If that were true, Burt Rutan's SpaceShipOne could easily go to orbit. The higher you are, the lesser atmospheric drag there is, but Earth's gravity well is still very much present (diminishing gradually in accordance to Newton/Einstein long after air drag has fallen essentially to zero).

Could you provide me with a reference? I'd like to look it up.

I'm fully aware of Jules Verne's "Moon gun", but this concept could never work for humans due excessive acceleration. Maglev approach is the only one that I am aware of (other than rockets) that can provide a kind of "long-distance" acceleration to orbital speed tolerable by humans. Are there any other approaches I am not aware of?

Making the launch system more efficient is best done by leaving as much of it as possible on Earth, and only carry to space what's going to be used in space.

I fully agree with that. The proposed concept will require some heat shielding (hopefully, reusable on reentry), but essentially all the mass that you eject is usable in orbit (propulsion system is left back on Earth), unlike current systems that have 90-something % of their mass spent on fuel, leaving very little "usable" mass.

If you're in the business of hugely expensive, why not scrap the whole super-fast airlock and put the exit of the launch tube far enough from Earths surface that the density of the atmosphere isn't a problem anymore?

You cannot structurally put the exit of the tunnel high enough to completely avoid the atmosphere. If you could - why not just build a space elevator or even space "tower" or "needle"? For the same reason, you cannot put the tunnel in vertical position because it would be too short for comfortable acceleration, not to mention hugely more difficult to build (compared to what is already an incredibly difficult project).

Of course, the higher you are the lesser problem you have (less friction, lesser "airlock" tolerances). Running the end of the tunnel up the (very high) mountain slope comes to mind.

The reason I made this post is to see if there is anything obvious that could stop this concept from being implemented in principle. So, if anyone has more criticisms - keep them coming!

Ideal human delivery-to-orbit system:

• A tunnel, probably around 2000 km long, without any air in it, lined with magnetic levitation tracks.
• The human "cargo" is placed in what is essentially a maglev "train" and accelerates at relatively comfortable G to orbital speed (+ whatever extra is necessary to punch through the atmosphere).
• Near its end, the tunnel curves upwards and has a kind of super-fast airlock mechanism to let the "train" transition between vacuum and the atmosphere.

This would be hugely expensive to build, of course, but I have a strong feeling its capital cost would still be less then, say, annual US wasteful spending related to healthcare. Operational costs, one the other hand, would probably be just a tiny fraction of today's chemical rocket based approach.

"Get to low-Earth orbit and you're halfway to anywhere in the Solar system" - Robert Heinlein

Actually that's how we colonized Earth. Majority of today's humans are descendants of pioneers!

The development of teamwork, communication, logical thinking, usage of tools etc... is a direct consequence of evolutionary pressures - without all these tools of survival, we would not have become an evolutionary success we are today.

The "complex machines" are inevitable extension of this survival strategy.

• First believe.
• Then think.

Science:

• First think.
• Then believe.

...hence the fundamental incompatibility between the two.

Valid points, if we organize extra-Terrestrial hydrocarbon extraction operation in the same way as Apollo.

However, setting a factory that would produce rockets on site (on the given moon) and fill them with fuel available on site would change the dynamics of the problem significantly. We don't need anything sophisticated - just "point and shoot" rocket that can lift off the moon and make minimal corrections so it hits the Earth. Basically, you would have a huge financial hit at the start, but the more is produced on site, the less needs to be (expensively) carried from Earth and more economical this scheme becomes.

All of this is extremely far fetched, or course, but I don't see a reason why it shouldn't technically work by the time hydrocarbons on Earth become scarce. Whether we should try it at all (instead of developing alternative energy sources) is another matter entirely.

One more reason to look at developing technology and, perhaps, biology for self-sustained survival outside of Earth...