[RedDevil]

Originally Posted by elhigh

A Mach 2 Hyperloop on Earth could be used as a launch system. There are a few things to deal with though: anything coming out of the end is going to make one hell of a *pop* so you don't want it near populated areas. And upon emergence from the tube it'll suddenly encounter all of the aerodynamic forces that the vacuum tube has isolated it from, so that's bound to be pretty bumpy. It would probably be best to reserve that kind of service for bulk goods like fuel and other consumables. Even then its utility for space industry would be gigantic.

Another thing to try would be to run that Hyperloop right up the side of Mt. Kenya. Conveniently, Mt. Kenya sits almost on top of the equator - the best spot for launches if you'd like to make the most of the planet's own rotation to make launches easier. Adding an affordable, fast turnaround space launch facility to the heart of Africa would do wonders for economies all around it, and of the various countries in that part of Africa, Kenya is a little less chaotic than some of its neighbors.

And Mt. Kenya is over 17,000 feet high, giving you a convenient three mile head start on getting out of the atmosphere when you do come out of the tube, in addition to there being no people to complain about the noise.

Yes, it's a national park. I'm daydreaming at this point.

Moon-based launch rails, AKA mass drivers, have been discussed at length. Once we have a stable base on the moon to build stuff, we'll be able to send packages of raw material pretty much anywhere we want on the cheap. Endless solar power and no existing ecosystem? Build what you want.

One important caveat: those packages might not have braking. If you don't mind meteoric impacts (for instance, creating a surface mine of lunar-sourced aluminum ore in a conveniently uninhabited place on Mars) then the costs, once it's up and running, are pretty cheap.

As to using it for launching manned missions, well. It'll pull high G's for launching bulk goods, but if you want to get an interplanetarily useful launch velocity for humans it has to be dozens, even hundreds of kilometers long. And even then, it'll be a pretty hard push.

Thinking along the same lines

The mountain launch pipe cannot be vacuum, but we could superheat it and blow a lot of steam through.
That would create a hypersonic jet stream through which the capsule could be launced relatively easily; maybe the steam could actually double as propellant.
A tiny hydrogen/oxygen rocket could create a small amount of boost by itself and loads of superheated steam for additional pressure against the capsule in the launch pipe.
It would be a rocket powered self propelling steam cannon bullet. Far more efficient than a traditional launch system.

Best launch point imho would be Mount Chimborazo, a 6310 meter high dead volcano in Equador, just a hundred miles south of the equator; the top of the mountain is the point furthest removed from the center of the earth.
Mount Everest is higher compared to sea level, but as the earth flattens out because of its own rotation, the added circumference at the equator makes Chimborazo the winner.
As it is 0.1 % further away from the center of the earth than sea level it reduces the power needed for the launch ever so slightly, but the lower air resistance by taking off at altitude is more important.

A mass driver system could not only launch stuff, it could also brake goods coming in - but it would require great precision and a safety bailout system (side rockets?) if the lineup gets botched. The driver could best be situated horizontally over the surface so it would indeed require but a small correction to miss it and not crash.

To send stuff back to earth: I think moon rock may be great heat shield material. Weight is no problem and it is single use, no deposit. Just build the mass driver launcher so that it aims directly at earth - the moon keeps the same side towards earth all the time - and it would not need rocket fuel at all.

The human body can endure large G forces when it is floating in water. As it weighs the same as water it could endure almost limitless G forces - except for air and gases in the lungs and bowels
Rather than building swimming pools aboard spacecraft there could be hard shelled G force suits lined with soft watery gel pads. Like a body shaped tank with just an inch of play all round.
If one can endure 10 G for 23 seconds you'd be at the escape speed for the moon; 2300 meter per second. That would 'just' need a 13.2 kilometer or 8.3 mile launch track.