Elon Musk isn't the first person to propose the use of mass drivers on the moon. He's following in the footsteps of space visionary Gerard O'Neill, who floated the idea back in 1974.

Elon Musk wants to put a satellite catapult on the moon. It's not a new idea

Source: space
Source Link: https://www.space.com/astronomy/moon/elon-musk-wants-to-put-a-satellite-catapult-on-the-moon-its-not-a-new-idea