A thought occurred to me after my post about recycling.
I proposed a system where rockets, fueled by hydrogen and oxygen, would take our trash into orbit, to be processed into new materials, and then returned to Earth for us to use.
It would be easier, cheaper, and faster to use a rail-gun instead. Sometimes called a linear accelerator, a linear electric motor, or another name that escapes me at the moment, it works on the same principle as a magnetic-levitation train. Essentially, it's a long, flat electric motor, with rails like those used for trains, and the payload is accelerated along its length, until at the end, the rails turns upward, and the payload is shot into the air, and if powerful enough, into Earth orbit.
To recap the concept, solar and/or wind power, which is basically free to use after installation, makes electricity, which is then stored in a giant mega-capacitor, until a launch is scheduled. At launch time, the capacitor is discharged into the rail-gun, and the payload of trash is accelerated down its length, and then upward into orbit, where the solar furnace and plasma printer are located. Then, in a manner resembling our current space shuttle, the launch vehicle glides to Earth with the newly-made materials on-board.
So much easier than rocket launches. A much cleaner method of getting stuff into orbit.