The moon’s shallow gravity well means exit velocities with as little as 1.7 km/s are sufficient for launch to orbit. Slightly more, and you can deliver raw materials anywhere in the solar system. Engineering difficulties grow exponentially with launch velocity, so it is hard to overstate the advantage of low orbital velocity over Earth, where orbital velocities of nearly 8 km/s are required.
Further, the moon’s ever-present vacuum and abundant sunshine for solar electric power greatly enable this low-cost launch technology.
NASA and others are committed to returning to the moon; this means commercialization is necessary. An enormous market need for raw materials (water, fuel, metals, and oxygen) on lunar and Earth orbits, at Lagrange points, and for Mars settlement is projected. Our launching technology is synergistic with early investments in lunar mining and in situ materials processing.
Earth launch was the original application for electromagnetic launch. Long before we understood the pitfalls of previous approaches and the opportunity to use high-temperature superconductors, Earth launch was the focus.
It will require a small “third stage” rocket motor for additional delta V and to overcome atmospheric drag. This is true both because acceleration to higher orbital velocities is geometrically harder and because the launch of orbital velocity cargo without control for circularization and final delta V in an ever-more-crowded Earth orbit is unthinkable.
Such a system would operate at costs of just a few dollars per pound to orbit for raw materials, transforming the space industry. The key economic drivers are high yearly tonnage, robust low-maintenance operation, delivery cylinders made of useful materials on orbit (upcycled or recycled), and low cost or return of reusable small third-stage rocket motors.
Defense was the first use case for electromagnetic launch efforts. Early on, the defense department recognized that chemical propellants had reached their limits and started the first rail gun research efforts. This research was accelerated by President Reagan’s Strategic Defense Initiative, a.k.a. Star Wars. While rail gun efforts did not prove fruitful, much was learned.
The inherent benefits of an electromagnetic approach remain true today.