ZBLAN: The Hype Versus the Reality

Key Takeaways

• ZBLAN fiber can theoretically transmit signals 10–100x more efficiently than silica fiber
• Flawless Photonics produced nearly 12 km of ZBLAN on the ISS in early 2024, a major milestone
• Commercial viability remains unproven, hinging on economics, ISS access, and quality verification

Introduction

The story of ZBLAN is, in a sense, the story of a material that has been on the verge of changing the world for fifty years and hasn’t quite gotten there yet. That’s not a dismissal. The science is real, the experiments have produced genuine results, and the interest from governments, defense agencies, and telecommunications companies is not manufactured enthusiasm. But there’s a substantial distance between a remarkable experiment aboard the International Space Station and a supply chain capable of replacing the fiber optic cables running along the floors of every ocean on Earth. That distance is where the hype and the reality diverge most sharply.

Understanding what ZBLAN actually is, why it requires microgravity to reach its potential, what’s been accomplished so far, and what has yet to be proven takes some work. The technical terrain is genuinely interesting, and sorting through the bold claims requires following the thread from a laboratory accident in France in 1974 all the way to the ISS orbiting 400 kilometers above Earth today.

What ZBLAN Actually Is

The name itself is an acronym, and a somewhat ungainly one. ZBLAN stands for zirconium, barium, lanthanum, aluminum, and sodium fluorides, each combined in specific proportions to form a heavy metal fluoride glass. The material was discovered by accident in 1974 by Marcel Poulain and his brother Michel Poulain at the University of Rennes in France. They weren’t trying to find a revolutionary optical material. The discovery emerged from routine experimentation, which is how a surprising number of important materials science breakthroughs actually happen.

Four years after that discovery, the brothers co-founded Le Verre Fluoré, a company still operating today that manufactures specialty fluoride glass products including ZBLAN-based fibers. Their work placed them at the forefront of a niche but genuinely promising field, though commercial applications remained limited for decades because of a problem that turns out to be fundamental: Earth’s gravity.

Silica, the glass used in conventional fiber optic cables, is a relatively simple compound. It consists of silicon dioxide, and manufacturing it into fiber involves well-understood, highly optimized industrial processes. The global fiber optic cable industry has spent decades refining production, achieving remarkably consistent quality at scale. ZBLAN, by contrast, contains five different elements with meaningfully different densities and crystallization temperatures. During the manufacturing process, when the molten glass cools and solidifies, the heavier elements, particularly zirconium, barium, and lanthanum, tend to sink while lighter elements rise. This density-driven separation causes microcrystals to form throughout the fiber as it solidifies.

Those microcrystals aren’t just aesthetically undesirable. They scatter light, reduce transparency, and make the fiber mechanically brittle. A ZBLAN fiber produced under normal gravity conditions is, for many of the most promising applications, essentially unusable. The defects undermine the very properties that make the material exciting in the first place.

What makes the material exciting is the transmission window. Silica fiber transmits light efficiently in a relatively narrow wavelength range, roughly 1.3 to 1.6 micrometers in the near-infrared. ZBLAN has a far wider transmission window, extending deep into the mid-infrared spectrum around 4 to 5 micrometers. That broader range allows more wavelengths to carry data simultaneously, which translates directly into higher information-carrying capacity. At its theoretical best, ZBLAN fiber can have 10 to 100 times lower signal attenuation than silica fiber.

The implication for telecommunications is staggering, at least on paper. A 2,000-kilometer length of ZBLAN fiber could have the same optical loss as 10 kilometers of silica fiber. Repeaters in submarine communications cables, which currently boost weakening signals every 40 to 50 kilometers and consume roughly 1 to 1.5 percent of global energy expenditure, could potentially be spaced hundreds or even thousands of kilometers apart. For a material that most people have never heard of, the upside is genuinely large. The question is whether it can ever be manufactured at quality and volume levels sufficient to realize it.

Why Microgravity Changes Everything

The core insight driving the in-space manufacturing push is deceptively simple: if gravity causes the crystallization problem, removing gravity should largely eliminate it. In microgravity, the density-driven separation processes that produce microcrystals are suppressed. Convection, sedimentation, and buoyancy, the mechanisms that cause heavier elements to segregate from lighter ones during solidification, are essentially nullified. The fiber can cool and solidify while its five constituent elements remain uniformly distributed throughout the material.

A useful analogy, though imperfect ones always are, involves melting ice cream with mixed-in toppings. On Earth, when the ice cream melts, the heavier inclusions sink and lighter ones float. In microgravity, that separation doesn’t happen. The mixture stays homogeneous. For ZBLAN, that homogeneity during solidification is the entire point.

Researchers at NASA had inklings of this possibility as far back as the early experiments of the Apollo era, but it wasn’t until the 1990s that the U.S. Air Force and Naval Research Laboratory began investigating microgravity processing of ZBLAN in any systematic way. Parabolic arc flights aboard NASA’s KC-135 aircraft provided 22-second windows of near-weightlessness during each freefall maneuver. Those windows weren’t enough to pull proper fiber, but they produced encouraging preliminary results. The crystallization rate visibly decreased. That was enough to keep the idea alive.

The next step required a sustained microgravity environment. The ISS, operational from 2000, provided exactly that, and by the mid-2010s, commercial companies were beginning to eye it as a potential manufacturing platform.

There is a second, related challenge that often gets less attention: purity. Professor Heike Ebendorff-Heidepriem, deputy director of the University of Adelaide’s Institute for Photonics and Advanced Sensing, has noted that to fulfill its maximum potential, the glass purity must be enhanced by a factor of 1,000 over currently available terrestrial grades. Manufacturing high-purity ZBLAN preforms, the glass rods from which fiber is drawn, is itself a specialized and difficult process. The University of Adelaide’s facility is one of only a handful of places globally equipped to produce them. This purity challenge is distinct from the crystallization problem and doesn’t automatically get solved by going to space. Both issues need to be addressed simultaneously for space-made ZBLAN to truly deliver on its promise.

The Companies That Made the Bet

The modern era of ZBLAN in-space manufacturing began in earnest in 2016 when Made In Space, a California-based startup, announced a partnership with Thorlabs, a New Jersey photonics company, to produce ZBLAN fiber aboard the ISS. Made In Space had already demonstrated 3D printing in microgravity aboard the station and was looking for its next commercial product.

Made In Space sent a microwave-oven-sized ZBLAN manufacturing machine to the ISS on SpaceX’s CRS-13 mission in December 2017, marking the first privately funded attempt to draw ZBLAN fiber in orbit. The results were promising enough to justify follow-on missions. Over the next few years, Made In Space sent its device to the station four separate times. The company never publicly disclosed exactly how much fiber it produced, which is itself somewhat telling, but it characterized results as encouraging. Later, Redwire, which acquired Made In Space in 2020, continued the work under NASA’s InSpace Production Applications (InSPA) program.

Two additional early competitors entered the field around the same time. FOMS Inc. (Fiber Optics Manufacturing in Space), a San Diego-based company led by chief scientist Dmitry Starodubov, launched its suitcase-sized manufacturing module to the station with Small Business Innovation Research funding from NASA. FOMS demonstrated its first strands of high-quality ZBLAN in orbit at an optical fibers conference in November 2019, with astronauts aboard the station installing the equipment in the U.S. Destiny Lab and FOMS controlling operations remotely from NASA’s Marshall Space Flight Center in Alabama.

Physical Optics Corporation, based in Torrance, California, and later operating as part of Mercury Systems, developed the Orbital Fiber Optic Production Module (ORFOM). Both FOMS and the ORFOM arrived at the ISS in July 2022 aboard SpaceX’s CRS-25 mission to conduct further production demonstrations.

Then came Flawless Photonics.

The Silicon Valley startup, with an engineering office in Luxembourg that works closely with the European Space Agency, took a different approach. Rather than iterating on the basic draw-and-spool method that predecessors had used, Flawless focused on solving the restart problem. When fiber is being pulled from a heated preform in microgravity, it inevitably breaks. Every time it breaks and the machine can’t restart the draw automatically, the mission is over. Previous machines lacked reliable restart capability, which is why earlier efforts produced fiber measured in meters rather than kilometers.

Flawless Photonics’ hardware, designed by what the company describes as 14 machine builders in Luxembourg including space engineers, robotics experts, and chemists, could restart the draw process after each break. The machine launched to the ISS aboard Northrop Grumman’s NG-20 mission on January 30, 2024.

The 2024 Breakthrough and What It Actually Proved

Between mid-February and mid-March 2024, the Flawless Photonics payload in the ISS Microgravity Science Glovebox produced results that genuinely surprised people who had been watching this field for years. Over roughly one month of operations, with NASA astronaut Loral O’Hara conducting on-orbit procedures, the system manufactured a total of more than 11.9 kilometers (approximately 7.4 miles) of ZBLAN optical fiber. Eight separate draws each produced more than 700 meters of fiber, and the single longest draw exceeded 1,141 meters. The previous record for ZBLAN drawn in space was approximately 25 meters.

For context on why the 700-meter threshold matters: standard commercial spools of terrestrial ZBLAN fiber are sold in lengths of 700 meters. By producing eight such lengths consistently, Flawless had demonstrated not just a one-off achievement but a repeatable process capable of generating commercially relevant quantities. NASA’s InSpace Production Applications program characterized it as the first time commercial lengths of fiber had been produced in space.

Lynn Harper, strategy lead for NASA ISS InSpace Production Applications, called Flawless Photonics’ accomplishment something in a class by itself, noting the company had successfully manufactured commercial lots of ZBLAN repeatedly. That’s a meaningful statement from NASA, an organization not generally known for overstatement.

The University of Adelaide’s team, which supplied 20 ultra-pure ZBLAN preform rods for the experiment, called the results a remarkable achievement. The fiber drawn from those rods was returned to Earth aboard a SpaceX Commercial Resupply Services mission in April 2024 for detailed characterization.

So what did the 2024 experiment actually prove? It proved that sustained, repeatable production of commercially relevant fiber lengths is possible in microgravity. It demonstrated that an automated restart mechanism can solve the fiber-break problem. It showed that the manufacturing process can be controlled remotely from the ground and run largely autonomously in orbit. These are not trivial accomplishments. Compared to where this field stood in 2022, when it had been characterized as turning out to be harder than expected, the 2024 results represented a genuine step change.

What the experiment did not prove is more complicated, and this is where skepticism deserves its due. Production length is not the same as production quality. The samples returned to Earth needed to be tested for actual optical performance, specifically attenuation (how much signal is lost per unit length), compared directly against equivalent-quality terrestrial fiber. Scientists at the University of Adelaide and other research institutions took on that characterization work, with results expected throughout 2024 and into 2025. As of early 2026, comprehensive published comparisons of space-made versus ground-made ZBLAN attenuation remain the field’s most anticipated data.

There’s also the question of what “commercial grade” actually means. A 2025 paper published in Acta Astronautica and covered in the journal ScienceDirect pointed out that producing fiber of impressive length alone doesn’t establish commercial viability. The criteria for commercial grade ZBLAN fiber include attenuation performance against rigorous benchmarks, mechanical strength and flexibility, batch-to-batch consistency, and economic feasibility. Achieving one of these doesn’t guarantee the others.

The Economic Math, Which Is Where Things Get Genuinely Hard

Even if space-manufactured ZBLAN consistently outperforms terrestrial fiber on every optical metric, the business case depends on economics that don’t yet fully close.

Starodubov of FOMS laid out the basic unit economics publicly several years ago: specialty optical fibers, including terrestrial ZBLAN, have historically been priced at $100 to $200 per meter. At those prices, a relatively small payload of high-quality fiber could theoretically generate enough revenue to cover launch, on-orbit operations, and return costs. SpaceX’s reductions in launch costs have improved this calculation significantly compared to what it would have been in the early 2000s, when the economics were entirely unfeasible.

But the math isn’t quite as clean as the headline numbers suggest. Launching payload to the ISS still costs thousands of dollars per kilogram. The preforms must be manufactured to extreme purity specifications on Earth, shipped to the launch site, integrated with the orbital manufacturing payload, and then the finished fiber must be returned on a separate mission. The total cost of producing a commercial batch includes the engineering overhead of maintaining and operating orbital equipment, which is formidable.

The specialty fiber market, moreover, is not infinite. ZBLAN in its current terrestrial form already serves medical endoscopy, high-power laser generation, scientific spectroscopy, and some defense applications. The addressable market for a premium-priced, space-manufactured version is a subset of an already specialized market. The grand vision, replacing silica fiber in transoceanic submarine cables, would require not just superior quality but manufacturing at a scale orders of magnitude beyond what any ISS-based experiment has demonstrated.

Michael Vestel, chief technology officer of Flawless Photonics and holder of a PhD in materials science from the University of California, Berkeley, has been candid about where the big economic prize actually lies. He describes replacing undersea cables as the moonshot, the ambition that would justify massive investment and infrastructure buildout. The energy savings alone from reducing the need for in-line optical repeaters, which collectively consume something in the range of 1 to 1.5 percent of global energy expenditure, would be substantial. But getting from 12 kilometers of fiber produced on the ISS to hundreds of thousands of kilometers suitable for transoceanic deployment is not a roadmap anyone has fully written yet.

The ISS itself presents a structural constraint. The station is scheduled for decommissioning around 2030, when it will be guided into a controlled reentry over the Pacific Ocean. Every experiment running on the ISS is operating under a countdown. While NASA has been working through its NextSTEP (Next Space Technologies for Exploration Partnerships) program to develop commercial successors, and while companies including Axiom Space are building commercial modules currently attached to the station with plans for free-flight operation post-2030, the transition from ISS to commercial stations introduces uncertainty about manufacturing continuity.

Flawless Photonics has been preparing for exactly this transition. In January 2026, the company was selected through the second cohort of the European Space Agency’s BSGN (Business in Space Growth Network) Advanced Materials and In-orbit Manufacturing Accelerator, following a competitive call that drew 18 applications from 10 ESA member states. The program is designed to support Flawless in scaling from its ISS success toward fully automated, scalable in-orbit production, potentially on commercial platforms beyond the ISS. The company has stated it’s working with unnamed orbital manufacturing partners and intends to have multiple manufacturing machines in orbit during 2025 and into 2026.

The Ground-Based Alternative That Refuses to Go Away

Here’s where the picture gets more complicated and, honestly, more interesting. Since the 2010s, a parallel line of research has been exploring whether improvements to terrestrial manufacturing might close enough of the performance gap to make space-based production economically unnecessary.

The theoretical approach involves extremely rapid cooling of the molten ZBLAN glass during the solidification phase, combined with strong external magnetic fields that can influence the alignment and separation of the constituent elements. If the cooling rate is fast enough, there’s simply not enough time for heavy elements to segregate and crystals to form. The analogy is quenching steel, where rapid cooling locks in desirable microstructures that would otherwise rearrange themselves.

Researchers have reported encouraging results with drop-tower experiments, where ZBLAN is drawn in a tall facility during a period of free-fall lasting a few seconds, and with high-speed cooling systems. The Factories in Space research database noted as recently as 2024 that the latest research is pointing toward Earth-based solutions using very rapid cooling and strong magnetic fields as a potentially competitive approach.

Whether those terrestrial methods can consistently produce fiber quality equivalent to sustained microgravity processing is genuinely uncertain, and this is the one point where the author has no confident position. The physics of crystallization during rapid cooling is well understood in principle, but the practical implementation at commercial scale involves machinery and process control challenges that are not obviously simpler than running a manufacturing module in orbit. Both paths are active research programs. The race between them hasn’t been settled, and it’s possible that competition between the two approaches will ultimately serve the market better than either alone.

Applications Beyond Telecommunications

The conversation around ZBLAN tends to gravitate toward the telecom moonshot, which makes sense given the scale of the opportunity. But the more immediately accessible markets are narrower and technically different from replacing submarine cables.

Medical applications represent one of the cleaner near-term markets. ZBLAN fibers’ wide transmission window into the mid-infrared makes them well-suited for medical laser delivery systems, where transmitting specific infrared wavelengths for tissue ablation and diagnostics requires fiber that silica simply can’t handle. Terrestrially manufactured ZBLAN already serves this market despite its defects. Space-made fiber with better optical properties and improved mechanical strength (terrestrial ZBLAN is notoriously brittle) would be a meaningful upgrade for equipment manufacturers.

Defense and national security applications have drawn explicit attention. When Rose Hernandez, director of InSpace Production Applications for the ISS National Laboratory, described Flawless Photonics’ 2024 results as likely to prompt investigations into new types of glass very important for defense and national security, that’s not marketing language. ZBLAN’s infrared transparency range overlaps with wavelengths used in night vision systems, infrared countermeasures, and certain sensor applications. High-quality, defect-free fiber in those wavelength ranges is a capability with clear defense value, and defense procurement tends to be less price-sensitive than commercial telecom.

High-power laser applications represent another market segment. ZBLAN fiber can carry high-intensity laser pulses at wavelengths that silica fiber can’t handle without damage. Industrial and scientific laser systems using mid-infrared wavelengths are a growing field, with applications in materials processing, atmospheric sensing, and medical devices. The ZBLAN fiber market in this segment already exists; the question is whether space-made fiber can offer performance improvements that justify a premium price in what are often sophisticated, technically demanding buyer environments.

Rare-earth-doped ZBLAN introduces yet another dimension. Adding small quantities of rare-earth elements like erbium or holmium to ZBLAN fiber creates optical amplifiers and fiber lasers with unusual properties. In normal gravity, rare-earth ions, being substantially heavier than most other atoms in the fiber, tend to cluster together during solidification. Those clusters reduce the gain efficiency of the resulting amplifier. In microgravity, the clustering is suppressed, allowing higher doping concentrations while maintaining optical quality. Starodubov of FOMS has specifically highlighted this effect as meaningful for high-power optical amplifiers.

The Companies That Tried and Stopped

The history of ZBLAN isn’t just a story of the companies currently active. It’s also a story of ventures that didn’t survive the long gap between theoretical promise and commercial reality.

Varda Space Industries, which attracted significant attention for its approach to pharmaceutical manufacturing in microgravity (and successfully returned a capsule containing ritonavir crystals grown in space in February 2024), was at one point considering ZBLAN production among its potential product lines. The 2024 in-space manufacturing industry survey found Varda listed under ZBLAN as “dormant, cancelled.” ACME Advanced Materials, which had announced first production of superior silicon carbide wafers in microgravity in 2014 and raised EUR 400,000 in 2015, went dormant; its primary founder appears to have left the organization in 2018, and its social media presence went quiet. Several other ventures have cycled in and out of the space without ever achieving a sustained commercial position.

This pattern matters. Each of these companies entered with genuine technical rationale, attracted at least some funding, conducted experiments, and then quietly disappeared. The reasons vary, but the common thread is the gap between demonstrating a physical effect in microgravity and building a business around it. The barrier isn’t scientific credibility. It’s the capital intensity of orbital operations combined with a market that doesn’t yet have a clear entry point for premium-priced, space-manufactured specialty fiber.

Flawless Photonics has now achieved something its predecessors hadn’t: demonstrated production at commercially relevant lengths, repeatedly, and with institutional backing from both NASA and the European Space Agency. Whether that’s enough to thread the business needle where others didn’t remains to be seen. The smart read is that the 2024 results changed the probability distribution, not the final outcome.

The ISS as a Manufacturing Platform: Constraints and Realities

The International Space Station has been the primary venue for every meaningful ZBLAN manufacturing experiment to date, and it was never designed for manufacturing. The U.S. Destiny laboratory module, where most ZBLAN experiments have been conducted, is 8.4 meters long and 4.2 meters wide, roughly the volume of a small apartment. Available power, thermal control capacity, and crew time are all shared resources competed for by dozens of active research programs at any given time.

The Microgravity Science Glovebox where Flawless Photonics’ equipment operated is a sealed, enclosed work area designed for scientific experiments. It’s not an industrial clean room. The production rates achievable on the ISS are constrained by the physical size of the equipment (manufacturing modules must fit in Dragon cargo capsules for launch and return), the available power budget, and the amount of crew time or autonomous operational capacity that can be dedicated to fiber production.

The ISS also experiences small but nonzero residual accelerations, referred to as quasi-steady accelerations and g-jitter, caused by crew activities, attitude control thruster firings, and structural vibrations. These micro-accelerations are generally small enough not to significantly compromise ZBLAN production, but they’re not zero. A dedicated in-space manufacturing facility on a future commercial station could, in principle, be designed for lower vibration and better isolation from crew-induced disturbances.

The commercial station ecosystem developing under NASA’s NextSTEP framework includes Axiom Space, which has had a module attached to the ISS since 2022 and plans to detach and operate independently after the ISS is decommissioned; Vast, which launched its Haven Demo pathfinder mission in 2025; and other ventures. None of these platforms have yet hosted ZBLAN manufacturing operations, but the transition to commercial stations represents both a risk and an opportunity for the field. Risk because the manufacturing continuity and institutional relationships built on the ISS don’t automatically transfer. Opportunity because commercial stations can theoretically be designed with manufacturing payloads as first-class customers rather than accommodated guests.

What Hasn’t Been Answered

The honest accounting of the field as of early 2026 acknowledges a number of fundamental questions that remain open.

Quality verification is the most pressing. The fiber produced by Flawless Photonics in early 2024 was returned to Earth and sent to the University of Adelaide’s Institute for Photonics and Advanced Sensing and other characterization partners. Optical attenuation testing, mechanical strength testing, and comparison against the best available terrestrial ZBLAN are the data points the field needs most urgently. The production achievement is real. Whether that production translates into fiber that is measurably, reproducibly superior to what can be made on Earth in properly controlled conditions is the question that will define what happens next. As of early 2026, comprehensive published results from that characterization have been anticipated but not yet widely available.

Preform manufacturing in space represents the next frontier in production. Currently, the glass preforms are made on Earth, transported to orbit, and drawn into fiber there. The purity requirements for those preforms are stringent, and terrestrial manufacturing of ultra-pure ZBLAN glass is itself technically demanding. Flawless Photonics, in partnership with the University of Adelaide, Axiom Space, and Visioneering Space, is working on NASA-funded experiments to demonstrate preform manufacturing in microgravity. If preforms can be made in space, the entire production chain could theoretically benefit from microgravity conditions at both stages, potentially enabling even higher purity and fewer defects.

Standardization of testing and quality metrics is another gap noted by independent researchers. The paper in Acta Astronautica from 2025 argued that without standardized, rigorously validated evaluation methods accepted by both the space manufacturing community and the terrestrial fiber optic industry, it’s difficult to make definitive claims about commercial-grade quality. A ZBLAN fiber produced in space that has excellent attenuation in some wavelength ranges but poorer performance in others may be commercially valuable for some applications and useless for others. Meaningful comparison requires agreed-upon benchmarks.

The launch cost trajectory matters enormously. SpaceX’s Falcon 9 and the prospect of Starship have reshaped the economics of reaching orbit, and continued reductions in launch costs improve the business case for in-space manufacturing in ways that are difficult to model precisely. A meaningful further reduction in the cost per kilogram to LEO could shift the economics of ZBLAN production from marginal to clearly viable.

The Current Players and Their Positions

As of early 2026, Flawless Photonics occupies the most advanced technical position in the field. Its silicon valley commercial headquarters focuses on market development and customer relationships while the Luxembourg office, funded in part by the Luxembourg Space Agency and the European Space Agency, leads hardware development. The company has been selected for ESA’s BSGN accelerator’s second cohort, announced in January 2026, specifically to support scaling toward autonomous in-orbit production. It is NASA’s most visible ZBLAN success story.

Redwire, which absorbed Made In Space and its years of ZBLAN experimentation, continues to operate across the broader in-space manufacturing space but has been less prominently associated with ZBLAN specifically in recent program updates. FOMS Inc. and Mercury Systems’ legacy ORFOM program remain technically active but have attracted less recent attention than Flawless Photonics’ breakthrough results.

The field is also not limited to American companies. Le Verre Fluoré in France, the company co-founded by ZBLAN’s original discoverers, continues to manufacture specialty fluoride glass products on the ground and is an important supplier of ZBLAN material. The University of Adelaide remains central to preform manufacturing and quality characterization. The involvement of the Luxembourg Space Agency and ESA in funding Flawless Photonics reflects European recognition that advanced materials manufacturing in space is a strategic priority.

The Defense Angle That Doesn’t Get Enough Attention

The potential defense and national security applications of high-quality ZBLAN fiber deserve more examination than they typically receive in coverage of this field.

ZBLAN’s mid-infrared transmission window overlaps with thermal emission signatures of military targets, which are detected and tracked using infrared sensor systems. High-quality, defect-free ZBLAN fiber can carry infrared signals at wavelengths where silica fiber becomes opaque. This has implications for fiber-coupled sensors, infrared countermeasure systems, directed energy weapon beam delivery, and secure communications systems operating in wavelength ranges that conventional fiber networks can’t handle.

The U.S. Air Force funded early ZBLAN microgravity research in the 1990s alongside NASA and the Naval Research Laboratory. The U.S. military understands the potential and has been part of the background funding landscape for this technology through the SBIR (Small Business Innovation Research) grant programs that supported both FOMS and Physical Optics Corporation. Rose Hernandez’s statement about Flawless Photonics’ results being important for defense and national security wasn’t incidental commentary. Defense procurement for specialty optical fiber, unlike commercial telecom fiber, can sustain premium prices and relatively low volumes while still creating a commercially viable production business. The path to first commercial sales might run through defense customers more quickly than through telecom ones.

Reading the Hype Correctly

The promotional language around ZBLAN in space has been extravagant at times and deserves honest examination. The claim that ZBLAN will replace silica fiber in transoceanic cables within the foreseeable future should be treated as a long-term aspiration, not a near-term business plan. Replacing existing submarine cable infrastructure, representing trillions of dollars of investment and maintained by specialized cable ships, is a multigenerational undertaking even if the technology performs exactly as hoped.

The claim that ZBLAN fiber can transmit signals 10 to 100 times more efficiently than silica is accurate as a theoretical statement about the material’s properties but somewhat misleading as a description of what space-made fiber can currently deliver. The 10 to 100 times figure represents the theoretical limit based on the glass’s optical properties. Achieving that limit requires not just eliminating crystallization defects but also achieving purity levels a thousand times higher than currently available, maintaining precise geometric uniformity throughout the fiber, and solving connector and integration challenges at either end. Terrestrial silica fiber manufacturing has benefited from fifty years of incremental improvement. ZBLAN is, by comparison, in its infancy.

The more modest and defensible version of the story, that space-manufactured ZBLAN fiber can achieve meaningfully lower attenuation than anything currently producible on Earth in the same wavelength ranges, and can do so in lengths long enough to be commercially useful, is what the 2024 Flawless Photonics experiment began to demonstrate. The magnitude of the improvement over the best terrestrially manufacturable fiber (as opposed to the theoretical limit) is what the 2024 characterization results are expected to quantify.

There’s a version of this technology that changes photonics, medicine, defense systems, and eventually telecommunications on a substantial scale, without ever replacing silica fiber in consumer broadband networks. That version is entirely plausible and commercially valuable. Overpromising the larger transformation risks obscuring the genuine near-term opportunity.

What the Future Actually Looks Like

The future market research numbers circulating for in-space manufacturing, including projections placing ZBLAN fiber optics at 14.8 percent of a market valued at $6.3 billion in 2025 and projected to reach $39.2 billion by 2035, should be approached with the same skepticism one applies to any growth market forecast that depends on multiple technologies working out as hoped. These numbers reflect optimistic scenario modeling rather than grounded revenue analysis.

The more grounded path forward for ZBLAN in-space manufacturing likely involves three phases. The first is quality verification, the confirmation through published independent characterization that space-made ZBLAN fiber has measurably superior optical properties to the best available terrestrial equivalents. If those results are as positive as the production milestone suggests they might be, they will constitute the technical foundation for commercial development.

The second phase involves identifying and winning early commercial customers, likely in defense, medical laser systems, and scientific instrumentation, where premium pricing is feasible and volume requirements are modest. Those initial commercial revenues would fund continued development while demonstrating that the supply chain from orbit to customer can operate reliably.

The third phase, the long game, involves demonstrating that the manufacturing process can be scaled on commercial space platforms after the ISS is decommissioned, producing fiber at volumes and costs that open progressively larger market segments including, eventually, the telecommunications applications that animate the moonshot vision.

Flawless Photonics’ involvement in the ESA BSGN accelerator for scaling toward autonomous in-orbit production suggests the company understands this arc and is preparing for the commercial station era. The fact that Axiom Space is a named partner in the preform manufacturing experiment also signals that the relationship between ZBLAN manufacturers and post-ISS commercial platforms is already being cultivated.

Whether the timeline unfolds over five years or twenty is genuinely impossible to predict. The history of ZBLAN, stretching from an accidental discovery in Rennes in 1974 through four decades of intermittent research and abortive commercialization attempts, suggests treating optimistic timelines with respectful skepticism. But the 2024 results from Flawless Photonics genuinely represent a different order of evidence than what came before, and the institutional support from NASA, ESA, and the Luxembourg Space Agency represents a more durable foundation than earlier commercial ventures had access to.

The hype around ZBLAN isn’t entirely wrong. The physics is real. The need is real. What’s been accomplished in orbit is genuinely impressive. What remains unresolved is whether the full chain, from space manufacturing to verified quality to commercial scale to affordable economics, can be completed before the window of ISS access closes, before terrestrial alternatives close the performance gap, and before the investment community loses patience with a fifty-year-old idea that has kept being almost ready.

Summary

ZBLAN is a heavy metal fluoride glass discovered accidentally in France in 1974 that can theoretically transmit optical signals 10 to 100 times more efficiently than the silica fiber that powers global communications. The problem is gravity. When manufactured on Earth, ZBLAN’s constituent elements separate by density during solidification, forming microcrystals that ruin the fiber’s optical performance. Manufacturing in the microgravity of low Earth orbit suppresses this crystallization, and after years of small-scale experiments on the ISS, Flawless Photonics produced nearly 12 kilometers of ZBLAN aboard the station in early 2024, the first time commercially relevant lengths had been demonstrated in space.

That achievement was real and meaningful. But production length is not the same as verified optical quality, and the complete characterization of space-made versus ground-made ZBLAN attenuation remains the field’s most consequential outstanding question as of early 2026. The economics of the full production chain, from high-purity preform manufacturing through launch, orbital production, return, and sale, have not yet been proven at scale. The ISS faces decommissioning around 2030, and while commercial station successors are in development, the transition introduces uncertainty. Competing research into rapid terrestrial cooling methods hasn’t been ruled out as an alternative path to similar quality.

The near-term market for space-manufactured ZBLAN most likely runs through defense applications, medical laser delivery systems, and scientific instrumentation rather than the grand vision of replacing transatlantic submarine cables. Those applications can sustain premium prices at modest volumes. The bigger telecom opportunity, while scientifically legitimate as a long-term goal, requires manufacturing infrastructure and cost structures that are still several steps beyond the current state of the art.

The story of ZBLAN is not hype or reality in clean opposition. It’s a material with genuine, quantifiable advantages, a manufacturing problem that microgravity can address, a series of experiments that have progressively proven more of the underlying physics, and a commercial case that has gotten meaningfully stronger since 2024 but hasn’t yet closed. That’s not a dismissal. It’s an accurate description of where a fifty-year-old breakthrough actually stands.

Appendix: Top 10 Questions Answered in This Article

What is ZBLAN and when was it discovered?

ZBLAN is a heavy metal fluoride glass composed of zirconium, barium, lanthanum, aluminum, and sodium fluorides. It was discovered accidentally in 1974 by brothers Marcel Poulain and Michel Poulain at the University of Rennes in France while conducting routine glass experiments.

Why can’t ZBLAN be manufactured effectively on Earth?

When ZBLAN is melted and drawn into fiber under Earth’s gravity, the five constituent elements, which have different densities, separate during solidification. Heavier elements like zirconium, barium, and lanthanum sink while lighter ones rise, and this phase separation causes microcrystals to form throughout the fiber, degrading its optical performance and making it mechanically brittle.

How much better is ZBLAN than silica fiber in theory?

At its theoretical best, ZBLAN fiber can have 10 to 100 times lower signal attenuation than conventional silica fiber. A 2,000-kilometer length of ZBLAN fiber could have the same optical loss as just 10 kilometers of silica fiber, which would allow optical repeaters in submarine cables to be spaced thousands of kilometers apart instead of 40 to 50 kilometers.

What did Flawless Photonics achieve in 2024?

Between mid-February and mid-March 2024, Flawless Photonics produced more than 11.9 kilometers of ZBLAN optical fiber aboard the ISS, with eight separate draws each exceeding 700 meters. This was the first time commercial-length quantities of ZBLAN had been produced in space, surpassing the previous record of approximately 25 meters by a factor of roughly 45.

Which companies have been developing ZBLAN in space?

The main companies active in this field have included Made In Space (later acquired by Redwire), FOMS Inc. of San Diego, Physical Optics Corporation of Torrance (California), and Flawless Photonics, a Silicon Valley startup with an engineering office in Luxembourg funded in part by the European Space Agency and the Luxembourg Space Agency.

What is the key commercial barrier to ZBLAN success?

The primary commercial barriers are the economics of the full production chain, including launch costs, preform manufacturing, orbital operations, and return logistics; the requirement that space-made fiber be demonstrably and measurably superior to terrestrial equivalents; and the limited production capacity of the ISS compared to what would be needed to address large-scale telecom markets.

What applications would benefit most from space-made ZBLAN fiber?

The most immediately accessible markets are medical laser delivery systems operating in the mid-infrared, defense and national security sensor systems, and scientific instrumentation. Long-term, the telecommunications industry, particularly submarine cable systems, represents the largest potential market but requires manufacturing at a scale not yet demonstrated in orbit.

Is there a way to manufacture high-quality ZBLAN on Earth without going to space?

Researchers have been investigating Earth-based approaches using very rapid cooling and strong magnetic fields to suppress crystallization during solidification. These methods have produced encouraging results and represent a competing path to improving terrestrial ZBLAN quality, though whether they can consistently match the performance achievable through sustained microgravity manufacturing is not yet established.

What happens to ZBLAN manufacturing when the ISS is decommissioned?

The ISS is scheduled for decommissioning around 2030. Companies like Flawless Photonics are preparing for this transition by working with commercial space station developers, including Axiom Space, and through programs like ESA’s BSGN accelerator, which selected Flawless in January 2026 to support scaling toward autonomous in-orbit production on post-ISS commercial platforms.

Has space-made ZBLAN been proven to outperform terrestrial fiber in optical tests?

As of early 2026, comprehensive published quality characterization comparing space-made ZBLAN from the 2024 Flawless Photonics mission against equivalent-quality terrestrial fiber has been anticipated but not yet fully released. Production capability at commercial lengths has been demonstrated, but independent verification of optical attenuation performance remains the critical next data point for the field.