Experts were skeptical of Lockheed Martin Corp.'s claims this week that it plans to build a fusion reactor small enough to fit on the back of a truck over the next decade.
The Bethesda, Maryland-based company -- the world's largest defense contractor, known for its stealth fighter jets and guided missiles -- on Wednesday announced that it would test a compact fusion reactor in less than a year, build a prototype in five years and deploy the system in 10 years.
Thomas McGuire, the man behind the project at Lockheed's famously secretive Skunk Works laboratory in Palmdale, California, was bullish on his team's approach to the nuclear technology, on which the company holds several patents.
Fusion energy has the potential to revolutionize how the military powers its fleets of ships, aircraft and ground vehicles, he said. "A next-generation airplane that doesn't rely on fuel and can just stay aloft -- unlimited range, unlimited endurance," he said in a promotional video. "That's what nuclear fusion can do for an airplane."
McGuire goes on: "Ten years, we have great military vehicles. Twenty years, we have clean power for the world."
Others were less optimistic. After all, creating a fusion reaction in a controlled environment that produces more energy than it consumes has challenged physicists since the dawn of the Atomic Age.
"I'm surprised that a company like this would release something that doesn't have much context," said Steven Cowley, a professor in plasma physics at the Imperial College London, director of the Culham Centre for Fusion Energy in Oxfordshire, United Kingdom, and a leading expert in magnetic fusion energy.
"Normally, if someone says they're doing well in fusion, they would quote some data, 'We got a temperature of x and a confinement of y,'" he said, referring to how long a reactor can hold the heat of a reaction before it escapes. "There's no such information."
Fusion, which occurs naturally on the sun and makes energy by fusing atoms, is basically the opposite of fission, which creates energy by splitting them. The latter is the foundation for modern nuclear technology and, for decades, has been used to power everything from aircraft carriers to commercial power plants.
Fusion has long been an attractive potential energy source to physicists because such a reactor could theoretically run on the same kind of hydrogen found in ocean water, produce little waste and avoid a catastrophic meltdown because the process doesn't lend itself to out-of-control chain reactions.
Earlier this year, scientists at Lawrence Livermore National Laboratory in California reported a breakthrough by generating a fusion reaction that created more energy than it started with. But the experiment didn't produce enough power to have practical implications.
What's more, it required far more energy to get the reaction going. (Scientists concentrated 192 lasers on a pellet of hydrogen fuel to compress it and trigger a fusion of the isotopes deuterium and tritium. Only about 1 percent of the energy from the lasers entered the pellet, but the technique, known as "alpha heating," created a series of nuclear reactions that generated a higher level of particles and heat.)
Even the best fusion experiment created less energy than it took in. The Joint European Torus, or JET, the world's largest magnetic confinement plasma physics project in Oxfordshire, in 1997 produced 16 megawatts of power for about two seconds while using 24 megawatts, Cowley said.
"The whole problem with fusion is holding something at 200 million degrees in a stable way and not letting the heat leak out," he said.
Based on the equipment shown in photographs and the video, Cowley said Lockheed appears to be working on a field-reverse configuration, or FRC, to test fusion by suspending plasma in magnetic fields. Used from the 1950s through the 1970s, the devices were unstable and produced a maximum confinement time of about 1 millisecond, he said.
Lockheed's McGuire describes the system as a "magnetic bottle."
The device "can contain high temperatures. You need hundreds of millions of degrees. We can release in a controlled fashion that energy," he said. "It's a high-beta concept, which means we use a high fraction of the magnetic field pressure. We use all of its potential, and that means we can make our devices 10 times smaller, so instead of something the size of a building, we have something the size of a large truck."
Yet even McGuire suggests the idea isn't exactly a reality. "This is a high-risk, high-payoff endeavor," he said. "That's what we're doing here, is testing that concept out to see if it really holds the promise that it appears to."
Cowley said decades of fusion research indicates the bigger the reactor, the better.
He's part of a team that's building a machine in southern France with superconducting coils that are 12 meters high. The $20 billion project, called the International Thermonuclear Experimental Reactor, or ITER, and slated to begin operations in 2024 in Cadarache, France, will be twice the size of JET and is designed to produce 500 megawatts of power while consuming less than 50 megawatts, he said.
"What we've learned by building lots of machines is that when you double the size of the machine, you make it confine the heat eight times better," he said. "I believe ITER is the best possibility of doing that. Somebody might come up with a really bright idea and do it a lot quicker and cheaper. But it's difficult to see at the moment."
Perhaps Lockheed was simply trying to drum up interest in the subject as part of an effort to seek more funding for its research.
McGuire and his team were reportedly working on fusion energy "for about four years, but were now going public to find potential partners in industry and government for their work," according to a Reuters article.
The company's marketing effort came a day after the U.S. Energy Department's Advanced Research Projects Agency, or ARPA-E accepted submissions for a $30 million award "to develop and demonstrate low-cost tools to aid in the development of fusion power." It wasn't immediately clear if Lockheed applied for the funding.
