Yep - it's the costs of getting off the ground and re-entry that make space travel prohibitively expensive at the moment. A couple of ideas that have been thrown around are carbon-fiber nanotube-based elevators to a geosynchronous station, and a rotating station that alternately elongates and contracts to deliver items to and from orbit.

The best applications of commercial "space" flight will be low-earth-orbital sightseeing (or maybe commercial research) and suborbital point-to-point hops. And then the airlines will need to solve the "space suit problem." Which is: what are the passengers going to think when a flight officer tromps through the passenger cabin on the way to a lavatory? Or will the flight officers stay in an expanded cockpit--expanded to about the size of the old Space Shuttle cabins, maybe?

Now maybe people think the novelty of space or suborbital flight will make those passenger take anything. But novelty wears off. And ask yourselves why the Concorde doesn't fly anymore.

I can name exactly one resource anyone is likely to find on any asteroid--and preferably on comets: heavy water. I think you'll find that cometary or asteroidal ice will have, on average, twice the concentration of heavy waters (HDO, D2O) of the oceans of Earth. That might be important in the development of fusion power.

Building a fleet of ships to go out and get it--now that's something else again. With a skyhook, maybe you can cut the lifting costs down. If you find enough iron and heavier metals on the moon, maybe you can build your fleet in space, using materials taken from space. A lot of maybes.

But don't count on finding heavy metals in the asteroids. I think you'll find they contain nothing but plain ordinary rock, mud, and ice. The ice might be worth getting--just how much worth, depends on the amount of ice and the concentration of deuterium.

Agreed, the task is enormous at present, like sailing 3 ships off the edge of the world was to 15th century technology. We MUST make the investment and overcome the inertia until the production of energy, raw materials, and manufactured tools are achieved above the gravity well.
This may be the only remaining hope for individual liberty and free markets for terran life.

BTW, did you see the new department NASA created? the Planetary Defense Coordination Office.
http://www.geek.com/science/nasa-crea...

Why am I not relieved?

Perhaps we can find some invaluable dilithium crystals! ;)

The professor in the office next to mine has had contracts with NASA and some of its subcontractors for lunar mining and currently the mining of Mars. The amount of equipment, and the energy and mass required to launch both fuel and equipment, are serious limitations on extraterrestrial mining.

Jeff Bezos' new space flight company, Blue Origin, is off to quite a nice start, according to a couple of my former students.

So many people like to argue that we need the government to fund space travel because without the government, it wouldn't happen! Well, this isn't reality because it's happening now! Private companies are flying to space and in the very near future we will have commercial flights to outer space. Rocket launches by these private companies are actually tens of millions of dollars cheaper compared to a NASA launch! And right now, private companies are planning on mining asteroids to extract rare earth metals. This is the beauty of capitalism at work and it doesn't cost the tax payers a dime.