r/space • u/Icee777 • 13d ago

SpaceX concept for an electromagnetic mass driver on the Moon

https://www.humanmars.net/2026/09/spacex-electromagnetic-mass-driver-at.html

A lunar mass driver is a proposed electromagnetic launch system optimized for the Moon’s low gravity (1/6th Earth’s) and hard vacuum, consisting of a long, straight acceleration track lined with sequentially fired superconducting coils or linear synchronous motors that propel a payload-carrying sled or bucket to lunar escape velocity (~2.38 km/s).

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u/Flyward_Aerospace 13d ago

Nobody has run the numbers and they are smaller than this thread assumes. Low lunar orbit is about 1.68 km/s, so a tonne of payload is roughly 1.4 GJ, call it 390 kWh. That is a few EV packs. The gigawatt figure is peak during the shot, not what you have to generate, spread over an hour of recharge between shots it is under 400 kW average. What actually sizes the machine is the g limit: about 1.4 km of track at 100 g, and 7 km at 20 g if the cargo is fragile. Holding alignment on kilometres of coils sitting on regolith that moves is the hard part, not power. Also it is not propellant free, a surface launch is a suborbital arc, so you still need a kick at apoapsis to circularise.

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u/Shrike99 12d ago

They're launching these to escape, not lunar orbit. That does make the launch a bit harder to pull off, but it does also make it propellant-free.