There are ideas to fire supplies into orbit from guns of various sorts, and generally the idea is to do it for things like water, or fuel which are much more valuable in orbit than on Earth, and can withstand just about any level of acceleration.

We also have electronics able to withstand high levels of acceleration which could be used once it’s in orbit. I don’t think we are “close” to this, but it doesn’t seem impossible to me.

For passengers and more fragile cargo, then there’s the idea of a maglev train that lets you accelerate most of the way into orbit along a track, which is not that different from the idea of a railgun. This is a mega structure, not unlike the Space Elevator, but with the difference that it could be built using existing materials, while the Space Elevator requires materials we may have some time in the next few decades.

The estimated costs are enormous of course, but not quite as huge as you might imagine perhaps. You would need a lot of demand to pay back the costs, but they could reduce the costs to orbit hugely. And of course - as mega structures, they would be very visible huge things, and permanent or semi permanent, so there is the question of whether that’s visually acceptable. You could build them over remote desert areas or the sea to deal with safety issues. I don’t see this as likely any time in the very near future. But if you take a larger timescale of many decades or centuries, who knows, especially if we have large numbers of people, and industry in space by then.

LAUNCH LOOP OR MAGLEV TRACK TO ORBIT

A Maglev train is a natural for acceleration to super fast speeds of kilometers per second - as it has no on board fuel, gets all its energy from the track so no need to accelerate the fuel. And also as there is no physical contact with the track, friction can be almost zero.

First, there's the idea of some researchers for a long MagLev track which accelerates a spaceship inside an evacuated track up the side of a mountain, continuously until it reaches orbital velocities when it leaves the tube. They think this could cost $20 billion to build and it would cost about $50 per kilogram to get cargo into orbit, and the project would take about ten years to complete. For details see Maglev track could launch spacecraft into orbit.

That's for cargo.

You could send passengers too, but would need a longer railway line, and slower accelerations, would take longer to build and cost more.

Maglev track could launch spacecraft into orbit.
This track is magnetically elevated

Then more exotic, is the idea of a kind of "moving walkway" Maglev track, that elevates into the sky under centrifugal force". There are many ideas like this, but this is one of the simplest and most practical of them.

The loop continually moves around like a moving walk way from one end station to the other and back again. The loop is elevated away from the Earth by the centrifugal effect of the moving walkway. This centrifugal effect raises the centre portion of the track to about 80 km. Then, much as before, the vehicles accelerate along the track until they reach orbital velocity, and release themselves from the track to launch into orbit, See Launch Loop (wikipedia)

A surprising thing about these dynamic structures held up purely by kinetic energy of rapidly moving liquid or particles - there is so much energy in the system, and so little loss, that if you stop supplying energy, they lose it only gradually. It's rather like energy stored in a flywheel or a gyroscope. Stop supplying energy and the flywheel keeps spinning; it doesn't just stop instantly.

They deserve close attention, and are not as way out and crazy as you might think when you first encounter them.

For other ideas like this, see the Dynamic Structures section in Wikipedia.

This is a section from my: Projects To Get To Space As Easily As We Cross Oceans - A Billion Flights A Year Perhaps - Will We Be Ready?