Fusion power has been thirty years away for roughly sixty years. This is the single most cited fact about the field, deployed by skeptics with the confidence of someone who has discovered a devastating argument that the entire fusion research community somehow failed to consider. The joke is real. The timeline failure is real. And the underlying implication—that fusion is a perpetual mirage, always receding as you approach it—is no longer accurate, though you’d be forgiven for not believing that given the track record.

Here’s what changed: in December 2022, the National Ignition Facility at Lawrence Livermore National Laboratory achieved ignition—a fusion reaction that produced more energy than was delivered to the fuel. In 2025, Commonwealth Fusion Systems completed its first high-temperature superconducting magnet and began assembling SPARC, a compact tokamak that the company says will achieve net energy in 2027. Private fusion investment has exceeded $10 billion since 2021. Helion Energy is building a plant to deliver 50 megawatts to Microsoft data centers by 2028. Google, Nvidia, Sam Altman, Bill Gates, and—in a plot twist that nobody anticipated—the Trump family have all put money into fusion companies. The Fusion Industry Association now has 45 member companies.

Something is different this time. Whether that something is sufficient to close the gap between “it works in a lab” and “it powers your house” is the question that matters, and answering it honestly requires understanding why the gap has been so persistent in the first place.

What fusion is and why it’s hard (the 90-second version)

Fusion is the process that powers the sun. You take light atomic nuclei—typically isotopes of hydrogen—and force them together at temperatures exceeding 100 million degrees Celsius until they fuse into heavier nuclei, releasing enormous amounts of energy in the process. The fuel is abundant (deuterium comes from seawater, tritium can be bred from lithium), the energy density is extraordinary (a few grams of fuel produces as much energy as tons of coal), and the waste products are helium and neutrons rather than CO2 or long-lived radioactive waste. On paper, it’s the energy source that solves everything.

The problem is that “forcing nuclei together” requires overcoming the electromagnetic repulsion between positively charged protons, which means you need to create and sustain a plasma—a gas so hot that electrons are stripped from atoms—at temperatures roughly ten times hotter than the center of the sun, and you need to confine that plasma long enough and at sufficient density for enough fusion reactions to occur to produce net energy. The sun accomplishes this through gravity. It has 1.3 million times the volume of Earth pressing inward on its core. We don’t have that luxury, so we have to use either magnetic fields or inertial compression to do the job, and both approaches are engineering nightmares of the first order.

The measure of success is Q—the ratio of fusion energy produced to the energy required to heat and confine the plasma. Q > 1 means you’re getting more out than you’re putting in. Q > 10 means you’re getting enough out to run a practical power plant after accounting for conversion losses and plant operations. NIF achieved Q ≈ 1.5 in its best shot. ITER, the international tokamak under construction in France, is designed for Q ≥ 10. SPARC is targeting Q > 2 as a demonstration, with the expectation that its commercial successor, ARC, will operate at Q > 10.

Why it’s taken so long

The conventional answer is “it’s really hard physics.” That’s true but incomplete. The more complete answer involves three factors that have nothing to do with plasma physics.

Funding volatility. Fusion research has been subject to boom-and-bust funding cycles since the 1970s. In 1976, the U.S. Energy Research and Development Administration published a report projecting timelines for fusion based on different funding levels. The “fusion never” line corresponded to flat or declining budgets. The actual funding trajectory for the next four decades tracked almost exactly along the “fusion never” line. The thirty-years-away joke is less a reflection of the physics being intractable and more a reflection of the fact that governments kept funding the field at the level that their own projections said would produce no result. Fusion researchers have been trying to build a reactor on a budget calibrated to produce a perpetual research program instead.

ITER’s governance structure. ITER is a collaboration among 35 nations, which means it’s simultaneously one of the most ambitious scientific projects ever undertaken and one of the most bureaucratically encumbered. Components are manufactured across multiple countries, shipped to southern France, and assembled according to specifications that were locked in over a decade ago. The project is billions over budget and years behind schedule. First plasma is now expected sometime in the next decade—decades after the project was conceived. ITER may ultimately demonstrate Q ≥ 10, and if it does, it will validate the tokamak concept at reactor scale. But it will not have done so quickly, cheaply, or in a way that suggests the model is replicable for commercial deployment.

The tritium problem. Most fusion reactor designs use deuterium-tritium fuel because the D-T reaction has the lowest ignition temperature and highest cross-section—it’s the easiest fusion reaction to achieve. But tritium doesn’t exist naturally in useful quantities. It’s radioactive with a half-life of 12.3 years and is currently produced almost exclusively as a byproduct of heavy-water fission reactors, primarily in Canada. The global supply is roughly 25 kilograms. A single fusion power plant would consume 50 to 100 kilograms per year. The plan is for fusion reactors to breed their own tritium by surrounding the plasma chamber with a lithium blanket that captures the neutrons produced by fusion and transmutes lithium into tritium. This breeding cycle has never been demonstrated at scale, and achieving a tritium breeding ratio greater than 1.0—producing more tritium than you consume—is an unsolved engineering challenge that every D-T fusion design depends on.

What’s actually close

Commonwealth Fusion Systems is the company most likely to demonstrate net energy fusion in a tokamak in the near term. SPARC is roughly 60 percent complete as of early 2026. The first of 18 toroidal field magnets has been installed. The cryostat base—the structural foundation that supports the 1,000-tonne tokamak—is in place. The company expects all 18 magnets installed by mid-2026, first plasma in 2027, and net energy demonstration shortly after. SPARC is designed to achieve Q > 2 in pulses lasting roughly 10 seconds, possibly extending to 30 seconds—though at 30 seconds, heat loading on the inner wall becomes a problem because the SPARC chamber is compact and the neutron flux is intense.

The key innovation is the magnet. SPARC uses high-temperature superconducting (HTS) tape—specifically REBCO (rare-earth barium copper oxide) superconductor—to produce magnetic fields roughly twice as strong as ITER’s conventional superconducting magnets. Stronger fields mean you can confine the same plasma in a much smaller volume, which means a much smaller, cheaper, faster-to-build machine. SPARC is about 24 feet across. ITER is the size of a building. CFS demonstrated a full-scale HTS magnet producing a field of 20 tesla in September 2021, which was the engineering milestone that convinced most of the fusion physics community that the compact tokamak approach was viable. The company has raised nearly $3 billion, including investments from Google, Nvidia, and Breakthrough Energy Ventures.

If SPARC succeeds, the commercial plant is ARC—a 400-megawatt machine planned for a site in Chesterfield County, Virginia, in collaboration with Dominion Energy, with grid power targeted for the early 2030s. Google has signed a 200-megawatt power purchase agreement. That’s not a research grant. That’s a customer.

Helion Energy is taking a fundamentally different approach—pulsed field-reversed configuration fusion, using deuterium and helium-3 fuel instead of deuterium-tritium, which avoids the tritium supply problem entirely but requires a much harder fusion reaction to achieve. Helion has signed a power purchase agreement with Microsoft to deliver 50 megawatts from its Polaris plant in Washington state by 2028, backed by $425 million in funding led by Sam Altman. Whether Helion can achieve its stated timeline is an open question—the field-reversed configuration approach has less experimental history than the tokamak, and the company’s claims have drawn skepticism from mainstream fusion physicists.

TAE Technologies, in one of the stranger corporate developments of 2025, merged with Trump Media & Technology Group in a $6 billion deal that will make it the first publicly traded fusion company—and partially owned by the Trump family. TAE uses a beam-driven field-reversed configuration targeting proton-boron-11 fusion, which is aneutronic (no neutrons, no radioactive waste, no tritium needed) but requires even higher temperatures than D-T and has even less experimental validation. The merger injects capital into a company that has been operating for over two decades; whether it injects physics remains to be seen.

Pacific Fusion, one of the newest entrants, raised $900 million in Series A funding—the largest initial round in fusion history—from Eric Schmidt, Patrick Collison, Reid Hoffman, and other Silicon Valley investors. Pacific is pursuing inertial confinement fusion, the approach used by NIF, but with a pulsed power driver instead of lasers. The company is deliberately quiet about its technical details, which is either prudent IP protection or a sign that the details don’t yet support the valuation.

The “done” question

Here’s the part that most fusion coverage skips: achieving Q > 1 is not the finish line. It’s the starting line. A fusion reaction that produces net energy for 10 seconds in a laboratory is a physics milestone. A fusion power plant that produces net electricity, continuously, reliably, for decades, at a cost competitive with fission, natural gas, and renewables—that’s a different problem entirely, and it involves challenges that have nothing to do with plasma physics.

Materials. The inner wall of a fusion reactor is exposed to a neutron flux that degrades materials at a rate for which we have almost no operational data, because no fusion machine has run long enough at high enough power to test it. ITER’s plasma-facing components use beryllium and tungsten, and even those are expected to require periodic replacement.

Maintenance. A fusion reactor is radioactive—not from the fuel, but from the neutron activation of structural materials. Maintenance must be performed robotically behind heavy shielding, on a machine operating at temperatures from minus 269°C (the magnets) to 100 million degrees (the plasma) with everything in between.

Electricity conversion. Fusion produces heat. That heat must be captured and converted to electricity through steam turbines or another thermal cycle, which means the plant has all the complexity of a conventional thermal power plant in addition to the fusion-specific systems. The overall electrical efficiency—from fusion energy produced to electricity delivered to the grid—must be high enough that the plant is economically viable after paying for fuel, operations, maintenance, and capital costs.

Regulatory framework. There is currently no licensing pathway for commercial fusion plants in most countries. The U.S. Nuclear Regulatory Commission has been working on a framework, but it’s not finalized. You can’t build a power plant if there’s no regulatory process for approving it.

None of these problems is unsolvable. All of them are the kind of grinding, unglamorous engineering challenges that don’t generate press releases or attract venture capital but determine whether a technology actually ships. The gap between “SPARC achieves Q > 2 in 2027” and “you can buy electricity from a fusion plant” is measured in these problems, and the honest estimate for closing that gap—from the most optimistic credible voices in the field—is the early to mid 2030s, with widespread deployment following over the subsequent decade.

Kim Budil, the director of Lawrence Livermore, put it well at Davos in early 2026: “Historically, we’ve always said fusion energy is 30 years away from whatever day you ask and will always be that. I think that’s not true anymore. But fusion is hard. There’s a lot of work to be done.”

That’s the right framing. Not “it’s here.” Not “it’ll never happen.” It’s close in a way it has never been close before, the money is real, the engineering is advancing, and the physics has been demonstrated. But the path from physics demonstration to power plant passes through a decade of materials science, manufacturing, regulation, and the kind of reliability engineering that turns a prototype into something that runs on a random Tuesday without a team of PhDs babysitting it.

We cover fusion power in depth—the physics, the engineering, the economics, every company and approach, and the constraints that determine whether any of it actually reaches the grid—as the opening lecture of our Moonshot 2169 course. If the thirty-years-away joke bothers you as much as it should, that’s the place to get the full picture.

The U.S. Space Force reports that its satellites experience jamming, dazzling, or other hostile electronic interference on a daily or near-daily basis. Not occasionally. Not during heightened tensions. As a routine operational reality, every day, somebody—and the “somebody” is almost always China or Russia—is attempting to degrade, disrupt, or blind American space-based assets. GPS signals are spoofed. Communications links are jammed. Sensor systems are targeted with directed-energy weapons designed to temporarily overwhelm their optics. None of this involves explosions. None of it generates debris. None of it makes the news. And all of it is, by any functional definition, warfare—conducted in orbit, against military infrastructure, by state actors with the explicit goal of degrading an adversary’s capability.

Space warfare isn’t coming. It’s here. It just doesn’t look like Star Wars. It looks like an electromagnetic interference report filed by a satellite operations center in Colorado Springs at 3 AM on a Tuesday, which is less cinematic but considerably more consequential.

Why space matters militarily (the version nobody skips)

Every precision-guided munition the U.S. military fires depends on GPS satellites for navigation. Every drone feeds its sensor data through satellite communications links. Every early-warning system that detects a ballistic missile launch does so with space-based infrared sensors that spot the thermal signature of a rocket plume within seconds of ignition. Every intelligence assessment of enemy force disposition relies on satellite imagery. The U.S. military doesn’t just use space—it is architecturally dependent on space in a way that no other military in history has been dependent on a single domain.

This creates an asymmetry that China and Russia have studied carefully and concluded is a vulnerability worth exploiting. If you can deny an adversary access to its space-based assets—its GPS, its communications, its surveillance, its missile warning—you don’t have to match it capability-for-capability on the ground, at sea, or in the air. You just have to blind it. A carrier strike group without satellite communications and GPS-guided weapons is a very expensive collection of ships that can’t coordinate, can’t navigate precisely, and can’t hit anything beyond visual range. The entire American way of war since the first Gulf War has been built on the assumption that space-based services will be available, uninterrupted, when needed. That assumption is now the single most attractive target in the U.S. military architecture.

What countries are actually doing

The Secure World Foundation’s 2025 Global Counterspace Capabilities report—the publication of record on this topic—documents counterspace programs in 12 countries. The three that matter most are China, Russia, and the United States, though India, France, Japan, and others are developing capabilities.

China conducted a direct-ascent anti-satellite missile test in 2007, destroying one of its own defunct weather satellites at an altitude of roughly 865 kilometers. The test was a technical success and a diplomatic disaster—it created nearly a thousand pieces of trackable debris, much of which is still in orbit and will remain there for decades, endangering every satellite in that altitude band including China’s own. The test was not a surprise to U.S. intelligence, which had been warning since 2003 that Beijing was developing this capability. What it demonstrated was intent: China was willing to create a permanent debris hazard in its own operating environment to signal that it could kill satellites.

Since then, China has moved significantly beyond kinetic kill vehicles. Its military now operates satellites capable of what the Space Force calls “dogfighting”—maneuvering in proximity to other nations’ satellites, inspecting them, and potentially grabbing them and dragging them into graveyard orbits. The Secure World Foundation documented five Chinese satellites conducting rendezvous and proximity operations throughout 2024. China routinely employs ground-based jammers targeting satellite communications, radar, and navigation systems, including the Pentagon’s extremely high-frequency systems. Ground-based lasers capable of dazzling or damaging satellite optical sensors are in development and could be deployed before the end of the decade. China’s operational satellite fleet exceeded 1,060 by mid-2025, with hundreds dedicated to intelligence, surveillance, and reconnaissance—building what Space Force leadership describes as a “kill web” that uses hundreds of satellites to find, track, and target forces on Earth.

Russia has its own portfolio. The Peresvet, a ground-based high-energy laser system deployed with mobile ICBM units, is designed to dazzle the optical sensors of reconnaissance satellites that would otherwise track Russia’s nuclear missile launchers. Russia has demonstrated co-orbital anti-satellite capability through its Luch satellite program, which has conducted proximity operations against Western communications satellites in geostationary orbit. In November 2021, Russia conducted a direct-ascent ASAT test against one of its own satellites, creating over 1,500 pieces of trackable debris and forcing the International Space Station crew to shelter in their evacuation vehicles. The test drew universal condemnation, including from China.

The most alarming Russian development, however, is the reported nuclear anti-satellite weapon. U.S. intelligence confirmed in February 2024 that Russia is developing a satellite designed to carry a nuclear warhead into orbit—not to use against targets on Earth, but to detonate in space and destroy or disable satellites across a wide orbital zone through electromagnetic pulse. A nuclear detonation in low Earth orbit would be indiscriminate—it would fry not just American military satellites but commercial satellites, allied satellites, and Russian satellites. It would generate an EMP across hundreds of kilometers of orbital altitude, potentially rendering entire orbital shells unusable. The Outer Space Treaty of 1967 explicitly prohibits placing nuclear weapons in orbit. Russia ratified that treaty. Whether that matters in practice is a question the treaty wasn’t designed to answer.

The United States has historically been more circumspect about its offensive space capabilities—which, given the classification levels involved, means we know less about what the U.S. can do than what China and Russia can do. What’s publicly known: the Space Force operates the GSSAP (Geosynchronous Space Situational Awareness Program) satellites, which conduct proximity operations in geostationary orbit and are officially described as a “neighborhood watch,” though their maneuvering capabilities are consistent with inspection and potentially interference missions. The X-37B, an autonomous reusable spaceplane operated by the Space Force, has completed multiple extended missions in orbit—the most recent lasting over 900 days—with mission objectives that remain classified. The Space Force announced in early 2026 that it is deploying three electronic satellite jammers, the first acknowledged offensive counterspace weapons in the U.S. arsenal. Under the Trump administration’s “Golden Dome for America” missile defense initiative, boost-phase interceptor prototypes—weapons designed to destroy enemy ballistic missiles from space during the first minutes of flight—were awarded under competitive contracts in late 2025.

Space Force Chief of Space Operations General Chance Saltzman has been remarkably direct about where this is heading. At the Air and Space Forces Association Warfare Symposium in March 2025, he declared that the Space Force “will do whatever it takes to achieve space superiority.” In testimony before the U.S.-China Economic and Security Review Commission, he described the need to develop systems that can deny China’s use of its space assets—not just protect American satellites, but actively degrade an adversary’s space architecture. That’s a significant escalation in stated policy from “protect our stuff” to “break their stuff.”

The Kessler problem

Every kinetic anti-satellite test—every satellite physically destroyed in orbit—generates debris that travels at orbital velocity (roughly 28,000 kilometers per hour in low Earth orbit) and remains in orbit for years to decades depending on altitude. A bolt traveling at that speed carries the kinetic energy of a hand grenade. The four countries that have conducted destructive ASAT tests—the U.S., Russia, China, and India—have collectively created 6,851 catalogued pieces of trackable debris, of which 2,920 are still in orbit as of the 2025 Secure World Foundation report.

The Kessler syndrome, proposed by NASA scientist Donald Kessler in 1978, describes a scenario in which the density of debris in orbit becomes high enough that collisions between objects generate more debris, which causes more collisions, in a cascading chain reaction that eventually renders entire orbital shells unusable. We’re not there yet. But every destructive ASAT test moves the needle closer, and the 2007 Chinese test and 2021 Russian test together represent the two largest single contributions to the orbital debris environment in history.

This is why the Space Force publicly states that kinetic destruction of enemy satellites is a last resort—the debris affects everyone, including the country that created it. The preferred tools are reversible: jamming, spoofing, dazzling, cyber intrusion. Blind the satellite temporarily rather than blow it up permanently. The problem is that “reversible” tools don’t provide the deterrent clarity that “we destroyed your satellite” does, which creates a strategic ambiguity that makes escalation management in space considerably harder than it is in other domains. If someone jams your satellite and then stops, was that an act of war or a provocation? The answer matters, and nobody has established the norms to answer it.

Starlink changed the equation

The war in Ukraine demonstrated something that military planners had theorized but never seen in practice: a commercial satellite constellation can provide militarily critical communications capability that is extraordinarily difficult to destroy. Ukraine’s military used Starlink extensively for battlefield communications, drone coordination, and command-and-control functions. Russia attempted to jam it. The jamming had some effect—there were reports of service interruptions—but the constellation’s architecture made it resilient. Starlink operates thousands of small satellites in low Earth orbit, and destroying enough of them to meaningfully degrade the network would require an anti-satellite campaign of a scale that nobody has the inventory to conduct.

SpaceX subsequently developed Starshield, a version of Starlink designed specifically for national security applications, with enhanced encryption and anti-jamming features. The lesson that every military in the world drew from Ukraine was that proliferated constellations of small, cheap, replaceable satellites are dramatically harder to kill than traditional military satellites—large, expensive, few in number, and each representing a single point of failure. The Space Development Agency’s Tranche 3 tracking layer, a $3.5 billion investment for 72 new satellites awarded in late 2025, reflects this shift: distribute capability across many platforms so that losing any one of them doesn’t cripple the network.

Where this goes

The Space Force’s “Race to Resilience” initiative aims to achieve battle-ready space architectures by 2026—meaning satellite constellations that can absorb attacks and continue functioning, with the ability to reconstitute lost capability by launching replacement satellites on short notice. Four on-orbit servicing demonstrations are planned for 2026 to test satellite refueling, repair, inspection, and maneuvering—capabilities that are defensive in framing but dual-use in practice, because a satellite that can refuel a friendly satellite can also approach and interfere with a hostile one.

Germany committed 35 billion euros to low-Earth-orbit resilience and non-kinetic deterrence in early 2026. The U.S. Congress appropriated $250 million specifically for directed energy research and development that includes space-based applications. The Golden Dome initiative is exploring space-based missile interceptors. The trajectory is unmistakable: space is being weaponized, the major powers are building the tools to fight there, and the governance framework—the Outer Space Treaty, written in 1967 when the total number of objects in orbit could be counted in the hundreds—is not remotely equipped to manage a domain that now contains over 10,000 active satellites and is the operational backbone of every advanced military on the planet.

The conflict in space won’t look like a battle. It’ll look like a degradation—GPS accuracy declining by meters, then tens of meters, then failing entirely. Satellite imagery going dark over a region at the worst possible moment. Communications links dropping during a crisis. Early warning systems providing ambiguous data when clarity matters most. The weapons are invisible, the effects are deniable, and the consequences are catastrophic. That’s not a future scenario. Portions of it are happening right now, in orbit, every day, and the people tasked with responding to it are working out of a military branch that’s younger than most TikTok accounts.

We cover space warfare—alongside drones, directed energy weapons, electronic warfare, autonomous systems, and every other technology reshaping combat from 2025 to 2125—across 36 lectures in our Battlefields of the Future course. If the daily jamming reports or the nuclear ASAT program changed your mental model of what’s happening in orbit, that’s where the full picture lives.