2026-08-31 20:00:01
In a display case on the lower level of the Faraday Museum at the Royal Institution in London, there’s an unassuming stack of gray metal discs and blotting paper. It’s not at all obvious that this humble object is the starting point of today’s multibillion-dollar global battery industry. The object’s invention in 1799 grew out of a disagreement that Alessandro Volta—the Italian physicist for whom the unit of measurement for electrical potential is named—had with his friend Luigi Galvani over a dead frog.
Galvani was a well-respected Italian physician. In the 1770s, he began investigating the use of electricity to stimulate the muscles of dissected frogs. Armed with an electrostatic generator and an early type of capacitor called a Leyden jar, he was able to create a charge, store it, and then zap his animal specimens at will. He was intrigued when the frog legs twitched as if they were still alive. He spent the last three decades of the 18th century studying the phenomenon, and in 1791, he published De viribus electricitatis in motu musculari commentarius (Commentary on the Effect of Electricity on Muscular Motion).
Luigi Galvani spent decades investigating what he believed to be a natural electric force emanating from animals. Universal History Archive/Getty Images
Galvani saw the frog as embodying an “animal electricity,” an innate vital force that activated nerves and muscles, similar to what had been observed in (living) electric eels and torpedo rays. For Galvani, the frog was an electrical machine analogous to a Leyden jar. The brain was the source of the electrical charge; the nerves conducted the electrical fluid; and the muscles stored opposite charges. The illustrations in his 1791 book are fabulous—frog legs spread all over his laboratory table!
Galvani was wrong in thinking that his frogs were electrical machines, but he was right that the muscle contractions were caused by electric signals.SSPL/Getty Images
At first, Volta, chair of physics at the University of Pavia, concurred with his friend. But after beginning his own experiments, he concluded that Galvani was wrong and that the frog generated no electricity at all. He thought of the frog as nothing more than an electroscope, an instrument to indicate the presence of an electrical charge. Volta posited that the source of the charge Galvani observed came from two different metals in contact with the frog. He termed this “metallic electricity.”
Alessandro Volta came to disagree with Galvani’s theory of animal electricity.Apic/Getty Images
To prove his point, Volta created an “artificial electric organ.” He stacked alternating discs of copper and zinc, separated by cardboard, blotting paper, or cloth soaked in brine or acid. When the top and bottom plates were connected, an electric current flowed through the stack. As opposed to a Leyden jar, which is essentially a capacitor that can store an electric charge and release it in a brief powerful discharge, his stack of discs generated its own electricity through a chemical reaction and delivered a sustained low-current output.
Volta didn’t publicly demonstrate or announce his artificial electric organ until after Galvani died in 1798. But when he finally did, in 1799, it immediately began upending science. Just six weeks after Volta wrote to the Royal Society about his invention, the English scientists William Nicholson and Anthony Carlisle used a voltaic pile to run a current through water to separate it into hydrogen and oxygen. They had discovered chemical electrolysis. Humphry Davy later used a large voltaic pile to isolate a number of elements, including potassium, sodium, calcium, strontium, and barium. Early piles petered out after a few hours. Users who stacked up more metal discs to make more powerful piles found the weight of the discs squeezed out the moisture in the paper or cloth.
Invented in 1799, Volta’s “artificial electric organ” (later known as the voltaic pile) was the first battery. Volta presented this one to Michael Faraday in 1814.Royal Institution of Great Britain/Science Source
One of the most enthusiastic users of the voltaic pile was Galvani’s nephew, Giovanni Aldini, who spent much of his career defending his uncle’s ideas. Aldini created spectacles across Europe in which he used voltaic piles to shock the carcasses of livestock and, occasionally, the bodies of recently executed convicts. Vivid descriptions in the popular press, as well as Aldini’s own writings, raised the question of whether electricity could bring the dead back to life. Mary Shelley provided her answer in her 1818 novel, Frankenstein; or, The Modern Prometheus. In an introduction to an 1831 edition, Shelley cites galvanism as one of her inspirations for the monster’s reanimation process.
Scientists and historians share a common trait: They like stories with clear winners and losers. The narrative of competition helps drive a narrative of progress that makes it look like humanity is always moving forward. In the case of Galvani and Volta, Volta is usually depicted as the clear winner in the debate over animal versus metallic electricity. The Encyclopedia Britannica goes as far as to write that “with his announcement of the first electric battery in 1800, victory was assured for Volta.”
But both science and history are more nuanced than that. In fact, Galvani and Volta were both partially right and partially wrong. There was no universal force of animal electricity, but Galvani was correct that electrical signals caused muscle contractions, which he discussed in his anonymous 1794 publication Dell’uso e dell’attività dell’arco conduttore nella contrazione dei muscoli (On the Use and Activity of the Conductive Arch in the Contraction of Muscles). Volta was right to push back on Galvani’s animal electricity theory, but he was wrong that electrophysiological effects require two different types of metal, or any metal at all; the circuit in the voltaic pile was closed by the wet paper or cloth.
It seems a little presumptuous for the Encyclopedia Britannica to declare Volta the winner and Galvani the loser. Volta definitely thought his friend was wrong, but he waited until after Galvani’s death to make his views public. It’s closer to the truth to say they were both genuinely curious to understand the nature of electricity. In the process, they unknowingly helped develop different fields of inquiry: electrophysiology for Galvani and electrochemistry and battery science for Volta.
Such an outcome is actually quite common in scientific disagreements. For example, Isaac Newton’s dispute with Christiaan Huygens over the nature of light—did light consist of particles, or corpuscles, as Newton termed them, or waves, as Huygens contested—breaks down today into quantum optics and classical optics. Similarly, Louis Pasteur’s and Justus von Liebig’s debate over fermentation (microorganisms versus chemical decomposition) led to two complementary fields: microbiology and biochemistry.
Maybe instead of looking for winners and losers, we would be better off expanding our horizons and considering the multiple paths of inquiry and discovery. Writing in 1816, toward the end of his career, Volta graciously acknowledged Galvani’s pioneering work, saying “it contains one of the most beautiful and surprising discoveries and the germ of many others.” What new revelations are waiting to develop out of today’s scientific debates?
Part of a continuing series looking at historical artifacts that embrace the boundless potential of technology.
An abridged version of this article appears in the September 2026 print issue as “The First Battery.”
On 20 March 1800, a year and three months after the death of Luigi Galvani, Alessandro Volta wrote a letter (in French) to Joseph Banks, president of the Royal Society, describing his invention of an artificial electric organ. It was read before the Society on 26 June and published in Philosophical Transactions on the last day of that year as “On the electricity excited by the mere contact of conducting substances of different kinds.”
The Smithsonian Institution Libraries used their rare books in the online exhibit The Body Electric, which has more information on both Galvani and Aldini.
The website of the Whipple Museum in Cambridge, England, has a number of pages devoted to frogs, including a very informative description of the role frogs played in Galvani’s experiments and how those led to Volta’s work.
2026-08-29 23:35:01
One day in 1982, Joseph “Rod” Canion and two colleagues from Texas Instruments sat down at the House of Pies in Houston and used a napkin to sketch out what would become Compaq’s portable PC. In 1996, Felix Zandman, founder of Vishay Intertechnology, dined at Husker Steak House in Columbus, Neb., grabbed a napkin and drafted a design for a power metal strip resistor, which became crucial to power-management components in industrial, automotive, and consumer applications. Now that wispy piece of paper resides at the Smithsonian’s National Museum of American History. Perhaps most famously, Robert Metcalfe, working at Xerox PARC in 1973, roughed out some early designs for what would become the [?] Ethernet, though contrary to popular belief, no napkin was involved.
Yet another napkin was pressed into service last year, when Kurt Polzin, chief engineer of the space nuclear propulsion project at NASA’s Marshall Space Flight Center, met Robert Schleicher of General Atomics Electromagnetic Systems at a conference and started talking about nuclear rocket design.
“They did the classic let’s-sketch-out-an-idea-on-a-napkin,” says IEEE Spectrum’s Special Projects Editor and our in-house spaceflight expert Stephen Cass. “This rocket engine is still at the paper-planning stage, which, to be fair, is where most of NASA’s humans-to-Mars planning has been for the last 60 years.”
Meanwhile, the world’s richest person is pushing for humans to colonize Mars in time for him to escape our hospitable blue marble for a completely barren red planet. One big problem with this idea: It takes a long time in hostile space to get there.
“Here’s our napkin. Noodle on this with us and tell us what you think.” —Stephen Cass
There’s an old saw, mostly used in the context of road safety, that speed kills. But when it comes to sending humans on interplanetary missions, the faster the better. As Cass pointed out, “Once you get outside the Van Allen belts, there’s so much natural radioactivity—that’s the real killer.” Nuclear electric propulsion could both minimize launch costs and the time fragile human bodies are subjected to microgravity and radiation. And that makes a synchronal bimodal nuclear engine that could both power and propel a spaceship an attractive alternative to a conventional rocket.
Polzin and Schleicher think their nuclear engines could halve the time it takes to get to Mars. There may be ways to tweak the design to go even faster and further. But for now, the idea sits on the drawing board, awaiting feedback and refinement.
“They’re pulling together a lot of fairly mature technology,” says Cass, who edited Polzin and Schleicher’s article, “A Reimagined Nuclear Rocket.” “Electric propulsion is mature. Nuclear thermal propulsion is not, but thanks to [previous efforts], we have a good idea how to do it. The new part is merging them together, and that of course throws up its own challenges.”
Thanks to Cass and illustrator John MacNeill, Polzin and Schleicher’s idea has moved from a napkin to the pages of this month’s issue. Says Cass, “The whole point of the article is to say, ‘Here’s our napkin. Noodle on this with us and tell us what you think.’” We invite you to do so in the comments beneath the web version of this article. Or do it the old-fashioned way and mail the authors your own napkin.
2026-08-29 02:00:04
While walking to school as a child, Jernej Barbič would marvel at how beautiful his home was. He was born and raised in a picturesque village in northwestern Slovenia (formerly Yugoslavia), located in the European Alps. Surrounded by alpine and beech trees, Barbic dreamed of replicating their swaying in the wind for others to enjoy.
At the time, he didn’t have the tools or the knowledge to create a system that could do that, but it sparked his interest in computer graphics, he says.
Employer
University of Southern California, in Los Angeles
Title
Professor of computer science
Member grade
Senior member
Alma maters
University of Ljubljana, in Slovenia; Carnegie Mellon
Twenty years later, in 2016, Barbič, a professor of computer science at the University of Southern California, in Los Angeles, made his mark. His Ziva VFX software system allows for the creation of realistic muscle, fat, and skin simulations for 3D digital humans and creatures.
The technology was launched in 2016 by a startup he helped found, Ziva Dynamics, headquartered in Vancouver. It was acquired in 2021 by Unity Technologies of San Francisco.
Ziva VFX has been used in more than 60 movies including Aquaman and the Lost Kingdom; Godzilla x Kong: The New Empire; and Venom: Let There Be Carnage.
For the design and development of Ziva VFX, Barbič, an IEEE senior member, received a 2025 technical achievement Academy Award. It was a “tremendous honor,” he says, as the award recognizes technologies that have had a significant impact on motion picture production.
“Computer graphics and simulation can sometimes feel like a specialized technical field,” he says, “but the award showed that these ideas affect not just science but also art and how stories are told on screen.
“The digital characters enabled by mathematics become important parts of people’s lives.”
Barbič says he was inspired to pursue engineering by his father, an engineer who headed a cement factory’s research department and invented a technology that uses magnetic resonance imaging to test the integrity of cement. His father’s work showed him that “mathematics and physics are beautiful on their own, but engineering lets you build something that other people can use,” he says.
It was Barbič’s mother, an elementary school teacher, who introduced him to computer science. When he was 8 years old, the school his mother taught at bought a ZX Spectrum computer. With permission from the principal, she brought it home for her son to play on for two weeks. But he didn’t just play games; he created his own game using the BASIC programming language.
The machine came with a booklet that contained instructions on how to write a computer program, he says.
“At first,” he says, “I copied them verbatim without understanding what they did. But then I started realizing there is structure, and I modified the instructions.”
Of all the creatures brought to life using his technology, Barbič is particularly enamored with King Kong from 2024’s Godzilla vs. Kong.DNEG/Warner Bros. Entertainment Inc./Legendary
By the end of the two weeks, he’d developed a computer game where players guided a snowman along a winding road. It shifted unpredictably to the left or right, and players accumulated points by remaining on the road for as long as possible.
Barbič went on to earn a bachelor’s degree in mathematics in 2000 from the University of Ljubljana, in Slovenia. The following year, he moved to the United States to begin a doctoral program in computer science at Carnegie Mellon. It was a major turning point in his life, he says.
His doctoral research focused on developing simulation methods for objects that can change their shape when an outside force is applied to them, known as “deformable objects.”
That project shaped much of his later research, he says: “I became interested not only in making simulations accurate but also in making them practical: fast enough, robust enough, and controllable enough to be used in real applications.”
After earning his Ph.D. in computer science in 2007, he worked as a postdoctoral researcher at MIT. Two years later, he joined USC as an assistant professor.
It was at USC that Barbič merged his passion for computer science with film. He developed Vega FEM, an open-source software program that allowed people to animate realistic 3D deformable objects. But Vega FEM was narrow in scope and not exactly what filmmakers needed, he says, so he started exploring how to create a version suitable for the movie industry.
“A major theme of my career has been the translation of research ideas into practical tools,” he says. “Academic research often produces beautiful algorithms, but it can be difficult to make those algorithms usable by artists, engineers, or production teams. I have always been interested in that bridge: taking rigorous computational methods and turning them into systems that people can actually use.”
In 2011 he attended an Association for Computing Machinery conference presented by its Special Interest Group on Computer Graphics and Interactive Techniques (SIGGraph). There he met James Jacobs, the creature supervisor at visual effects company Weta FX of Wellington, New Zealand. The company is behind the effects in the Lord of the Rings and Hobbit trilogies and other movies. Jacobs used Barbič’s software to create animals and fantastical creatures.
Two years later, Weta FX offered Barbič a summerlong research position in New Zealand. He accepted and spent the time studying the process of creating visual effects and learning what roadblocks existed in the film industry, he says.
At the time, the technology to create realistic soft-tissue and anatomical simulation for digital characters didn’t exist.
“The visual effects industry had reached a point where surface-level realism was not enough,” Barbič says. “A creature could have beautiful skin textures and detailed geometry, but if the bones, muscles, and fat underneath did not move correctly, the illusion would break.
“The problem was especially difficult for creatures and characters that need to feel alive: animals, monsters, fantasy creatures, or digital doubles. Their bodies may have unfamiliar anatomy, but the audience still anticipates them to move in a way that matches real-world expectations. Muscles should bulge and contract, skin should stretch and slide, fat should have inertia, and tissue should respond to motion and impact.”
In an effort to solve the problem Jacobs in 2014 approached Barbič about founding a startup. In 2015 they launched Ziva Dynamics, where they began what is now Ziva VFX.
The software uses physics-based simulations to model the internal anatomy of a character. It numerically solves the partial differential equations of nonlinear elasticity for musculoskeletal human and creature tissues, Barbič says. The equations describe how muscles, fat, skin, and connective tissue deform, interact with bones, and connect, and how muscles activate. Instead of animating only the outside surface, artists can create a model with underlying muscles, bones, soft tissue, and fat. Each component is assigned material properties, constraints, attachments, and activations. The simulator then computes how they deform and interact over time.
The technology uses ideas from computational mechanics, finite element methods, numerical optimization, contact handling, and computer graphics, Barbič says. Finite element simulation, a method used to predict how a product or structure reacts to heat and other real-world forces, provides a way to model deformable materials volumetrically, not just as surfaces, he says. The tool computes internal elastic forces and solves the equations of motion so the character’s tissues respond plausibly to animation, pose changes, muscle activation, and dynamic motion.
But the system had to be designed for artists, Barbič says. In production, he says, the goal is not only physical realism but also controllable realism.
“Artists need to direct the result, iterate, and fit the simulation into a larger animation pipeline,” he says. “So the technology had to combine scientific simulation with practical controls, robustness, and integration with visual effects workflows.”
Barbič says Ziva VFX has been used in more than 60 movies. Of all the creatures brought to life using his technology, he is particularly enamored with King Kong from 2024’s Godzilla vs. Kong.
“When King Kong is walking, you can see the muscles, how they’re very pronounced, and how they influence the shape of the skin. You can really feel the strength of King Kong,” he says. “And this was made through my software, so I think it’s amazing.”
After Ziva Dynamics was acquired by Unity, Barbič consulted for the company for almost two years.
In 2024 DNEG, a London-based visual effects and computer animation company, acquired the exclusive license to Ziva VFX.
Barbič strives to improve visual effects as an entrepreneur and an academic. His most recent research, funded by the U.S. National Science Foundation, focused on the modeling, simulation, and animation of human hands. The goal is to create computer models of hands that can be used to design tools, medical prosthetics, and robotic hands.
“The hand is a fascinating and difficult system,” Barbič says. “It contains many small bones, muscles, tendons, ligaments, skin, fat, and other soft tissues, all packed into a compact structure and interacting mechanically in complex ways.”
He and his team built a digital twin of the human hand.
He aimed to move toward “anatomically meaningful simulation,” he says. He used medical imaging, geometric modeling, finite element methods, and multibody simulation to represent the internal structures of the hand and its motions.
“IEEE lets me place my work not only in the world of images and animation but also in the world of engineering systems that must be accurate, stable, interactive, and useful.”
He worked with Bohan Wang, who at the time was a USC doctoral candidate, and George Matcuk, an associate professor of radiology. Wang is now an assistant professor of computer science at the National University of Singapore.
Barbič, Wang, and Matcuk scanned four people’s hands with an MRI machine. The two men and two women would position their hands in 12 poses, which allowed the team to gather data about how the bones, muscles, and fat move with each pose.
The data sets are available for anyone to use in their own studies.
“This project can help medical doctors learn more about how the hand is moving,” Barbič says. “It’s also great for roboticists to better understand how the human hand actually works, so [the movements] can be replicated.”
Barbič joined IEEE in 2008, when he published his research paper on simulation methods for deformable objects in the inaugural issue of the IEEE Transactions on Haptics. He has since published several papers in the IEEE Transactions on Visualization and Computer Graphics, which he says connected his work to a wider community interested in visual computing and computational methods. You can find his research in the IEEE Xplore Digital Library.
“IEEE recognizes the engineering side of computer science,” he says. “My work is often presented as computer graphics, but at its core, it is also simulation, mechanics, numerical methods, haptics, visualization, and software systems.
“IEEE is a community where that broader identity makes sense. It lets me place my work not only in the world of images and animation but also in the world of engineering systems that must be accurate, stable, interactive, and useful.”
He believes the organization is key in supporting a healthy interdisciplinary research ecosystem at a global scale—which, he says, is why he has served as an associate editor for Transactions on Visualization and Computer Graphics and Transactions on Haptics.
Being a member has made it easier for Barbič to connect with engineers in different fields, he says.
“My research often lives between categories: It is mathematical but also practical; visual but also mechanical; artistic but also engineering-driven,” he says. “IEEE is one of the professional communities where that mixture is understood.”
2026-08-27 22:46:56
I never intended to join the cutting edge of electromechanical television. I just wanted to make a nice clock. But sometimes you have to go where the engineering takes you, and in my case it took me to the Scanwheel, a pocket-size wide-screen electromechanical TV with a resolution of 4,096 by 20 pixels. Yup, that’s 4K by 20.
The 3D-printed drum [top] is spun by a motor controlled by a driver board [second row, from top]. The driver board, in turn, is controlled by a Raspberry Pi Pico [middle], which also controls the LEDs [second row, from bottom], which are mounted in the 3D-printed casing [bottom] so that the holes pass over them as the drum turns.James Provost
Electromechanical television was the first form of practical television, developed by John Logie Baird in the 1920s. He used a so-called Nipkow disk, which has a spiral of holes punched through it. As the disk rotates, the holes pass one by one in front of a light source. By varying the brightness of the light as a hole travels across it, you can draw one scan line of a video frame. Spin the disk fast enough, and persistence of vision makes it look like an entire frame is being displayed simultaneously. Commercial electromechanical TV sets were produced in the United Kingdom, with regular broadcasts provided by the BBC in the 1930s.
Although cathode-ray tubes replaced electromechanical televisions in the 1940s, hobbyists have continued to build them and even improve on the original technology. For example, in the June 2022 installment of IEEE Spectrum’s Hands On, Markus Mierse presented a desktop-size 3D-printed color version.
I built an electromechanical display myself some years ago, but it had a traditional design with a Nipkow disk made from a vinyl record with holes drilled in it. Recently I started tinkering with electromechanical TV again as an outgrowth of my YouTube channel. There I’ve been focusing on developing volumetric displays, which create 3D pixels floating within a volume of space. In particular, I was interested in borrowing some ideas from plenoptic cameras, which use pinholes and lenses to capture multidimensional light fields of samples.
I wondered if I could run the process in reverse, to create light fields rather than capture them. I often explore ideas in two dimensions before expanding to the third, so I thought I’d first demonstrate a 2D display. I decided to make an electromechanical device into a clock. After all, you don’t need high resolution to display digits.
Thinking about the display as a clockface pushed me toward some key ideas. First, instead of having just one display area, I would use five light sources to create multiple areas—four to represent hours and minutes, and a central area for a separator that would blink each second. Second, to align the digits in a readable row rather than have them spread around an arc, I swapped the Nipkow disk for an established alternative: a Nipkow drum.
With a drum, the holes run along the curved cylindrical surface in a stair-step pattern. This means they always trace a straight line from the perspective of a viewer looking from the side, so the clock’s digits would be horizontally aligned.
“In tests, I’ve pushed the horizontal resolution to more than 8,000 pixels.”
These two decisions turned out to be key to achieving both miniaturization and high horizontal resolution. A disk needs a fairly wide diameter so that the scan lines aren’t ridiculously curved. But curvature isn’t a problem with a drum. A drum can be much smaller than a disk that has the same number of scan lines. (And unlike in the 1920s, packing multiple light sources close together inside a small drum isn’t a problem with modern LEDs.) I settled on a 6-centimeter-wide drum, turning the device from desktop-size to something you could carry in your pocket.
I then realized my five display zones could work in concert to create one single wide screen. Because it’s possible to modulate the brightness of an LED at very high rates, the horizontal resolution can also be very high. My system currently has 4K horizontal resolution, and this is primarily limited by the amount of onboard memory I have available. This memory holds the buffer that stores pixel data for each frame before it is read out to the LEDs and displayed. In tests, I’ve pushed the horizontal resolution to more than 8,000 pixels.
Despite the Scanwheel’s low vertical resolution—at 20 pixels, it has fewer scan lines than Baird’s 30-line televisions—its high horizontal resolution makes the legibility of the display surprisingly good: I can display not just crude digits but video streamed into the frame buffer.
That frame buffer lives on a Raspberry Pi Pico microcontroller board, based around the RP2040 microcontroller. The RP2040 is ideal for this project because of the chip’s dedicated PIO silicon. PIO stands for programmable input/output, and it’s a block of four coprocessors that uses a very limited instruction set. Each coprocessor can be set up to chew through input/output streams completely independently of the RP2040’s two CPU cores.
The first mechanical TVs used disks, which had to be wide to minimize image distortion but allowed bulky light sources. With small, modern light sources, a smaller drum can create images with minimal distortion.James Provost
It’s thanks to the PIO that I’m able to keep up with the spinning drum and modulate each of the five LEDs simultaneously as holes pass over them, a task complicated by the fact that the center LED is not a monochrome LED, but a color LED with separate red, green, and blue channels. In fact, the PIO does nearly all the work, pulling data from the frame buffer and controlling the LEDs and the spinning of the drum. The code running on the CPU (written in MicroPython) is primarily responsible for setting up the PIO and then leaving well enough alone.
A stepper motor connected to a driver board spins the drum, with power provided by the USB jack on the Pi Pico. All the Pi Pico has to do controlwise is send the board a pulse to incrementally advance the drum’s position once every millisecond. Video data is streamed into the Pi Pico via a network interface. You can set up the Scanwheel to mirror a portion of your computer’s screen, or to act as a separate display.
The casing, including the drum, is 3D printed. Now for a neat bit: In the Scanwheel’s GitHub repository at https://github.com/AncientJames/Scanwheel/tree/main, alongside all the other files you’ll need to make this project yourself, there’s an OpenSCAD file that generates the 3D-print file for the drum based on adjustable parameters. This means you can easily make a taller drum and add more scan lines, or try other customizations for your very own portable electromechanical display. You can even use it as a clock!
2026-08-27 04:00:04
The IEEE–Eta Kappa Nu (IEEE-HKN) honor society is preparing to host the Innovating the Future event on 6 November.
The inaugural one-day, in-person event is designed to provide a forum for IEEE and IEEE-HKN undergraduate and graduate student authors to present their original research papers. A keynote address and thematic presentation sessions are planned as well. Student attendees can network with their peers and gain firsthand experience with the academic publishing process.
To present at the conference, students had to submit an abstract of their research before 1 May. Students whose work was accepted were assigned a volunteer IEEE member to mentor them and guide them through the research writing process, including presenting and publishing their original work.
Those whose paper was accepted by 1 August were invited to present at the conference. The conference proceedings will be submitted for publication in the IEEE Xplore Digital Library.
IEEE Life Fellow Manuel Castro, the conference’s technical program chair, oversees IEEE-HKN’s Innovating the Future program committee. It manages the review process, organizes logistics, and handles the mentoring component.
“This new conference is important to IEEE, as well as to IEEE-HKN,” Castro says, “because it allows student authors to grow in their skills and competencies, and be supported while turning their technical activities into publications.”
“The conference offers me a chance to learn how to communicate my research to a broader audience, gain feedback from other student researchers beyond my institution, and see how my work can be made more accessible.” —David Kwabi-Addo
IEEE Life Fellow Sorel Reisman, a California State University professor emeritus and an IEEE-HKN governor-at-large, says that because the academic research landscape is rapidly shifting, the conference is timely.
“As AI increasingly threatens the integrity of research papers being published in leading journals and conference proceedings, it is essential that future scholars—many of them current IEEE-HKN students—grasp the established standards of legitimate, peer-reviewed research publishing,” Reisman says.
A cornerstone of the conference is its rigorous mentorship initiative, which pairs each author of an accepted abstract with an experienced IEEE volunteer. The mentors provide personalized guidance on organizing the students’ technical content into the correct format for publishing. They also discuss navigating the peer review process, structuring presentations, and preparing the final manuscript for publication.
The impact of the guided process can be valuable for both the mentors and their mentees. IEEE Member Wafa Elmannai, associate professor and chair of the electrical and computer engineering department at Manhattan University, in Riverdale, N.Y., and faculty advisor to the IEEE-HKN Gamma Alpha chapter, serves as a mentor.
“Research is essential to advancing technology and driving innovation,” Elmannai says.
She volunteered to be a mentor, she says, because she has seen how conducting research can transform a student’s future by building their confidence, curiosity, and critical thinking skills.
“Mentoring encourages students to step outside their comfort zones and develop innovative solutions that contribute to society,” she says.
For the students, the conference can be a critical stepping stone. David Kwabi-Addo, an IEEE graduate student member who is researching computational biology at MIT, is president of the IEEE-HKN Beta Theta chapter. He says he views the program as an opportunity to gain experience in producing academic scholarship.
“I submitted an abstract of my research paper because I see the conference as a chance to produce what could become my first conference publication,” Kwabi-Addo says. “The conference offers me a chance to learn how to communicate my research to a broader audience, gain feedback from other student researchers beyond my institution, and see how my work can be made more accessible.”
He says he hopes his participation will highlight the diverse breadth of research that future conferences can showcase.
Conference organizers are holding a series of workshops to guide students through every step of the academic publishing process. The workshops are open to anyone and available on the IEEE-HKN YouTube channel.
Topics previously covered are:
Registration is open to all for this upcoming workshop:
The Innovating the Future program is designed not only to improve the quality of submissions but also to foster long-term professional development and research communication skills to develop the next generation of IEEE authors. The conference is more than a venue for presenting research; it is a launchpad for innovators committed to advancing technology for humanity.
2026-08-26 20:00:01
The biggest threat to any crewed expedition to Mars is time. NASA’s shortest blueprint for sending people to the Red Planet and back requires spending 620 days in space and 30 days on Mars. Even setting aside the compounding challenges of building life-support systems that can operate without resupply for that long, or the fact that longer journeys leave more time for unlucky accidents, life in microgravity and solar and cosmic radiation will inexorably exact their cumulative toll on human bodies.
We want to make it possible to dramatically reduce the length of time crews must spend in space—down to just 335 days in transit or less. This will both simplify many engineering challenges and keep astronauts healthier and safer. We believe the key to this time reduction is a new approach to building a holy grail of space exploration, the bimodal nuclear rocket.
In the 1960s, U.S. open-air ground tests demonstrated much of the technology needed for nuclear thermal rockets as part of the NERVA and Rover projects.Nevada State Museum, Las Vegas
Technicians at NASA’s Lewis Research Center test a nozzle design for a nuclear thermal rocket in 1965. GRC/NASA
The prototype SNAP-10A, orbited in 1965, is to date still the only nuclear reactor launched into space by the United States. George Rinhart/Corbis/Getty Images
We are Kurt Polzin, chief engineer of NASA’s space nuclear propulsion project at the Marshall Space Flight Center, with over two decades of experience in advanced propulsion research, and Robert Schleicher, chief engineer for nuclear technologies and materials at General Atomics. And to explain just what a bimodal nuclear rocket is, and why the new version we have conceived together brings it closer to future reality, we first need to take a quick trip to the past.
As early as 1946, researchers realized that nuclear reactors had the potential to become extremely efficient thermal rocket engines. Most rockets are thermal rockets, and they work by expelling hot gases through a nozzle, thrusting the rocket forward. While there are other factors such as nozzle shape, generally speaking, the hotter and faster you make the rocket’s exhaust gases, the more acceleration the rocket will produce for a given mass of propellant. Because a smaller molecule will move faster than a larger one when heated to a given temperature, the smaller the molecular mass of your propellants, the better. By convention, the efficiency of a rocket engine is measured by how long the engine can exert a thrust equal to the initial weight of its propellant, a quantity known as specific impulse.
In a conventional thermal rocket, such as those used in every launch to orbit since Sputnik, the exhaust temperature and speed—and thus the specific impulse—is dictated by the energy released by a chemical reaction and the mass of the reaction’s by-product. The most efficient chemical rockets today combust hydrogen with oxygen, producing water and a specific impulse that tops out around 450 seconds.
But a nuclear rocket is not limited by chemistry. The heart of a nuclear thermal rocket is a nuclear fission reactor, in which chain reactions in uranium fuel release much more energy per kilogram than is possible with chemical combustion. A turbopump forces liquid hydrogen alone—with its very small molecular mass—through the reactor’s core, heating it to temperatures of at least 2,700 kelvin before expelling it, resulting in a specific impulse of 900 seconds or more.
In the 1950s and 1960s, the Rover and NERVA (Nuclear Engine for Rocket Vehicle Applications) programs ground-tested nuclear thermal rockets. By the early 1970s, the technology had matured to the point where flight tests were being planned. But changing political and budgetary winds led to nuclear thermal development being shut down in 1973.
Another prong of nuclear propulsion that has also demonstrated considerable promise is nuclear electric propulsion. In electric propulsion, instead of creating a stream of hot rocket exhaust through chemical reactions or exposure to the core of a nuclear reactor, electricity is generated and used to create electromagnetic fields that accelerate an ionized propellant such as xenon or lithium.
Various schemes to do this exist, including some that have already seen considerable time in space, such as the ion thrusters used on the Dawn asteroid mission launched in 2007. So far, these electric thrusters have only been powered by solar panels. But with a nuclear reactor as part of a power plant that supplies the juice, more thrust could be produced. And moving beyond solar power is particularly important in missions to the outer solar system where sparse solar photons would require enormous solar arrays.
With electric thrusters, specific impulses in the range of 2,200 to 4,600 seconds are possible, but currently with very low thrust. With the energy available to a nuclear-powered electric propulsion engine, you could have greater acceleration and reduced mission times. The nuclear reactor could also provide electrical power for all the spacecraft systems as well.
The System for Nuclear Auxiliary Power (SNAP) program launched the SNAP-10A in 1965 as a proof of concept, the first—and so far only—U.S. nuclear power reactor in space. It generated about 600 watts of electrical power for 43 days before shutdown and is still in orbit. Subsequent U.S. initiatives for more substantive electric power and nuclear thermal propulsion systems, such as the SP-100, Project Timberwind, and Project Prometheus, along with more recent projects like Demonstration Rocket for Agile Cislunar Operations (DRACO) and Joint Emergent Technology Supplying On-Orbit Nuclear (JETSON), have emerged sporadically over the years. None of these have yet progressed to actual flight.
However, space nuclear power got a huge shot in the arm in March 2026 when NASA Administrator Jared Isaacman announced a new space exploration initiative. As part of that initiative, the agency plans to launch Space Reactor-1 Freedom (SR-1) to deliver a trio of robot-survey helicopters to Mars. Driven by nuclear electric propulsion, SR-1 aims to demonstrate fission technology in deep space and would be the first nuclear-powered interplanetary spacecraft, generating 20 kilowatts of electric power aboard.
This is a bold step for NASA, and brings us up to the present, but the details of the proposed mission also highlight a familiar limitation of nuclear electric propulsion. Even with improved acceleration, electric propulsion still cannot generate the powerful bursts of thrust needed to escape gravity wells, such as those of Earth or Mars, or perform time-critical maneuvers, like course corrections. On the other hand, while not as efficient and unable to supply electrical power for spacecraft systems, nuclear thermal engines are great at delivering high thrust at critical moments.
Some engineers would suggest we build two separate systems—one reactor for thermal propulsion and another reactor for power and electric propulsion. But since at least the 1990s, it has been the dream of many engineers to combine nuclear thermal and nuclear electric in one package, with one reactor: the bimodal nuclear rocket.
Most previous bimodal proposals depend on complex valve arrangements to integrate the propulsion and power systems. In thermal propulsion mode, the reactor is brought to maximum activity by a set of control drums that ring the core, which is composed of a matrix of long uranium-fuel elements. The drums take the shape of long cylinders made of beryllium, with a 120-degree segment of each cylinder covered with boron carbide. Boron absorbs neutrons, and when that segment faces the reactor, the reactor’s activity is low as neutrons escaping from the core are captured. Rotating the boron segment so that it faces away from the core (leaving only the beryllium exposed) increases nuclear activity as the beryllium reflects escaping neutrons back into the core’s fuel elements, where they can contribute to chain reactions.
This proposed trajectory, developed at NASA’s Glenn Research Center, shows where high-thrust maneuvers [blue dots] are executed by a nuclear thermal engine and additional low-thrust, high-efficiency acceleration and deceleration is performed by electric propulsion [hashed lines show thrust direction].NASA Glenn Research Center
Once the reactor is generating large amounts of heat, liquid hydrogen is pumped through channels that run the length of the core. Turned into an expanding hot gas, the hydrogen blasts from the other end of the core to form the rocket’s powerful exhaust.
In nuclear power mode, the reactor’s activity is damped. Valves seal the channels and a so-called power-conversion fluid—typically a mixture of helium and xenon gas—circulates through the reactor in a closed loop. The reactor is still hot enough to warm this fluid, which drives a turbine connected to an electrical generator.
The key point here is that a single set of flow channels and nuclear-fuel elements are used for both modes. But the valves used to switch modes face the formidable challenge of enduring months, or even years, in a harsh radiation environment while maintaining leak-tight performance.
The core’s activity is controlled by the rotating drums surrounding it. Within the core, low-temperature fuel elements [left in blue, and top right] produce electric power by heating a circulating fluid. High-temperature fuel elements [left in red, and bottom right] heat hydrogen as a propellant. (The taper of the HTFE’s exhaust channel is exaggerated for illustrative purposes. Ways of packaging the HTFE’s uranium fuel other than with particles are possible.)John MacNeill
In addition, the nuclear-fuel elements surrounding the channels must be able to operate for short durations at very high temperatures during thermal thrust maneuvers and for long durations at lower temperatures during the rest of the voyage. It is difficult to build one type of element capable of both. Hence, the complexity and demanding engineering requirements of previous bimodal designs has hindered their practical application.
We propose a simplified approach, a hybrid system we call the synchronal bimodal nuclear rocket (S-BNR). The genesis for this design came about when we were attending a conference together in 2025. One of us (Polzin) had an initial idea, and in time-honored tradition, he sketched it out on a napkin to see if the other (Schleicher) thought there was actually a way to do it. We’ve been working on refining the concept ever since.
Rather than relying on a complex valve system, the S-BNR uses two hydraulically independent loops within a single reactor core, one open loop (for thermal propulsion) and one closed loop (for electrical power). The core is divided into two zones, one per loop, differentiated by the type of fuel elements in each. Several designs for the fuel elements are possible: In our preliminary design, the high-temperature fuel elements (HTFEs) in the thermal propulsion zone consist of a bed of “pebbles”—uranium fuel encased in zirconium carbide—that surround a central tapering channel and operate at greater than 2,700 K. (One possible alternative for the HTFEs would be a solid fuel design, as with NERVA.) The hydrogen propellant passes through the pebble bed, where the pebbles’ large surface area maximizes the transfer of heat needed for efficient high-thrust propulsion.
The other zone has low-temperature fuel elements (LTFEs), optimized for long-term, efficient production of electricity, which can range from tens of kilowatts to several megawatts. In these elements, the uranium fuel in solid form surrounds a double-walled channel: The power-conversion fluid is pumped down the inside and returns along the outside wall, absorbing heat from the fuel and operating at moderate temperatures (at or above 1,200 K).
The electric-power and nuclear-thrust elements of the core have separate fluid loops, which eliminates the need for valves to switch between closed-loop operation for power generation and open-loop operation for propulsion.John MacNeill
Both the HTFEs and LTFEs contribute the neutrons required to sustain chain reactions. In power-only mode, residual heat moves from the HTFEs into adjoining LTFEs. The physical interface between the elements is designed to moderate this thermal flow to balance two competing needs: It must allow enough heat flow to safely remove the residual heat from the HTFEs, but it must also limit that heat flow so the LTFEs’ temperatures do not go past their allowable limits when the HTFEs operate at high power.
During combined propulsion and power operation, a heat exchanger on the power loop preheats the hydrogen propellant for the thrust loop, aiding the turbopump that feeds the hydrogen through the core. After a propulsion burn is completed and the HTFE chain reactions are damped by the control elements, the power loop removes residual-decay heat coming from the HTFEs as described above, eliminating the requirement in earlier designs for additional propellant flow just to cool down the core while on standby. This dual-loop system also means the engine can produce high thrust whenever needed while allowing the generator to remain active at all times—a significant advantage for crewed missions.
By adopting this dual-loop architecture, the S-BNR removes the need for the problematic mode-switching valves found in earlier concepts. Each fission zone is constructed with materials tailored to its specific temperature and power requirements, ensuring optimal performance and durability. The result is uninterrupted electrical power across all mission stages, making it unnecessary to carry additional liquid hydrogen just to manage decay heat.
While significant progress in developing the design of the S-BNR has been made, substantial challenges remain. The reactor must maintain stable control across a wide power range, from modest levels for electricity generation to hundreds of megawatts of thermal power during high-thrust operation. Operating the power-generation loop in close proximity to the HTFEs requires very careful management of both temperature and the neutrons emitted by the fuel elements.
And crucially, demonstrating reliable, long-duration performance is particularly demanding: Missions to Mars may require years of continuous power generation. Outer-planet probes equipped with S-BNR engines could extend that to a decade or longer.
In the past, nuclear thermal propulsion fuel elements were engineered for extremely high temperatures but only brief operational lifetimes (typically hours), whereas proposed nuclear electric propulsion fuel elements are optimized for lower temperatures and intended to last for years. By using two different types of fuel elements in the S-BNR, we can take advantage of the design heritage of both these development tracks. Fortunately, recent NASA-sponsored research has produced several promising candidates that may meet these demanding requirements.
Ground-testing these systems is also a challenge. Early in the Rover and NERVA era, the exhaust from test engines was blasted into the atmosphere, something now unacceptable. Today, any ground test of an engine must completely capture all potentially radioactive exhaust products. Fortunately, a number of approaches have been developed to capture and scrub the exhaust, although these methods currently carry a significant price tag.
Then there is the ultimate test: flying an S-BNR in space. International regulatory and safety protocols for nuclear launches were developed largely in response to the Soviet Union’s launch of dozens of nuclear-powered Radar Ocean Reconnaissance Satellite (RORSAT) radar spy satellites in the 1970s and 1980s. There were a number of incidents, with the most serious leaving radioactive debris strewn across a swath of Canada in 1978. This history led to a consensus in the space community that might be summarized as “Thou shalt not bring a nuclear reactor to criticality in any Earth orbit that decays faster than dangerous isotopes.”
Thus any S-BNR would be launched atop a conventional chemical rocket, with a completely cold reactor and fresh fuel. Fresh uranium fuel is not in fact very radioactive: The potentially larger concern is the chemical toxicity of this heavy metal, but it can easily be handled by wearing light protective suits, respirators, and gloves. Only after the control elements have been adjusted to permit chain reactions to begin within the core are highly radioactive isotopes able to form from fission fragments. There would be even less cause for concern than when launching a radioisotope thermoelectric generator (RTG), such as the sort that are currently powering the Perseverance rover on Mars and the New Horizons mission in the outer solar system.
Even in the most extreme scenario imaginable—the chemical booster explodes and somehow damages the reactor’s control elements in just the right way to initiate a chain reaction—there wouldn’t be time to produce a large amount of toxic isotopes before the reactor broke apart and reactions ceased. (We can be sure of this because Project Rover actually tested this kind of worst-case scenario in 1965 with the Kiwi-TNT test, where an engine prototype was rigged to produce a runaway chain reaction sufficient to vaporize the reactor core due to the immense internal pressure buildup. Negligible radiation spread outside a radius of two miles (3.2 kilometers), well within the range of safe distances for launching any rocket capable of reaching orbit, and site decontamination was possible after only a few days of radioactive decay.)
Despite all these considerable engineering challenges, the foundation laid by decades of investment in nuclear thermal and electric propulsion and terrestrial nuclear power technologies provides a solid platform for continued advancement. Indeed, much of the foundational work is already underway through ongoing NASA and U.S. Space Force efforts.
The Dawn asteroid mission relied on electric thrusters, demonstrating their utility for long-duration spaceflight.JPL-Caltech/NASA
We envision the following action plan to merge these technology pathways: Modeling must be performed to demonstrate and verify strategies for thermal management and the control of nuclear processes over the full range of operating power levels. Near-term non-nuclear testing will validate fluid loop operation, heat transfer mechanisms, and control strategies. Next, component-level irradiation and thermal trials will qualify new materials. Then, integrated reactor testing will begin, first without nuclear fuel and later with fueled reactors undergoing fission. Finally, initial in-space demonstrations could begin with lower-power systems, eventually scaling up to full bimodal capabilities.
Achieving success will require close collaboration across NASA, the Department of Energy, the Department of Defense, industry partners, and the broader technical community. Progress will depend on advancements in high-temperature fuels and materials, improved systems for power conversion and heat transport, and the adoption of innovative manufacturing techniques and methods to control nuclear fission over a wide range of output power. In particular, integrated system testing will be more complex than previous programs such as NERVA, due to the combined functions and distinct operational regimes for thermal propulsion and power generation. We hope engineers and researchers with relevant expertise will be encouraged to contribute to addressing these challenges, whether in the areas of thermal management, reactor modeling and control, extended-duration testing, or safety analysis.
Past ground tests and limited demonstrations have already established the capabilities of space nuclear systems. With architectures like the synchronal bimodal nuclear rocket, the prospect of integrating high-thrust propulsion and sustained power generation becomes increasingly practical and versatile. The next phase is not simply about traveling fast. It’s about building crewed and uncrewed spacecraft that can reliably travel to destinations throughout the solar system that are currently difficult or impossible to reach, with missions potentially lasting years or even decades.
This article appears in the September 2026 print issue as “A Reimagined Nuclear Rocket.”