Thanks for that Rich. You explain it well. It's good to have some figures for the Δv of the different options. What sort of nuclear engine are you considering in your chemical vs nuclear comparison?
Ooops... I was considering a solid-core fission thermal rocket - something along the lines of NERVA or Timberwind.
Just checking... LEO is Low Earth Orbit? NEO is Near Earth Orbit?
If that's right, are these asteroids: Nearby, Orbiting Earth? Orbiting [the sun] Near Earth? Orbiting Near Earth's Orbit?
OR is NEO Near Earth Object? And would that object be: An Object Near Earth? An Object passing Near Earth?
And if the object's not always near Earth, would it be worthwile setting up mining infrastructure on it?
AND what's "injection", in this context?
I've always missed something important, haven't I?
"LEO" is "Low Earth Orbit" - the sort of orbit that things like the Shuttles and ISS operate in. "NEO" is "Near Earth Object", which means an asteroid or comet with an orbit around the Sun near that of the Earth. (There are also, of course, lots of asteroids in the main belt between the orbits of Earth and Mars, and possibly even more than that in the "Trojan" and "Greek" clusters at the stable Jupiter-Sun Lagrange points.)
I think you'd have to plan your mining infrastructure deployments and target asteroids very carefully to make it worthwhile, because the easier it is to get to an asteroid the less frequent the launch windows. This probably means that asteroid mining is going to be a multi-decade operation.
As I said, a Hohmann transfer requires two rocket burns - one at the source and one at the destination. In this context, "injection" is the first burn, that puts you on an elliptical orbit that takes you to the vicinity of your destination. If you don't make your second burn or aerocapture you will fall along the orbit to get back to the point in space from which you originated, which is unfortunate because the planet or asteroid that you left from won't be there then (it'll have moved on around its orbit). If you're prepared to use more fuel, you can get onto "free return" trajectories that will compensate for this and make your journey much safer.
Delta-v is largely unrelated to the cost of space travel; the cost of space travel is the cost of keeping people alive in a hostile setting: those cost presently run about $3 million per person day.
impossible!
I was reading John McFee's "Curve of Binding Energy" and scarring the hell out of myself, again, as my first read was in 1974. Ted Tayor the protagonist,worked on Project Orion while at Atomics International. Could you comment on how that propusion concept could impact your calculations.
Very good discussion of the physics and economics of space industry and colonization.
A similar discussion can be found in Pournelle's A Step Farther Out where he goes over the Delta-Vee calculations.
But much of the space industry theory depended on non-rocket resources, such as mass drivers on the Moon to access lunar materials...and mass drivers spilling slag off asteroids, to produce thrust and move them close to Earth. Plus the production of energy for Earth itself as a major product that would spur this development.
GE analyzed asteroid mining early in the 1960s, and focused on things like gold, platinum, iridium, palladium and other expensive and rare goods.
Nice Hohmann transfer graph. What program did you use to make it?
Rick,
This is all now a bit long in the tooth (though very clear), and I wonder if you might update it in light of LCROSS etc.
I'm specifically interested in your calculation of cost per tonne moved in your reference missions, which are calculated from LEO, with the assumption that "The cost of such fuel brought up from the surface of the Earth is dominated by the launch vehicle costs". What costs do you get if it's lifted (a bit) from a lunar pole and then dropped down the Earth's gravity well to LEO?
I'm guessing the economics all looks pretty different?
Yes, that would probably change things. It's much harder then to calculate minimum bounds for prices of missions but I suppose the costs would be dominated by the cost of extracting water on the Moon. I have no idea how to even estimate that, I'm afraid.
By the way, I recommend Wikipedia's article on Delta-v budgets, which probably has better figures than I do, and a nice diagram too.