It has long been known that the chemical rocket is horribly inefficient in injecting mass into LEO. How inefficient? It costs $20,000+ per pound to put that pound into LEO with the shuttle. The actual energy cost(mv^2/2 + mgh)of that pound 100 miles up and moving at 5 mps is 4 KWH. At 10 cents/KWH that's 40 cents for 16 oz, a postage stamp to send a 1 oz letter costs 39 cents....Thus we have this space elevator concept : a satellite in geo-orbit with a 22,300 mile long elevator cable to grade, so as to elevator-lift mass to orbit. Several problems therein : icing/water vapor condensing on cable in troposphere = lightning path, red sprites in stratosphere, reactive O and N ions in LEO plasma-degrading it, orbiting space junk, possible interaction with Van Allen belts and magnetosphere; but most deadly : shorting out the earth-ionosphere capacitor of 400,000 V and 1800 A natural flow. That gets rid of electro-potential gradient(50V/m)and drastically changes the entire earth's weather.....20 years ago a small slice of the aerospace industry evolved the EMSL(ElectroMagnetic Space Launch)concept(s) during the SDI/star wars salad days: shooting projectiles into LEO with advanced EM cannons. At a 10% system efficiency that's $4/#, about the same as postage rates. The quenched superconductor rings-cannon was probably the best idea to come out of the study. Why wasn't NASA interested? Vested interests : $20,000 to do $4 worth of real work is one hellava mark-up, yes?