and uneven, and in some positions in the carriers there was only one lens of a given model. The lenses were deliberately unpackaged, and handling or environmental contamination could not be fully excluded. The control lenses did not undergo launch, return or flight handling, which limits attribution of the changes specifically to external exposure. Beyond transmission spectrophotometry, image-quality, mechanical and clinical-performance testing has not yet been completed. He said the findings should not be used to rank manufacturers or lens models and do not imply a safety concern for routine cataract surgery on Earth.
Dr Micheletti said: “The findings suggest that lens material and exposure location may influence the changes observed. Packaging, shielding and storage were not compared in this experiment and are the next protective strategies we need to test. The engineering challenge will be providing enough protection without adding unnecessary mass because every kilogram sent into space carries a cost.”
He hopes to investigate how a phacoemulsification system [3], the ultrasound and fluidics system [4] used in cataract surgery, performs during the brief periods of microgravity produced by parabolic flights. If that work is successful, the longer-term path could include sustained microgravity testing and, eventually, an in-orbit surgical experiment.
“The progression has to be deliberate: first the materials, then the equipment, then the procedure and, ultimately, the surgery. My long-term hope is to help make the first eye surgery beyond Earth possible,” he said.
“I have been fascinated by space for as long as I can remember. In second grade, I did a project on the Apollo missions and had the opportunity to interview Gene Kranz, the NASA flight director best known for his leadership during Apollo 13. That experience stayed with me. Once I became an eye surgeon, that fascination evolved into a more practical question: could I perform surgery in space?”
Published clinical reports have described astronauts and other spaceflight participants who flew with implanted lens devices. Those implanted devices were protected by the eye and body. What had not been studied before was how multiple modern IOL materials respond when directly exposed outside the ISS to vacuum, temperature cycling, solar ultraviolet radiation, ionising radiation and atomic oxygen. JAMES addresses preimplantation transport and storage, not the performance of an IOL already implanted in an eye. To the investigators’ knowledge, JAMES is the first controlled experimental study to expose multiple modern IOL materials directly to the external low-Earth-orbit environment outside the ISS and return them for laboratory analysis.
Dr JoaquÃn Fernández, ESCRS Secretary, CEO of Qvision and Medical Director of Andalusian Ophthalmology Institute at Vithas Hospitals, AlmerÃa, Spain, who was not involved with this research, said: “As more and more people go into space and for longer periods of time, it is likely that eye surgery will be required at some point. Therefore, it’s imperative that we understand how lenses and other materials required for surgery behave when exposed to environments beyond the Earth’s atmosphere. The research presented today is forward-thinking and will, undoubtedly, play an important role in our preparations for deep space exploration.”
(ends
[1] Abstract PP15.04, ‘The Joint Assessment Of Material Exposure In Space (JAMES): Laboratory analyses of Intraocular Lenses (IOLs) after low-Earth-orbit exposure on the exterior of the International Space Station (ISS)’, by Morgan Micheletti et al,
[2] Dr Micheletti says the mission is very personal to him. JAMES is named after his middle child, the CLAIRE carriers and the Earth-based control at WILLIAM are named after his other two children.
[3] Phacoemulsification is a cataract surgery method in which the internal lens of the eye which has developed a cataract is emulsified with the tip of an ultrasonic handpiece and aspirated from the eye. A balanced salt solution replaces the aspirated fluids to maintain the volume of the anterior chamber during the procedure. This procedure minimises the incision size and reduces the recovery time and risk of surgery-induced astigmatism.
[4] The management of fluid inflow and outflow during cataract surgery.
Method of Research
Experimental study
Subject of Research
Not applicable
Article Title
The Joint Assessment Of Material Exposure In Space (JAMES): Laboratory analyses of Intraocular Lenses (IOLs) after low-Earth-orbit exposure on the exterior of the International Space Station (ISS)
Article Publication Date
13-Sep-2026
COI Statement
J. M. Micheletti, Md Grant / Research support with: Bausch & Lomb, Carl Zeiss Meditec, STAAR Surgical, Consultant with: Alcon, BVI, Bausch & Lomb, Carl Zeiss Meditec, Johnson & Johnson Vision, Lenstec, RxSight, STAAR Surgical, L. Werner: None declared
