The space elevator gets a lot of play, nowadays. But it'll never really work. It has too many problems and relies a lot on technology that doesn't yet exist.
But the goal of inexpensive space is achievable.
How about this.
Think of electric subway tracks, or those electric toy cars and trains that use the same technology that get bought for good boys around this time every year.
Put the track down, as straight as possible for 50 to 100 miles in the least populated area, closest to the equator. The tracks aren't anything fancy like with maglev, and they don't even have to be as high-quality as those used for subways. They can actually be very cheap and flimsy as they will barely have to support the weight of a car.
The 'spaceship' will of course have to have wings, but none of its weight will ever rest on the tracks, so the miles and miles of tracks will be insanely cheap to build. Much closer to the toys than subways.
Now, imagine those toy racecar tracks again. Tie one end of a string to one of those cars and the other end to a paper airplane. With enough practice, you could get the plane to fly too.
That's close to what I propose, but not quite. There's still some rather obvious math problems if we stopped right here. The tracks that way would be incredibly expensive again, the car would have to be more powerful than a hundred trains, and the math goes off the rails soon after that.
No, what you do instead is flip the script. Instead of the car pulling the plane, the plane pulls the car along the tracks this time. This way, the 'car' only has to be big enough to stay on the tracks and conduct all that electrical power up the tether to the massive electric engines on the plane.
The length of the tether will allow the plane to fly straight while the 'car' zigzags along the terrain below until both reach escape velocity. At that point, the plane breaks the tether then goes into a climb. Its own momentum carries it most, or all of the way out of the atmosphere. Like the space shuttle, it would retain a small tank for maneuvering and to carry it into higher orbits, but all of the bulk of the solid rocket boosters and external tank is now gone. Replaced by an electric engine and a dozen powerplants connected through the grid.
You could even go 'SpaceX' style by leaving the atmospheric engines behind in a mother ship at the edge of space as a tiny rocket takes over from there.
We already have a lot of electrostatic engines that work well in the dense lower atmosphere. I think Dyson has built a fan based on this principle, and I know the Ionic Breeze is built around it. Using electricity to do all the heavy lifting will reduce the size and weight of the spacecraft considerably. It should use around a tenth the energy this way, per pound of delivered payload. That's a considerable savings.
The long track will allow for lower Gs and passengers instead of just satellites to be launched.
Of course, flying a hypersonic spacecraft this close to the ground for nearly a hundred miles has its own problems. Wind shears could be disastrous, the sound would be deafening for tens of miles in every direction, and it couldn't be piloted by human reaction times. Computers would have to control it all. But Google will probably have an app for that long before any of the track gets built : )
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