In 1974, the late Princeton University professor and space visionary Gerard O'Neill proposed using electromagnetic rail guns to lob payloads from the moon.
O'Neill suggested using "mass drivers" based on a coil gun design to accelerate a non-magnetic object. One application for mass drivers was launching moon-derived materials into lunar orbit for in-space manufacturing. O'Neill also worked at MIT on mass drivers, along with colleague Henry H. Kolm, and a group of farsighted student volunteers, to fabricate their first mass driver prototype. Backed by grants from the Space Studies Institute, later prototypes improved on the mass driver concept.
