Friday, September 22, 2006

White Gold and Blue Diamonds

The founder and CTO of SpaceDev calls ice "white gold" because of the potential for asteroidal ice to be the lifeblood (and rocket fuel) of operations in the solar system in the future. A strong case for the use of water in space is made in the awesome book "Mining the Sky" by John S. Lewis.

The most likely and nearest-term scenario for use of water in space is the "gas station" scenario. Fuel depots would be placed in low Earth orbit (LEO) to refuel vehicles needing to reposition an orbit, or to leave LEO altogether. The idea of mining water from near-Earth asteroids is attractive because of the prohibitive cost of launching fuel to be placed in these depots. To use water as a fuel, it could be electrolyzed (split it into hydrogen and oxygen), the hydrogen could be heated, or the hydrogen and oxygen could be combusted, or the water could be heated directly for steam power. There's a great overview of the use of water as fuel in space here.

Elon Musk, the founder and CTO of SpaceX was quoted as not seeing much in "space mining". In a speech given at the 9th Annual International Mars Society Conference, he stated “I don’t believe in the mining of stuff in space. The transportation costs are so horrendously high that I don’t think there’s anything… if there were packages of purified crack cocaine in orbit right now, I’m not sure it would be financially viable to go and retrieve them." I agree, right now -- 2006 -- mining resources in space and bringing them to Earth would probably have a negative return on investment. But regarding his point of general disbelief about the idea of "space mining", I beg to differ. And I don't mean to discount Mr. Musk's genius, it's just that history is not on his side regarding predictive statements (in the negative) concerning technological developments.

Anyway, if water is white gold I would call He-3 blue diamonds. Elemental gold is valued around $20K per kilogram. If He-3 fusion were to become a reality, the value of He-3 would be something like $6 Million per kg. I admit to being ignorant about comparing this to the street price of crack cocaine, but I think this is a few orders of magnitude better.

Harrison Schmitt, last man to step foot on the moon, outlines the development of He-3 fusion resources from the Moon (for return back to the Earth) in his book Return to the Moon: Exploration, Enterprise, and Energy in the Human Settlement of Space .

I've only skimmed through the book, but if you aren't up for reading it, there was recently a fascinating interview with Dr. Schmitt on the Space Show.

But here's the scenario that to me is even more cool than the Moon scenario. In "Mining the Sky" the case is made for extraction of a rare form of Helium (He-3) from our second favorite blue planet, Uranus (the vanquished God and 7th planet from the Sun). The book provides a scenario where an unmanned rocket takes an 8 to 9 year journey to Uranus (which has an abundant supply of Helium and Hydrogen) and immediately after entering the atmosphere, deploys a hot air balloon (a non-explosive Hindenburg!) and begins mining atmospheric He-3 and hydrogen (He-3 for terrestrial fusion, hydrogen for fuel for the return trip). According to the author's analysis, the payoff for the mission would be around 20,000:1, and the main technologies needed would be a nuclear thermal rocket (around since the 60's), ablative shielding, and cold storage and processing technologies. The only technology not available today is a He-3 fusion device! But I believe Dr. Schmitt makes a very strong case for the likelihood of He-3 fusion. The future will tell!


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