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Imagine you’re at a dinner party and someone asks what you do. You explain you’re working on a revolutionary new battery technology. They lean in, eyes sparkling with interest. “So when can I buy one?” they ask. You pause. This is the moment where most technology conversations go sideways.
The gap between “we discovered something amazing in the lab” and “you can buy it at Target” is wider than the Grand Canyon. And understanding this gap is precisely what Technology Readiness Levels are designed to help us navigate. Not just for engineers, but for anyone who needs to understand where a technology actually stands in its journey from concept to reality.
What Even Are Technology Readiness Levels?
Think of Technology Readiness Levels, or TRLs, as a ladder with nine rungs. Each rung represents how far a technology has progressed from pure concept toward being something you can actually use in the real world. NASA invented this system in the 1970s because they kept running into the same problem: scientists would get excited about discoveries that were nowhere near ready to fly into space, and managers had no good way to figure out what “nowhere near ready” actually meant in concrete terms.
The beauty of TRLs is that they force everyone to speak the same language. When someone says they’re at TRL 3, you know exactly what that means. When they claim to be at TRL 8, you can ask specific questions about their testing environment. It’s like having a shared ruler when everyone used to be arguing about whether something was “kind of big” or “really big.”
Here’s the basic structure:
TRL 1 through 3 are the idea phase. You’re still working out basic principles, doing computer models, maybe running small experiments in controlled lab settings. Think of this as the “we think this might work” stage.
TRL 4 through 6 are the validation phase. You’re building prototypes, testing them in increasingly realistic conditions, demonstrating that your technology actually functions in environments that resemble where it will eventually be used. This is the “we’re pretty sure this works” stage.
TRL 7 through 9 are the deployment phase. You’ve built a full system, tested it in actual operating conditions, and proven it works reliably in the real world. This is the “this definitely works and you can use it” stage.
The Deceptive Geography of Innovation
Here’s something that surprises most people: moving up this ladder doesn’t happen at a steady pace. The early rungs might take months. The middle rungs can take years. The final rungs? Sometimes decades.
This isn’t because engineers are lazy or organizations are inefficient. It’s because each level reveals problems you couldn’t have anticipated at the previous level. It’s like climbing an actual mountain where you can’t see the next obstacle until you’ve conquered the current one.
Consider lithium batteries. The basic science of lithium ion technology was understood in the 1970s (TRL 1-3). Building working prototypes took another decade (TRL 4-6). But getting them reliable enough, safe enough, and cheap enough for commercial products? That took until the 1990s. And we’re still improving them today.
The counterintuitive truth is that proving something works in a lab is often the easy part. The hard part is proving it works when someone’s kid spills juice on it, when it’s used in a dusty warehouse in Phoenix, when it needs to function for ten years straight without maintenance, when it has to be manufactured by the millions at a price people will actually pay.
Why Most “Revolutionary” Technologies Aren’t Ready
Walk through any tech conference and you’ll see hundreds of companies claiming they have the next big thing. Solar panels with double the efficiency. Batteries that charge in seconds. Materials stronger than steel and lighter than aluminum. Most of them are stuck somewhere between TRL 3 and TRL 5, which means they’re years away from market, if they ever get there at all.
This isn’t cynicism. It’s understanding what those TRL numbers actually mean. A breakthrough at TRL 3 means someone proved the basic physics works. That’s genuinely exciting for scientists. But between TRL 3 and TRL 9 lies an ocean of engineering challenges, each one capable of sinking the entire project.
Can you manufacture it consistently? Can you scale production? Can you make it cheaply enough? Will it last as long as people need it to last? Can you make it safe enough to satisfy regulators? These questions multiply as you progress through the levels, and each one opens up new worlds of complexity.
This is why venture capitalists get nervous about anything below TRL 6. They’ve seen too many promising TRL 4 technologies that looked revolutionary in the lab but fell apart when exposed to real world conditions. The technology itself might work perfectly, but perhaps it requires platinum that costs more than most countries’ GDP, or it degrades after three months of normal use, or it only functions in climate controlled environments.
The Valley of Death
Between TRL 4 and TRL 7 lies what people in the innovation business call the Valley of Death. This is where most technologies go to die, not because they’re bad ideas, but because crossing this valley requires enormous resources.
At TRL 4, you’re still in academic territory. Universities run labs, publish papers, apply for research grants. The costs are manageable. The pressure is low. At TRL 7, you’re in commercial territory. Companies build factories, hire teams, invest millions. The potential returns justify the spending.
But TRL 5 and 6? You need serious money to build and test proper prototypes, but you’re still too early to attract major corporate investment. You’re too advanced for academic grants but too risky for business loans. You need specialized equipment and expert staff, but you can’t yet promise investors a clear path to profit.
This is why so many amazing lab discoveries never become products. Not because they don’t work. They just can’t find the resources to cross the valley. It’s like having a map to buried treasure but no money for a shovel.
Some countries have tried to bridge this gap with government programs specifically designed to fund TRL 5 and 6 development. The results have been mixed. Turns out that even with funding, many technologies hit fundamental barriers at these levels that simply can’t be overcome with the current state of knowledge or manufacturing capabilities.
How to Read TRL Claims
When someone tells you about their technology, asking about TRL can cut through mountains of marketing language. But you need to know how to interpret the answer.
First, understand that TRL assessments are somewhat subjective. There’s no TRL police checking whether companies are being honest. A startup desperate for funding might optimistically claim TRL 6 when they’re really at TRL 4. They’re not necessarily lying. They might genuinely believe they’re further along than they are.
Second, different parts of a technology can be at different TRLs. Maybe the core mechanism is at TRL 7, thoroughly tested and reliable. But the user interface is at TRL 4, still being refined. Or the manufacturing process is at TRL 5, proven in pilot runs but not yet scaled up. A technology is only as mature as its least mature critical component.
Third, context matters enormously. Something might be at TRL 8 for space applications, meaning it’s been thoroughly tested in the brutal environment of space and proven reliable. But if you want to use it in consumer electronics, you might need to redesign it entirely, potentially dropping back to TRL 4 or 5 for this new application.
The questions to ask are: “TRL according to whom?” “TRL for what specific application?” and “What’s your evidence for that assessment?”
The Hidden Complexity Behind Simple Products
Pick up your phone. That simple device represents hundreds of different technologies, each of which had to progress through all nine TRLs before they could be integrated. The touchscreen technology, the battery, the processor, the camera, the wireless radios, the software. Each one took years or decades to mature.
This is why predicting when new technologies will reach market is so difficult. Even if your core innovation is at TRL 8, you might depend on five other technologies that are only at TRL 5. You can’t launch until everything is ready.
Consider self driving cars. The sensors work (TRL 8 or 9). The computers are powerful enough (TRL 9). The basic algorithms function (TRL 7 or 8). But integrating all these pieces into a system that can handle every possible driving scenario? That’s still somewhere around TRL 6 or 7, even after billions of dollars of investment and over a decade of intensive development.
The challenge isn’t any single component. It’s the exponential complexity of making them all work together reliably under all conditions. Every time engineers solve one problem, they discover three more. This doesn’t mean self driving cars are impossible. It means the engineering challenge is vastly more complex than the initial prototypes suggested.
TRLs in Other Domains
While TRLs were invented for engineering, the concept has spread to other fields because the underlying pattern is universal. Medical treatments progress through similar stages, from laboratory research to animal testing to human trials to widespread clinical use. Social programs go from pilot projects to regional implementations to national rollouts.
The pharmaceutical industry has something remarkably similar. A drug that shows promise in a petri dish (equivalent to TRL 1-3) faces a brutal journey to pharmacy shelves (TRL 9). More than 90% of drugs that enter human trials fail. Not because they don’t work in principle, but because they don’t work well enough, safely enough, or reliably enough in the messy reality of human bodies.
Even software, which seems more fluid and less bound by physical constraints, follows this pattern. Code that works on a developer’s laptop (TRL 3) is very different from code that can handle millions of concurrent users across different devices and networks (TRL 9). Ask anyone who’s launched a major app about the nightmarish gap between “it works on my machine” and “it works for everyone, everywhere, all the time.”
The framework helps because it acknowledges a fundamental truth: early success does not predict later success. Just because something works in a controlled environment doesn’t mean it will work in the chaos of the real world.
What This Means for You
If you’re investing in technology companies, asking about TRL can save you from expensive mistakes. A company at TRL 4 might have great science, but they’re still years away from revenue. That’s fine if you understand what you’re buying into. It’s disastrous if you think you’re investing in something nearly ready for market.
If you’re working in innovation, TRLs give you a realistic framework for planning. They help you resist the temptation to over promise and under deliver. They let you communicate clearly with stakeholders about progress and challenges. They help you identify what resources you’ll need at each stage.
If you’re evaluating claims about new technology, whether in the news or in marketing materials, TRL thinking helps you ask the right questions. When someone announces a breakthrough, you can ask where it sits on the maturity scale. When someone promises a product launch date, you can evaluate whether they’re actually far enough along to meet that timeline.
Most importantly, understanding TRLs helps you appreciate why technological progress often feels slower than promised. It’s not that innovators are incompetent or dishonest. It’s that the journey from idea to product is genuinely difficult and filled with challenges that only become visible as you progress.
The Humility of Maturity
There’s something almost philosophical about TRLs. They embody a kind of institutional humility. They’re an admission that we can’t know everything upfront, that the path from concept to reality is treacherous, that early success doesn’t guarantee later success.
This stands in sharp contrast to the way we often talk about innovation, with its emphasis on disruption and revolution and breakthrough moments. TRLs remind us that most innovation is gradual, iterative, and much harder than it looks from the outside.
The framework also reveals something about human nature. We love the drama of discovery, the TRL 1 through 3 moments when someone has a flash of insight or proves a new principle. We get bored by the grinding work of TRL 5 through 8, the thousands of small improvements and solutions to unexpected problems that actually turn ideas into products.
But both are essential. Vision without execution is just daydreaming. Execution without vision is just busywork. The TRL framework honors both, giving each its place in the larger journey.
Looking Forward
As technology becomes more complex and more central to our lives, having shared frameworks for assessing maturity becomes increasingly important. TRLs aren’t perfect. They can be gamed, misapplied, or misunderstood. But they’re vastly better than having no framework at all, leaving everyone to guess what “almost ready” or “nearly there” actually means.
The next time someone tells you about an amazing new technology that’s going to change everything, you’ll know what questions to ask. Not to be cynical or dismissive, but to understand where they really are in the journey. Because the journey matters. The rungs on the ladder matter. And knowing where you stand on that ladder makes all the difference between informed optimism and wishful thinking.
Innovation is hard. That’s not a bug. It’s a feature. The difficulty is what makes genuine breakthroughs valuable. Understanding TRLs helps us appreciate both the challenge and the achievement, the distance traveled and the distance still to go.