Category: English

Source: The Conversation – USA – By Houlong Zhuang, Associate Professor of Engineering, Arizona State University

From hypersonic aircraft to nuclear-powered submarines, many of today’s most advanced defense systems rely on a special class of materials known as refractory alloys. This class refers to metals that do not melt or weaken easily, even in extreme heat.

An alloy is a material made by combining two or more metallic elements to achieve properties no single metal can offer on its own – greater strength, for example, or better resistance to corrosion. Refractory alloys are based on elements such as tungsten, niobium and molybdenum, which have some of the highest melting points of any metals.

Their atoms are held together by strong chemical bonds and arranged in a stable crystal structure that resists deforming, even at extreme temperatures. Where conventional alloys begin to soften and slowly deform under constant stress, refractory alloys retain their strength, making them essential for components exposed to extreme heat, stress and radiation.

Most refractory alloys in service today were designed decades ago. They predate modern 3D printing of metal parts, also called additive manufacturing, and artificial intelligence.

To execute metal 3D printing, a laser or electron beam melts successive thin layers of metal powder.

This builds up a 3D part directly from a computer model by adding material layer by layer, rather than using molds or removing material from a solid block. 3D printing allows shapes that are impossible with traditional manufacturing methods. However, many current refractory alloys are difficult or impossible to manufacture reliably using these techniques.

This mismatch can slow the domestic production of new parts. To help address these manufacturing and supply-chain challenges, our team of materials researchers at Arizona State University and UNSW Sydney has formed a new international collaboration to redesign high-temperature alloys.

Old alloys in a new manufacturing world

Additive manufacturing allows defense and aerospace manufacturers to produce complex components locally, on demand and with far less material waste. In principle, it is ideal for producing replacement parts for aircraft, spacecraft and naval systems.

In practice, many refractory alloys crack, warp or develop internal defects when 3D-printed. Their compositions were optimized for casting or forging, not for the rapid melting and solidification involved in laser-based printing. In 3D printing, a laser melts and resolidifies metal thousands of times in quick succession, creating steep temperature gradients that generate enormous internal stresses. Several key refractory metals are brittle at room temperature and cannot absorb those stresses without cracking.

Redesigning these alloys using traditional trial-and-error methods would take decades.

Teaching computers to design new metals

Our alternative approach uses reinforcement learning, a form of artificial intelligence best known for training computers to master games such as Go or chess.

Designing a new alloy is a bit like mixing ingredients for a recipe, but at the atomic level. Instead of planning moves on a board, the AI system explores thousands of possible alloy recipes – for example, different combinations of chemical elements. Even tiny changes in the ingredients can completely change how the final material behaves.

The AI evaluates each candidate virtually against multiple criteria, including strength at temperatures above 1,800 degrees Fahrenheit (1,000 degrees Celsius) and resistance to damage caused by reacting with oxygen at high heat, as well as weight, cost and, crucially, whether it can be reliably 3D-printed.

Alloys that should perform well are rewarded, while those that fail are discarded. Over repeated cycles, the system learns which chemical combinations work best.

We can then manufacture and test the most promising AI-designed alloys in the laboratory. Their real-world performance feeds back into the model, steadily improving its predictions.

Strategic benefits beyond the laboratory

The implications of our research extend beyond the lab.

For defense agencies, faster materials development means quicker deployment for next-generation engines, hypersonic vehicles and systems that protect against heat. AI-designed alloys can be optimized for strength, heat resistance and manufacturability. For example, NASA’s GRX-810 alloy, designed with computational methods and 3D-printed, is 1,000 times more durable at high temperatures compared with traditional alloys.

Traditional manufacturing of refractory metals wastes up to 95% of the raw material through machining – removing unwanted material to create the precise shape – but 3D printing can bring that figure close to zero.

Our work is an international collaboration. At Arizona State University, the focus is on AI-driven computational design. UNSW Sydney’s facilities allow for high-temperature testing by looking at the metal’s microstructure and conducting additive manufacturing under realistic conditions.

Challenges still ahead

This approach is not without hurdles. One of the biggest is data scarcity: AI models learn from existing experimental results, and for refractory alloys, that data is limited. Far fewer alloys in this class have been systematically tested, compared with more common materials like steel or aluminum.

There are also practical constraints. Refractory metal powders suitable for 3D printing are expensive and difficult to source, and scaling up from small laboratory samples to full-sized components is difficult. An alloy that performs well as a thumbnail-sized test sample may behave very differently when printed as a large, complex part.

Finally, AI predictions must always be validated experimentally – and those experiments are costly and time-consuming. The system does not eliminate the need for rigorous physical testing.

A new model for defense-focused research

Our collaboration is in its early stages. We are currently building the AI model and assembling the experimental databases it will learn from. Later this year, the first candidate alloy compositions will be selected for 3D printing and laboratory testing. The results will feed back into the model.

We are also working with defense research agencies to ensure our work aligns with real-world needs and to lay the groundwork for larger-scale programs.

In an era where technological advantage increasingly depends on speed and adaptability, reimagining how we design the metals behind defense systems can improve the systems themselves.

Houlong Zhuang receives funding from Security and Defence PluS Alliance.

Vitor Rielli receives funding from Security and Defence PluS Alliance

– ref. AI and 3D printing help researchers create heat- and pressure-resistant materials for aerospace and defense applications – https://theconversation.com/ai-and-3d-printing-help-researchers-create-heat-and-pressure-resistant-materials-for-aerospace-and-defense-applications-273687

Source: The Conversation – USA – By Marcos Fernandez Tous, Assistant Professor of Space Studies, University of North Dakota

Throughout February 2026, people at the Kennedy Space Center got to witness an exciting sight: NASA’s behemoth Space Launch System rocket, SLS, standing on the launch pad, aimed toward the sky. The launch system has been key to the Artemis program – an ambitious series of missions intended to culminate in a sustained human presence on the Moon. NASA had initially planned to launch the second Artemis mission, which would take a crew of four people around the Moon, in February.

But as anticipation for launch built, an issue with the liquid propellant arose. A few days later, the SLS faced another problem, this time with the rocket’s upper stage, and had to roll back from the pad.

I’m an aerospace expert who is deeply passionate about aerospace technology and what it means for the U.S. and humanity’s future. I’ve been following the Artemis program’s timeline – February 2026 has represented a pivotal moment for U.S. spaceflight. Artemis II faced a number of delays, and NASA officials announced a shake-up of the larger program’s timeline.

Springing leaks

It started on Feb. 2, during Artemis II’s first wet dress rehearsal. During this major test, engineers assemble all components of the Space Launch System and fill its tanks with a combined 700,000 gallons of super-cold liquid hydrogen and liquid oxygen. These liquids act as the propellant for the rocket during launch.

During the test, the team detected a hydrogen leak at the interface of a 33‑foot-high (10 meters) service mast, the removable structure that brings the hydrogen and oxygen to the tank. They attributed the cause of the issue to moisture accumulated in the Teflon seal of two interfaces between that mast and the vehicle’s tank.

On the following day, NASA decided to postpone the launch until March 6. A new wet dress rehearsal would take place on Feb. 19 to verify everything was working as expected.

On the day of the second wet dress rehearsal, hydrogen operations proceeded smoothly, seemingly confirming plans for a March launch for Artemis II. Engineers at NASA likely breathed a sigh of relief, but they did so too early. A couple of days later another problem surfaced: They found the exploration upper stage was leaking helium. This upper stage of the rocket kicks in above 62 miles (100 kilometers), once the core stage expends all its propellant.

Because helium is essential for pressurizing cryogenic tanks and for purging the pipelines that will carry highly reactive liquid oxygen, the leak raised concerns.

Notably, these issues echoed the challenges SLS encountered ahead of its first launch for the Artemis I mission in 2022. Artemis I launched nearly six years after NASA’s original target date, ultimately accumulating 25 scrubbed or delayed launch attempts. Recurring hydrogen leaks in the tail service mast umbilical – a very similar issue – caused several of these delays.

Trouble with the SLS

On Feb. 25, the same day SLS rolled back to the vehicle assembly building for more work, NASA’s independent Aerospace Safety Advisory Panel released its annual report. This panel began in the aftermath of the January 1967 Apollo command module fire that claimed the lives of three astronauts, and NASA headquarters takes its assessments very seriously.

Citing the problems encountered on Artemis I and II, the panel warned of elevated risks for Artemis III, which planned to land on the Moon. They strongly recommended NASA restructure the program to reduce the likelihood of similar issues on future missions.

On Feb. 27, NASA made a major announcement: Artemis IV, scheduled for 2028, would now include a lunar landing. Artemis IV would then overlap with another landing planned in the same year, Artemis V.

NASA also confirmed that it plans to replace the exploration upper stage – the source of the helium leak – with a different upper stage known as the interim cryogenic propulsion stage. While the exploration upper stage was designed to use four engines, the interim cryogenic propulsion stage relies on a single engine.

The interim cryogenic propulsion stage previously flew on Artemis I, after which NASA intended to transition to the exploration upper stage for future missions. With the restructuring, however, the exploration upper stage program has been canceled, and NASA is returning to the interim cryogenic propulsion stage instead. With this change, Artemis appears to be going back to the basics and returning to simpler, proven hardware.

While Artemis II will not launch before April, the plan for the mission itself remains the same: It will still fly around the Moon.

But this new situation poses a question: If Artemis IV will now carry out the lunar landing, what will become of Artemis III, which had originally been planned as humanity’s return to the Moon? In essence, NASA is accelerating the schedule by adding more launches and tests before the first lunar landing attempt, and these changes are not necessarily to Artemis’ detriment.

A new timeline

NASA aims to increase the cadence of launches up to every 10 months starting in April 2026, incorporating fewer changes from mission to mission each time. This approach reduces technological uncertainty and stands in sharp contrast to the more than three‑year gap between the 2022 launch of Artemis I and the potential 2026 launch of Artemis II.

Artemis III will now become a tightly focused rehearsal mission lasting 30 days. NASA will test each mission component independently rather than checking them all together as a unit. Instead of visiting the Moon, Artemis III will remain closer to Earth.

NASA Administrator Jared Isaacman explained to CBS on Feb. 27 that Artemis III will launch the Orion spacecraft, which holds the astronaut crew, into low Earth orbit, where it will dock with one or both lunar landers – Blue Origin’s Blue Moon lander and SpaceX’s Human Landing System.

The Human Landing System will be a modified version of SpaceX’s Starship, the company’s enormous, superheavy spacecraft. The docking maneuver will help NASA confirm that the lander can handle the forces involved in connecting with Orion in space – essentially checking that the structure behaves as expected and can safely support the crew and their equipment.

Isaacman also pointed out that Artemis III may allow for NASA to test out the new spacesuit Axiom Space is designing for forays outside of the spacecraft.

The mission may also test navigation, communication, propulsion and life‑support systems. Interestingly, this series of tests aligns Artemis III more closely with the historical role of Apollo 7, which focused on evaluating the command and service module in Earth orbit.

In short, the new plans reshape Artemis III into a proof‑of‑concept mission intended to validate several critical systems before the two lunar landings planned for 2028 with Artemis IV and V. If successful, this approach should greatly improve the reliability of the missions that will finally return humans to the lunar surface. The revised timeline creates more opportunities to test and troubleshoot all the systems required for a safe landing.

It will also keep the missions more straightforward. With the same configuration across all missions, the tests will build on each other.

For now, you will need to wait a bit longer to watch humans walk in the Moon’s south pole region, where icy craters may hold clues to the early history of our solar system. But if February 2026 sets the tone, this next chapter will be anything but dull. Fasten your seat belts.

Marcos Fernandez Tous does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

– ref. With Artemis II facing delays, NASA announces big structural changes to the lunar program – https://theconversation.com/with-artemis-ii-facing-delays-nasa-announces-big-structural-changes-to-the-lunar-program-277169

Source: The Conversation – USA – By Eric Horstick, Associate Professor of Biology, West Virginia University

Being right- or left-handed is a familiar fact about yourself you likely don’t think about much on a day-to-day basis. However, your handedness affects how you interact with the world.

For many people, it determines how they brush their teeth, use tools, play sports, write, eat and much more. Simply try to enjoy a bowl of soup or sign your name with your nondominant hand to appreciate the impact a hand preference can have on your daily life.

Interestingly, this behavioral asymmetry is not unique to humans. Preferences for using the right or left hand, paw or eye exist in most species. For example, many primate species have individual left- or right-hand preferences for manual tasks. Similarly, different bird species have varying eye preferences for distinct visual tasks. Even the largest animal alive, the blue whale, shows a preference for the direction of its rolls during feeding. This inherent and often-overlooked feature of behavioral asymmetry is a widespread phenomenon in the animal kingdom.

The universality of behavioral asymmetry suggests that having an assigned hand, eye or other preference is beneficial. But depending on one hand for so many important tasks means that a single injury could be devastating. This paradox poses an important question: Why would having handedness be better for survival than not?

Insights from fish ‘handedness’

To address this question, scientists have tried to understand the genetics of handedness. While large-scale genetic studies in humans have identified dozens of genes associated with handedness, researchers also found that genetics alone only partially accounts for whether someone is left- or right-handed. This means behavioral asymmetry like handedness is likely the product of complex interactions between genetics, development and the environment.

For the past six years, my research lab has been interested in understanding behavioral asymmetry and how such behaviors get encoded in the brain. We primarily use larval zebrafish to explore the neural basis of behavioral asymmetry. These animals have transparent bodies and rapidly develop into adults in just a few days, making them ideal models to study. Additionally, the genetics and brain structure of zebrafish are highly similar to those of humans.

Fish have a form of handedness called motor asymmetry, which involves sustained periods of turning in the same direction. I had previously found that when light was cut off, larval zebrafish start circling in a leftward or rightward direction, sometimes for up to a minute or more. The fish would continue to preferentially turn in that same direction over the course of hours, days and even weeks, looking for a light source. This meant that vision drove their motor asymmetry.

Students in my lab recorded the zebrafish’s neural activity in response to loss of environment light – the trigger for motor asymmetry. They found a subset of approximately 60 neurons in the thalamus – a region of the brain that is evolutionarily conserved among vertebrates and involved in relaying sensory information – was functionally linked to motor asymmetry. Removing these neurons eliminated this motor asymmetry, suggesting a potential neural basis for where behavioral asymmetry is established in the fish brain.

When my lab repeated our experiments on five additional species of larval fish from around the world, we found similar motor asymmetry in response to light. Much like handedness in primates, it appears that handedness in fish is likely more of a rule than an exception.

However, we did find one exemption: the Mexican tetra, also known as cavefish. These animals are found in perpetually dark cave environments and are naturally blind. In collaboration with our colleagues at the Duboué Lab at Florida Atlantic University, we found that these animals showed no motor asymmetry.

These findings suggest that the universal nature of behavioral asymmetries are likely crucial responses to common challenges that different organisms encounter.

Behavioral asymmetry may solve challenges

Hurting your dominant hand does more than just ruin your softball or ultimate frisbee game. Handedness is associated with broad neural asymmetries in the brain that are linked to performance in language comprehension and working memory tasks. In addition, having atypical handedness – such as preferring different hands for different activities – is associated with a range of neurological conditions, including autism and attention-deficit/hyperactivity disorder.

Understanding why animals have behavioral asymmetries offers clues about how the environment influences broader cognitive function. If environmental challenges indeed drive handed behaviors, what problems does motor asymmetry solve for fish?

In nature, animals often circle when searching for something, such as a food source. For larval zebrafish, light is an important resource for their ability to see and capture prey. When we placed a light source at varying locations around them, the larval zebrafish start circling to quickly navigate into illuminated environments conducive to hunting. Based on our work, we hypothesize that the asymmetries in fish that allow them to search more efficiently work in parallel ways to those of other animals, like eye movement in birds or language comprehension in people.

Prior research has suggested that brain asymmetries improve cognitive performance by reducing competition between the two sides of the brain. Our work supports these hypotheses by showing how, for zebrafish, motor asymmetry provides a default response to find light and efficiently catch a needed snack.

With a helping hand from fish handedness, researchers are getting a clearer idea of the universality of behavioral asymmetry and how the environment may be shaping the brain so that one hand, or fin, provides an advantage in daily life.

Eric Horstick receives funding from the National Institutes of Health and National Science Foundation.

– ref. I study why zebrafish larva prefer to circle left or right, to understand how and why human brains encode right- and left-handedness – https://theconversation.com/i-study-why-zebrafish-larva-prefer-to-circle-left-or-right-to-understand-how-and-why-human-brains-encode-right-and-left-handedness-274578

Source: The Conversation – USA – By Deyanira Nevárez Martínez, Assistant Professor of Urban and Regional Planning, Michigan State University

A bureaucratic shift in Washington is threatening to undo years of progress in Detroit’s fight against homelessness, potentially forcing thousands of the city’s most fragile residents back onto the streets.

In November 2025, the U.S. Department of Housing and Urban Development revised how it would allocate funding through its flagship homelessness program, the Continuum of Care.

The change reduced the share of funding available for permanent subsidized housing and increased funding for transitional short-term housing.

HUD officials described the shift as a move away from a “housing first” model toward a “treatment first” approach that emphasizes participation in services, such as drug addiction disorder treatment, before or alongside housing placement.

The administration has argued that this promotes self-sufficiency. Critics contend that stable housing is the foundation that makes treatment and recovery possible.

The policy revision has been challenged in court by 20 states, including Michigan, as well as city and county governments and advocacy organizations. They argue it could destabilize individuals and families across the country, state and here in Detroit.

I am an urban and regional planning scholar who studies housing policy, and I serve on the research council of the National Alliance to End Homelessness.

In December 2025, I joined 77 other homelessness researchers who sent a letter to Congress analyzing the likely impacts of HUD’s revised funding approach. That analysis draws on decades of peer-reviewed research evaluating which housing interventions reduce homelessness and which do not.

That same month, a federal judge issued a preliminary injunction that temporarily pauses HUD’s efforts to shift funding away from permanent supportive housing.

HUD officials stated that the agency intends to apply the changes in future funding rounds, once the order is no longer in effect.

Homelessness in Detroit

Detroit’s homelessness crisis is both long-standing and worsening.

The number of people who experience homelessness in Detroit, Hamtramck and Highland Park increased by about 16% from 2023 to 2024, with roughly 1,725 people experiencing homelessness on a single January night, including hundreds of families. Children in particular have been hit hard by this crisis. One data snapshot shows 2,579 children reported being doubled up, staying in a shelter, staying in a hotel or motel or being unsheltered. This was a record number for the Detroit Public Schools Community District.

While permanent supportive housing has strong outcomes for those who receive it, overall homelessness has continued to increase due to rising rents, economic instability and the limited housing supply, which has historically outpaced the number of available supportive units.

Detroit’s homelessness response system is coordinated through the federally funded local Continuum of Care led by the Homeless Action Network of Detroit.

In recent years, Detroit has taken steps to strengthen coordination, expand shelter capacity and increase housing placements. But the system heavily depends on federal funding to provide permanent supportive housing.

What could change in federal homelessness funding

The Continuum of Care program began in 1994 and was later codified in 2009 by the Homeless Emergency Assistance and Rapid Transition to Housing Act. It is the largest federal funding stream dedicated to addressing homelessness in the United States.

Last year alone, Detroit received US$40 million from the HUD program.

Those funds pay for emergency shelters, transitional housing and rapid rehousing programs – which provide temporary rental assistance and the assistance of a social worker, without preconditions – and permanent supportive housing.

Like other cities nationwide, Detroit has built its homelessness response system around HUD’s funding priorities.

For more than a decade, HUD has emphasized permanent housing. A strong body of evidence shows that stable housing leads to better long-term outcomes than temporary programs.

Prior Continuum of Care funding cycles allocated roughly 85% to 90% of funds to permanent housing, according to the National Alliance to End Homelessness.

The revised funding priorities announced in late 2025 would substantially reduce that share and redirect funding toward transitional housing and short-term interventions.

According to the Homeless Action Network of Detroit, this means that Detroit area providers could go from about $34 million per year allocated for permanent supportive housing under the current allocation to no more than about $11 million under the new priorities.

Local advocates warn that capping permanent housing at roughly 30% of Continuum of Care dollars would drastically reduce the number of supportive units available and place hundreds of households at risk of returning to homelessness.

Why permanent supportive housing matters

Permanent supportive housing is one of the most rigorously studied homelessness interventions in the United States.

It is an evidence-based intervention that provides long-term rental assistance paired with voluntary supportive services for people who have experienced chronic, or repeated, homelessness, particularly those with disabilities or chronic health conditions.

Under the current Continuum of Care framework, households typically pay no more than 30% of their income toward rent, with the subsidy covering the remainder. Assistance can continue as long as eligibility criteria are met.

Programs also offer staff to help with coordination of health care and behavioral health services and assistance identifying and applying for relevant benefits to promote long-term housing stability. Tenants hold standard leases and have the same legal protections as other renters.

Research shows that permanent supportive housing using a housing-first approach consistently reduces homelessness and improves health outcomes for people with disabilities.

Greater investment in permanent supportive housing is also linked to reductions in chronic homelessness, meaning individuals or families who have been homeless for long periods or repeatedly over time.

A long-term study published in Social Service Review in 2014 found that communities that increased permanent supportive housing capacity experienced measurable declines in chronic homelessness over time.

Local data from the Detroit Continuum of Care indicate that at least 160 new permanent supportive housing units have been made available in the past year, and another 235 units are projected for 2026. These units help people exit homelessness and maintain stable homes amid rising rents and affordability challenges.

How transitional housing compares

Transitional housing typically requires residents to participate in supportive services or programming as a condition of stay. This can include regular meetings with a social worker, employment readiness classes, substance use treatment or financial literacy workshops, for example.

The model is often used for survivors of domestic violence or young adults aging out of foster care. While transitional housing can provide short-term stability and support during these transitions, it differs from permanent supportive housing in that it is time-limited and may require program compliance as a condition of continued residency. Transitional housing placements typically last from about six months up to two years.

However, research consistently finds that transitional housing is less likely than permanent housing to produce long-term housing stability. This is particularly the case for families and people with disabilities.

HUD’s Family Options Study in 2016 found that families offered permanent housing experienced significantly better long-term housing stability than those offered transitional housing, despite transitional housing costing more per household.

Follow-up research conducted by the Urban Institute, a nonprofit organization that studies economic policy, similarly found that many families who leave transitional housing once their time limit expires struggle to maintain stable housing. These findings are especially relevant for individuals with disabilities, chronic illnesses or mental health conditions, all groups that are typically prioritized for permanent supportive housing.

Why Detroit is especially vulnerable

Research shows that housing instability increases reliance on emergency services such as shelters, hospitals and public safety systems. This drives up taxpayer costs and additionally strains already overextended local services.

Detroit area homelessness service providers are pushing back against the potential federal changes, which they identify as “radical.”

In response, many organizations are turning to state and philanthropic partners for support while continuing to develop housing locally to help offset possible reductions in federal funding.

Deyanira Nevárez Martínez has received funding from the State of Michigan, the Latino Policy and Politics Institue at UCLA, the Institute for Research on Poverty at the University of Wisconsin-Madison, and the Freedom Together Foundation (formerly the JPB Foundation). She is an Assistant Professor of Urban and Regional Planning at Michigan State University and is an elected member of the Lansing City Council representing ward 2.

– ref. Housing First helps people find permanent homes in Detroit − but HUD plans to divert funds to short-term solutions – https://theconversation.com/housing-first-helps-people-find-permanent-homes-in-detroit-but-hud-plans-to-divert-funds-to-short-term-solutions-274272