At present time, there is not one element in the known solar system that is worth the cost, time and effort to retrieve... except the Helium 3 on the lunar surface.
Even if an asteroid was found to be 100% flawless diamond... or 100% titanium or platinum... the minerals would still would be more costly to retrieve per pound than it is worth. The asteroid Psyche is 140 miles in diameter (that's a BIG rock)... and is mostly Iron and Nickel. There may be small amounts of silver or other ore. Even if it were 100% silver, it would not be worth the cost, time and effort to mine and return it to Earth.
At present time, there is not one element in the known solar system that is worth the cost, time and effort to retrieve... except the Helium 3 on the lunar surface.
Even if an asteroid was found to be 100% flawless diamond... or 100% titanium or platinum... the minerals would still would be more costly to retrieve per pound than it is worth. The asteroid Psyche is 140 miles in diameter (that's a BIG rock)... and is mostly Iron and Nickel. There may be small amounts of silver or other ore. Even if it were 100% silver, it would not be worth the cost, time and effort to mine and return it to Earth.
you don't return it to earth, you bring it to NEO. and use it to build spacecraft in space....