Great topic...
yeah, the bitch is always going to be getting mass into LEO. That has to be done in an environmentally sound manner, and that pretty much restricts it to hydroxygen chemical rockets right now. (OK, maybe methane-oxygen also) (I am discounting speculative things like the laser mirror drive - that thing is bound to spit out great clouds of NOXious byproducts.) Even if you write off the cost of all the launch hardware (vehicles, support facilities, bored controllers manning workstations and eating donuts and swilling Sprite), getting a kilo from Earth's surface into LEO will cost you at least the delivered mkt price of over a hundred kilos of LH2 and LOX.
No matter how you slice'm apples, it comes up big $$$$.
...Once you ARE in LEO, all fat&happy... transfer to just about anywhere can be dead cheap. Low thrust, high-Isp drives (ion, magnetoplasma, ?other stuff) work great once you're above atmosphere. Sails might even be made to work after a few more decades of material engineering ... very low thrust but infinite Isp. No reaction mass a-tall, the rocket scientist's fondest wish! (not counting sharing a Soyuz lifeboat with Cindy Crawford, lol)
cheers LRR |
