Rocket company develops massive catapult to launch satellites into space without using jet fuel

[ChazInAz]

4. The whole thing looks like a boondoggle.

A vacuum chamber that size, with multiple openings for bearings and a tangential exit, strikes me as being improbable. Then there are the challenges of getting an arm spinning at supersonic speeds, and the changing directional forces on any high-tech equipment installed in a payload.