lunar mining

[backtrax]

In the SHARP project the propellent wasn't cordite or solid-fuels.
Methane was ignited, compressing a light-gas Via piston, overcoming a mechanical-coupling holding the projectile in place, in an evacuated chamber/barrel. The barrel-end was capped by plastic-seal that bursts on impact.
....Mach 8.8 speeds, but alot of friction from air once it left the barrel.