Cecil, even the smartest guy on Earth should read up on the recent developments in an area before posting an article.
You said “The prize here consists of the so-called platinum-group metals, which besides platinum include osmium, iridium, palladium, ruthenium, and rhodium and are relatively abundant in some asteroids.”
Actually, no. Not to the people interested in going after the asteroids, like Planetary Resources. They are interested, because they wish to make settlement of the rest of the Solar System possible. To them, the prize is water, first, Ammonia, and other ices come second, third is Carbon and then Iron and Nickel for building stuff third, siliceous materials for glass and heat shields, …and then, the residue has Platinum group metals. Water is precious, because you can make hydrogen and Oxygen propellants from it. The Carbon can be made into graphene for composites with the plastics you can make with the first 3 things and later into graphene/diamond composites. These can be used to make spaceships headed out to the rest of the Solar System. Nickel and Iron can be used to make tankage at the EML-2 point you mentioned, or EML-1 as well, for the electrolyzed and liquified Hydrogen/Oxygen propellants early in the life of the Libration Point station. The platinum group metals can be used where catalysts are needed, or high temperature or corrosion resistance is a must.
Then, once the needs of space settlement are fulfilled, we can drop some leftover Platinum group metals down the gravity well. Till then, you would be sending them from where materials are expensive (if they are launched from Earth), to where they are, …relatively, …cheap. That’s a dead loss. No business plan that does that will succeed.
Note that, as in human spaceflight itself, these “in situ resource developments” make sense only in the context of settling the Solar System. That is what groups like SpaceX and Planetary Resources are betting on. They have no faith that NASA will do it, certainly, because Congress would not fund it.
The idea of an asteroid mass small enough to process being a problem for altering the the Earth’s orbit or spin disregards Newton’s Laws. Gravitational force has an inverse square relationship to distance. The optimum asteroid being looked for right now, for rendering by the present technological base we have, is about 7 meters across, and a carbonaceous chondrite. It would mass between 350 and 1000 tons. It is over 300,000 miles away at the EML-2 point. Thus, each ton’s effect on Earth’s orbit or rotation is 75^2, or 5,625 times less than a ton floating on Earth’s ocean. A 500,000 ton supertanker on the Earth’s ocean has 2,812,500 times the effect that optimum sized asteroid would while being rendered down. Yet, no one has any fears of throwing off the earth’s rotation, much less its orbit.
We have better things to worry about than this, …like how to get a seat on the first ship leaving a Libration Point Station, for all the rest of the Solar system.
