I wrote:
solar system to prospect for precious metals. 300 GW of Ne-powered
rockets is . . .
Oops. Meant Nd-powered. As in Nd-magnet electric rocket, an Ion or
MPD or what-have-you.
Regarding the availability of neodymium (Nd), see the USGS page on rare earths:
http://minerals.usgs.gov/minerals/pubs/commodity/rare_earths/
You should see how much the Chinese are mining this stuff! See:
http://pubs.usgs.gov/fs/2002/fs087-02/
Quote:
"The rare earth elements (REE) form the largest chemically coherent
group in the periodic table. Though generally unfamiliar, the REE are
essential for many hundreds of applications. The versatility and
specificity of the REE has given them a level of technological,
environmental, and economic importance considerably greater than
might be expected from their relative obscurity. The United States
once was largely self-sufficient in these critical materials, but
over the past decade has become dependent upon imports (fig. 1). In
1999 and 2000, more than 90% of REE required by U.S. industry came
from deposits in China."
If the U.S. ever goes to war with China, it will be over in a week.
They will just stop selling us just about every high-tech product and
material we need, and wait for us to fold up. I doubt we could set up
factories to make computer screens or cell phones in time to affect
the outcome of a modern war, and without such things, you lose. I do
not think it is wise to become so dependent on what remains, after
all, a communist dictatorship. The USGS is cognizant of this. It says
our dependency on China raises "important issues of REE supply for
the United States" including:
"(2) United States dependence on imports from China comes at a time
when REE have become increasingly important in defense applications,
including jet fighter engines and other aircraft components, missile
guidance systems, electronic countermeasures, underwater mine
detection, antimissile defense, range finding, and space-based
satellite power and communication systems."
Fig. 4 in this paper is an interesting depiction of element abundance
in the earth's upper continental crust. The rare earths are not so
rare compared to Au, Pt and Pd. Ir seems to be the rarest of all. Of
course, just because an element is common that does not necessarily
make it cheap or easy to recover.
- Jed
