The Technology
Superconducting Mass Drivers Will Transform Launch
Solving The Force Problem
Extreme magnetic fields come from extreme current densities. Where normal magnets and wires resist high current levels, high temperature superconductors happily perform.
Millions of Pounds of Pressure
A 9 Tesla field can produce 4,700 pounds per square inch of magnetic pressure. Over the area of a one-meter stator, that’s millions of pounds of magnetic pressure.
- The CFS / MIT SPARC Fusion Reactor Runs at 20 -22 Tesla
- Highest Resolution MRI Machines run 7 Tesla
Solving the Wear Problem
Repeated use without need for inspection or maintenance requires a non-contact solution. The EML Mass Driver uses magnetic levitation similar to what can be found in maglev trains for package centering in the launch tube
Solving the Energy Storage Problem
Legacy approaches require storage of energy in massive capacitor banks. A superconducting coil is its own energy storage device.
Solving the Switching problem
The EML superconducting Quench Drive operates as solenoids repeatedly pulling the carrier sleeve forward. Each stator coil pulls the armature coil forward, in effect transferring the magnetic energy from the circulating current in the outer coil into kinetic energy of the moving armature. When the armature is pulled to the mid-point of the stator, the energy transfer will reduce the current to zero. The EML patent pending switching system keeps zero current at zero current. No current = no magnetic field. The armature continues to accelerate.
Zero Point Switching Changes the switch equation
- The Zero Point!
Pulling the Armature into the stator converts the Stators magnetic energy into Armatures kinetic energy – zero magnetic field = zero current - Keep Current at Zero
Departing armature will try to pull those electrons back into motion – creating a magnetic field – pulling the armature back - EML Quad Switch Technology
Keeps the Stator at Zero (or very low)
A First Principles Solution
(shown without cooling or maglev)
HTS Materials: From Scientific Breakthrough to Fusion-Driven Industrial Scale-Up
High-temperature superconductors (HTS) have moved from laboratory curiosity to one of the central enabling materials for compact fusion. One particular HTS material, REBCO (rare-earth barium copper oxide), did more than just raise critical temperature. It also created a practical route to very high magnetic fields where REBCO can carry electrical currents that far exceed the practical range of low-temperature superconductors.
The major engineering change has been the evolution from brittle ceramic material to second-generation coated conductor: a thin, textured REBCO film grown on a flexible metal substrate with buffer layers, silver, and copper stabilizer. This architecture solved much of the grain-boundary problem that limited early HTS materials. In the 2000s and 2010s, industry learned to make longer, more uniform tapes. In the 2020s, the focus shifted to higher in-field critical current, longer piece lengths, better defect tolerance, lower AC loss, stronger mechanical behavior, and cheaper production. Advanced pinning centers, thicker high-quality REBCO films, better deposition control, and new MOCVD and PLD manufacturing approaches are continuing to improve REBCO performance while lowering cost.
Fusion has the largest demand for REBCO. Compact tokamaks and other high-field fusion concepts need magnetic fields in the 15–25 T class, where REBCO is uniquely attractive. MIT and Commonwealth Fusion Systems demonstrated this shift dramatically with a large 20 T HTS magnet using about 267 km of REBCO tape.
Recent fusion-focused work reports 3.5× performance improvements in 50-meter advanced MOCVD tapes compared with typical commercial REBCO at 4.2 K and 20 T, with next steps aimed at scaling to 300-meter-plus piece lengths. Double-sided REBCO tapes and improved current sharing are being explored to reduce the number of stacked tapes required in large cables and to improve tolerance to defects.
REBCO tape cost dropped rapidly in the early pilot era, a 2022 materials working group showed about $360/kA-m in 2010, roughly $200/kA-m in 2021, and in 2025 fusion-conductor costs of $125/kA-m. $10/kA-m is the long-term target.
The outlook is therefore clear: HTS materials have crossed the threshold from “possible” to “strategic.” The next breakthroughs are not likely to be a single magic superconductor, but manufacturing scale, higher critical current per tape, longer uniform lengths, better radiation tolerance, and lower cost per kiloamp-meter. Fusion has created the initial demand and industrial scale-up is now finishing the job.
Cryocooling technology is rapidly advancing
Over the last twenty years, cryocoolers have moved from specialized laboratory hardware toward practical enabling equipment for superconducting magnets, quantum systems, space instruments, high-temperature superconductors, infrared sensors, MRI/NMR systems, and cryogen-free research platforms. The improvement has not come from one breakthrough alone. It has come from better bearings, oil-free and scroll compressors, improved regenerators and heat exchangers, pulse-tube designs with fewer moving cold parts, better modeling, and a larger industrial supplier base.
The most notable changes are performance and reduced form factor. Around the late 2000s, a high-end 4 K pulse-tube cryocooler delivering about 1 watt near 4.2 K was a strong result. By the early 2020s, commercial pulse-tube units reached roughly 2.7 W and then 5 W at 4.2 K. New hybrid 4 K systems now advertise still higher cooling capacity, up to about 9 W at 4.2 K. At higher temperatures, especially 20 K to 80 K, the progress is even more relevant for HTS systems because the thermodynamic penalty is lower and the available cooling power is much greater. All of these performance improvements have been accompanied by smaller packaging.
Efficiency has also improved, although it remains highly temperature dependent. Cryocoolers operating near 80 K can reach useful fractions of ideal Carnot efficiency. Modern 20 K systems are particularly important: examples include pulse-tube systems around 12% of Carnot and turbo-Brayton systems around 15–16% of Carnot. For superconducting power, magnets, launch-assist coils, space propellant storage, and other HTS applications, the engineering improvements, although in increments, represent a breakthrough in how these cryocooling systems can be used.
Cost has also improved particularly as total cost of ownership. The bigger system-level cost improvement is that modern cryocoolers reduce or eliminate dependence on liquid helium. That matters because helium supply, handling, refilling, quench management, downtime, and specialized infrastructure can dominate operating cost and risk.
FAILED ELECTROMAGNETIC LAUNCH TECHNOLOGIES
The Rail Gun
The rail gun is the simplest of all the designs, it is a projectile (armature) located between two rails. As power flows from one rail, through the projectile, into the other rail, a force, known as the Lorentz Force, pushes the projectile forward.
Critically, the rails and the projectile need to be in physical contact for the system to work. And the system is inherently low in efficiency. The energy that does not become motion, tends to become heat. At high power levels and high speeds, the arcing, plasma, and wear create limits on the number of times such a launcher can be used without needing to be rebuilt. Further, the detritus from the rail projectile interaction causes a “restrike” or new conductive path between the rails behind the armature robbing power and limiting higher velocities.
It was originally selected because it does not require the high speed high current switching problem to be resolved.
After review, the DoD quietly shuttered their research effort into high power and high-speed rail guns as the issues with robustness at high power levels and high speeds were found not to be resolvable.
The Induction Launcher
This technology is the basis of most electric motors today, including linear electric motors that could be used in a launcher. Also known as traveling wave launchers, the armature moves along in front of the EM wave like a surfer. At higher and higher frequencies, the armature moves faster and faster.
Unfortunately, again, there is no known way to switch very high current levels at very high frequencies necessary to reach high velocities.
In general, this is known as “the switching problem” and is common to all non-contact electromotive methods.
The Coil Launcher
A series of coils, if energized at exactly the right time, could push a launch package forward, each giving another boost to higher and higher velocities. First, it is difficult from a materials science perspective to aggressively push a long and small-diameter object without risk of collapse. (Pulling is better.)
Power needs to be stored so that it can quickly dump into each coil exactly when needed. Many hundreds of giant capacitors or ultra-capacitors might suffice. As with the Induction or Traveling Wave Launcher, the switching problem has been shown to be insurmountable at high current levels and velocities.
Finally, when designed as a resistive (not super conducting) solution they system has low efficiency as a matter of physics. The greater the current dumped into the coils the greater the resistance. This is both from heating and inductive resistance. This is a fundamental physics problem and is not resolvable by engineering.