Big Ideas Lab
Scientists at JASPER study one of the most consequential materials on Earth: plutonium.
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As the car door slams shut, dust scatters. Ninety miles one way, deep into the Nevada desert, has coated everything in a fine layer of grit.
It's 7:06 a.m. A scientist from Lawrence Livermore National Laboratory has just arrived at a remote facility built for a single purpose: to measure an event that no human can fully witness. A dry wind gusts across his face one last time before he steps inside the doors of the concrete building.
He runs through his checklist: materials shaped and delivered, systems aligned, and diagnostics tuned to capture a moment too fast for human senses to register. The data collected will ripple far beyond the harsh Nevada desert and directly influence national security. He's made this trek many times before, but today is different. Today is the day that three years of preparation culminate in less than a microsecond. Today is the day a two-stage gas gun drives a radioactive hazardous material into conditions too extreme to observe directly.
Today is the day they measure plutonium.
Today is Shot Day at Jasper.
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An unmanned test vehicle tears out of the atmosphere.
In the vacuum of space, it's silent as it makes its way back to Earth. Then, it hits. Reentry. The air doesn't part, it compresses. Temperature spikes, the surface begins to burn. The vehicle, and whatever it could have told us, gone.
Back in the 60s, the space race, people wanted ways to test reentry nose cones.
As missile programs and early spaceflight pushed beyond the atmosphere, reentry became one of the hardest problems to solve.
Typically, if you have something from space falling back to Earth, it might be 11 kilometers per second.
The US government turned to General Motors, looking for another way. Not to chase a moment in the sky, but to recreate it on the ground. Using the same principle as a cannon, they compressed gas to launch a projectile at extreme speeds, fast enough to mimic the shock of reentry.
Gas guns, eventually making their way to Lawrence Livermore National Laboratory, where the technology was expanded, refined, and adapted for entirely new kinds of experiments.
That gun should have a Chevrolet stamp on it because it was made by General Motors.
Ricky Chow is the execution lead at Jasper.
General Motors, what they've done with these test guns, they donated them to the Department of Energy. So the guns that we have here were prototypes of the launcher.
But what they were built for then, isn't what they're used for now. For more than 20 years, far removed from city lights and ordinary laboratories, the Joint Actonide Shock Physics Experimental Research Facility, or JASPER, has done something no other place on Earth can do: study plutonium with extraordinary precision, in complete containment, without nuclear testing.
In the old days, you could use rough guesses for the data, because, well, if you're not sure, we're gonna blow one of them up and then we'll just verify our models against the test. Once you stop being able to do that, and the further you go away from that, then your models have to get better.
Few materials arrive with as much baggage as plutonium.
You are the target. You will be prepared.
Mushroom clouds, fallout shelters.
Waiting out decay.
Yellow and black radiation signs, and the long afterimage of the atomic age. Atomic bombs could cause serious damage. It's a highly radioactive heavy metal.
Plutonium! Are you telling me that this sucker is nuclear?
It's handled under some of the strictest protections the US government can impose. And it's toxic. At Jasper, every step must be controlled.
Jasper is the only gun in the United States that can hit this broader range of velocities and be used on plutonium.
Meet David Boebert, the team lead for Jasper.
A Jasper target typically starts its life cycle as some source of plutonium. Could be a casting that we've made specifically for these sorts of science experiments. And that will then be brought into a glove box. The image in the public mind is the intro to Homer Simpson.
All I need is some plutonium.
He's got his hands in the gloves in the big window. It's that, but done by professionals.
Once it's prepared, the experiment begins.
Jasper is an impact-driven launcher, impact-driven experiments. So we throw a projectile at up to eight kilometers per second at the target.
18,000 miles per hour ejected by a two-stage gas gun.
You hit a fire button, it sends a fire pulse through the electronics. And in Jasper's case, it sets off a detonator, commercial detonator. The first stage is like a large cannon, like a howitzer or a battleship gun. It works the same way. You have a propellant charge, we wrap it up, it looks like a giant burrito. We fill it with priming powder. We use commercial sporting goods, like hunter powder. And then we fill a 30 odd six cartridge with the same powder and stick it in the back. And all we do is we have a solenoid that acts like a hammer of a gun that hits the back of the 30 odd six, and that's what fires the gun. The primer on the cartridge, it lights the primer powder, the primer powder burns, the flames go out the holes, and then it lights the main charge.
The fire command starts the first stage. The second stage comes only milliseconds later, once the piston has compressed the hydrogen gas.
The propellant starts to burn, and it's in a breach, which is a sealed volume. So as you create more burn gases, pressure builds up. Then the pressure is going to push on a piston. And then so this piston starts traveling due to the burning gases. At some point, you increase the pressure so high, and then the gases escape into a tapered section and acts just like a perfume nozzle, so that you have gases going through and accelerates the gas. And that accelerated gas then pushes on a little inch in diameter projectile.
The pressure going through is so high that it ruptures a pedal valve that launches the projectile.
And that's what gets launched at 800 per second. Fire. And then it goes down to the barrel, comes out of the gun, and it smacks the target. And then it flies through some x-ray and laser diagnostics just to measure the velocity, you know, like basically like two I-beams. You break one beam, get a counter, break another beam, that gives you your velocity.
The whole sequence is designed to do one thing relentlessly well: turn stored energy into extreme speed.
The old magic trick where the magician pretends to catch a bullet in their teeth, we're really doing that, but this bullet is traveling 10 times faster than a rifle bullet. The portion of time where we are collecting useful data is less than a microsecond or one millionth of a second, and that's actually maybe for our slower experiments. Some of the more typical experiments, it's more like 100 nanoseconds. So a typical experiment for us would be, we may be measuring the speed of a shockwave as it transits through a sample. So we'll measure very precisely the moment of impact, and then we'll measure how long it takes for that shockwave that's generated to transit across the sample. And that tells us something important about the thermodynamic state.
In a fraction of a microsecond, plutonium is pushed into extremes too fast to see and too important to guess at.
You can imagine a shockwave like, imagine a snowplow driving down the street. The snow has fallen overnight, the road is covered in a nice even layer of it. As the snowplow goes, the snowplow blade moves at a certain velocity and the snow piles up in front of it and it compacts. And as it compacts, you can imagine that wave starts to move forward away from the plow. So the farther the plow moves, now there's this wave traveling forward of compacted snow. That disturbance is what we're looking at, where you go from unmoved snow to compacted slab.
The shot only matters if the diagnostics can capture it clearly enough to make the result repeatable, credible, and useful.
And when you do that, it makes an astounding mess. When a projectile hits something going a kilometers per second, people sometimes ask me what's left afterwards. What's left is almost nothing. The target's essentially exploded. So you've taken your target, you've in some cases vaporized it, you've mixed it with soot, everything else is more or less burned and it's embedded as tiny particles around whatever it was in when you shot it.
Which is why creating the shot is only half the challenge. Containing it is the other half.
What makes Jasper really audacious was that the people who conceived of this knew that. They had experience with those sorts of gun experiments. And they imagined a way in which they could do it on plutonium and capture every last tiny speck of that material and prevent it escaping into the environment.
At Jasper, containment is not just part of the design. It is the thing the entire experiment depends on. The diagnostics matter. The timing matters. The data matters. But none of it matters unless the material stays contained.
At Jasper, containment is non-negotiable.
If you want to reuse your gun, your containment strategy has to somehow cope with that. You have to admit the projectile, but not emit the contamination.
The shot has to get in, but nothing can come out. Something that, at one point, sounded impossible.
Sometimes when I drive to work, I try and imagine, how was that meeting when this was proposed? And I think what I come back to over and over again is that when you want to know how important this is, it's important enough that someone was able to propose that idea, and the answer was, yeah, let's think about that. And then it got done.
The team at Jasper has not only met the goals of their original mission, they've gone far beyond its original expectations, cutting uncertainty by more than 50% from its initial targets.
I can smack plutonium all you want. If I don't have diagnostics, all I've done is just create nuclear waste.
Trust is not a feeling. It is built shot by shot through repeatability, transparency, and uncertainty small enough that other programs can confidently build on the result.
We're using really well-proven tools. So the science behind this dates back decades. So we try to be very open about how big our error bars are. And we try to be really transparent in everything that goes into that uncertainty. I can tell you a thing is an inch long, but if it's an inch plus or minus a mile, that's not that useful. Historically, the shock physics community has not maybe done as good a job about that as we should. I think that has changed, and I think Jasper was one of the ways that helped that change.
Jasper's mission is to generate data precise enough to reduce uncertainty and strong enough to anchor decisions across the stockpile stewardship and modernization community.
By the time we actually produce the data, there's a lot of evidence to show that what we claim to be measuring really is what we're measuring.
I make an effort of going out there periodically, giving these briefings to people so that they understand how their work impacted the overall program. And I will show them the data and show them the impact. This is data we took. This is how headquarters received it. This is the result of this measurement. And when you tell those guys that your measurements prove that the PU behaved properly, you see it in their eyes.
The success also depends on a close partnership with the Nevada National Security Sites, or the NNSS, whose operational expertise and support help make these complex experiments possible.
In practice, that relationship works better than you might think. Because while we have separate budgets coming from the federal government, I think both sides of that relationship realize that you can't row with one oar. We do a good job cooperating.
As diagnostics improved, the picture sharpened.
As priorities shifted, the questions expanded. And as the data became more precise and repeatable, Jasper's role grew with it.
Other questions like temperature, that's a much harder question. That's been a holy grail for the shock physics community, not even just plutonium. It's almost anything, shocking anything and trying to measure accurate temperature. We've had to develop new street cameras that are coupled with spectrometers, infrared detectors for lower temperatures. So the needs of the experiment drive the development of diagnostics.
What started as a way to answer a narrow set of questions became a facility capable of answering many more about aging, manufacturing, material strength, and the future needs of the stockpile.
It came online in the early 2000s. We were in the middle of obtaining the data on the various materials. How Jasper fits in now versus then is that once you've created the capability, other problems pop up. And then Jasper was the right facility to answer these questions. So the first one that was outside the original Jasper program was an idea that's still with us today is the idea of what happens when your plutonium gets old? Does it behave the same? And Neil Holmes says, well, we have this Jasper facility that we're getting very high accuracy. We could do an experiment that we can compare new and old plutonium. And that was the first branching off point.
The future of Jasper is not only new questions, but new ways of measuring them.
There are changes afoot in the nuclear weapons complex. We're building new pits, for example. Many of the existing weapons are quite old. The questions that are being asked related to things like new manufacturing and aging, those have influenced the sorts of science that Jasper and facilities with similar missions are doing.
What began as a way to answer shock physics questions has transformed into one of the nation's most trusted tools for understanding plutonium. The event at its center unfolds in less than a microsecond. And yet, that moment becomes data scientists can trust. What leaves Jasper isn't the shot itself. It's the understanding that remains after it.
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Page updated October 30, 2026 · transcript and summary are machine-generated