Actually I'm also an inventor and am patenting a few things. I have been developing a concept for space travel.

The biggest obstacle to colonising space is to get enough mass into orbit, from there you can make something to get you to a near Earth asteroid and pick up more material. The problem is basically the same with the Moon, if you can get enough material into orbit from the Moon you can do the same thing.

So the thing that has killed space exploration over and over is the cost of getting enough material into orbit. If you could get enough there to build something to visit an asteroid in 10 years people would be travelling all over the solar system.

When I say material I mean it isn't so important what kind of material it is, since what it mainly needs to do is protect against radiation, hold in an atmosphere, and be heatable enough to expel as propulsion. People tend to think of expensive materials because of the cost of transport but expensive materials are not needed, even granite would do well enough.

The concept then is to get something into orbit cheaply. The system I have been working on involves either a space craft to periodically dip into the atmosphere or a low orbiting probe with a tether to drag machinery along in the upper atmosphere.

This machinery is basically a refridgerator. Air is taken in and compressed, and the CO2 and water are frozen. Some other gases may also be liquified though they are more trouble. Then the frozen blocks are made into shapes like bricks and are moved into higher orbit with a catapult or some blocks can be heated for propelling others into higher orbit. A nuclear tub would be good for this, to heat some of the CO2 or water and carry the blocks into higher orbit.

Once there the blocks are assembled into the shape of a space station, like an igloo and covered with reflective material to stop them melting. Since you have Carbon, Hydrogen (from water) and Oxygen you can make any kind of hydrocarbon (e.g. plastics) and carbohydrates. You can take along some Nitrogen for making fertiliser. You can make methane for rocket fuel like Zubrin would, or break the water up into Hydrogen and Oxygen.

A large enough chunk can be dropped onto the Moon to start a Moonbase. Another chunk can be propelled by a nuclear reactor for a trip to Mars. Such an igloo might be a few hundred meters in diameter and contain a full ecosystem. So whoever went to mars in it could just park near say Phobos for more raw materials and build a permanent colony right off.

Another could rendezvous with a Near Earth asteroid or go out to the asteroid belt. By using raw materials found they could simply keep building more crude space ships and with a reactor in each keep expanding.

The cost of this system should be low compared to most space travel as it only needs to get into low Earth orbit. Once there it can use some of the gases it collects to propel itself from losing orbit. A catapult would probably be easiest to send block up to a higher orbit so they could be assembled. As long as it can be powered enough to keep from orbital decay and have enough power to send the blocks upwards there would be little to go wrong. Rather than a reactor it would probably be powered by a higher satellite beaming power to it.

Another advantage is it would get a lot of carbon into orbit where an eventual space elevator could be built.

Imagine for example if you got a block of material that way into orbit, say 2,000 cubic meters. With that amount of material anything could be done. Say for example the probe made blocks of ice or CO2 a cubic meter in size and could do one every orbit. Each probe could send up 365 cubic meters a year and say with 3 probes working a 1,000 cubic meters a year.

In a few years there would be enough to go to an asteroid and the whole thing grows from there.