[meteorite-list] Astronomers Identify 12 Candidates for Asteroid Mining

[Ron Baalke]

http://www.extremetech.com/extreme/163749-astronomers-identify-12-asteroids-we-could-easily-mine-for-valuable-resources

Astronomers identify 12 asteroids we could easily mine for valuable resources
By Ryan Whitwam 
Extreme Tech
August 12, 2013

Science fiction authors and futurists have been musing on the possibility 
of mining asteroids for decades, but last year a company called Planetary 
Resources declared its intention to actually do it. That got people thinking 
about whether or not humanity has really reached the point where asteroid 
mining could become a reality. A group of astronomers at the University 
of Strathclyde in the UK have replied with an emphatic, "yes.' They have 
identified 12 near-Earth asteroids that could be easily retrieved and 
mined with current rocket technology.

It's believed that asteroids could contain large deposits of industrial 
and precious metals. An unremarkable one-kilometer asteroid could contain 
upwards of two billion tons of iron-nickel ore, which is three times the 
global yield on Earth. Then there is the likely presence of gold, platinum, 
and other rare substances. Planetary Resources claims a 30-meter object 
of the right composition could contain $25 to $50 billion in platinum.

These numbers spurred the University of Strathclyde team, led by Garcia 
Yarnoz, to pour over the astronomical data on near-Earth objects to see 
if any of them could actually be snared. To their surprise, they found 
12 small asteroids that pass close enough to Earth that they could be 
corralled into the L1 or L2 Lagrangian points for mining operations. The 
researchers dubbed these asteroids Easily Retrievable Objects (EROs).

Lagrangian points are regions of space where the gravity of the Earth 
and another celestial body balance out. If you place something in a Lagrangian 
point, it stays put. That's exactly what you want if you're going to start 
drilling into an asteroid. The L1 and L2 Lagrangian points are where the 
gravity of Earth and the sun are at a draw. They are about 1 million miles 
from Earth, or about four times the distance to the moon.

The 12 candidate asteroids are in orbits that take them near the L1 or 
L2 Lagrangian points, so they would need only a small push to get them 
to the right spot. Yarnoz and his team estimate that changing the velocity 
of these objects by less than 500 meters per second would be sufficient 
- some would take substantially less effort. One ERO called 2006 RH120 
could be captured by changing its velocity by only 58 meters per second. 
This could be completed as early as 2026.

One of the important criteria in filtering the database of 9,000 near-Earth 
objects down to the 12 mineable asteroids was size - we simply don't have 
the technology to safely nudge a large asteroid into a Lagrangian point. 
There will be no mega-sized mining platforms spanning a one-kilometer 
asteroid in the near future. Most of the EROs identified by the study 
are in the two to 20 meter range, but that's still large enough to contain 
substantial resources.

These 12 objects are probably a small fraction of EROs floating around 
near Earth. We know where many more of the big space rocks are because 
they're much easier to see, but there might be a wealth of resource-rich 
small asteroids near the Lagrangian points ripe for the picking.

Research paper: arXiv:1304.5082 - "Easily Retrievable Objects among the 
NEO Population" (Paywall)
http://arxiv.org/abs/1304.5082