While asteroids and comets pose a potential threat, they also present a long-term interplanetary opportunity. Scientists project that we will have depleted many of the Earth’s natural resources by the middle of the 21st century. The solution to resource shortages may be the mining of asteroids. Based on meteorite samples, some Earth-approaching asteroids must contain not only pure nickel-iron alloys, but also ores of economically important platinum-group metals. These asteroids could be mined in space using the freely available solar energy that constantly streams through space. Masses of metal worth many billions of dollars — enough to satisfy Earth's need of some metals for decades — should be obtainable from individual kilometer-scale and smaller asteroids. Another resource on asteroids is a high abudenace of "rare Earth" elements, which are expensive and heavily used in the semiconductor and electronics industries. Studies are already underway to examine the feasibility of flying to Earth-approaching asteroids for economic and scientific exploration. In terms of energy expenditure, some of them are actually easier to reach than the Moon!
If asteroid resources could be harvested and developed in space, then mining, processing and the consequent industrial pollution would decline on Earth. Instead of a purely defensive response to the asteroid threat, we could invest in a positive program to expand our knowledge about asteroids. The ability to reach asteroids and deflect them from one orbit to another would emerge as a by-product of such a program, and would also solve the problem of the asteroid threat. At the same time, such a program would help to resolve Earth's environmental problems.
OSIRIS-Rex artist rendition. Click here for original source URL.
Close up of Comet Hartley 2. This image was captured by NASA's EPOXI mission between Nov. 3 and 4, 2010, during the spacecraft's flyby of comet Hartley 2. It was captured using the spacecraft's Medium-Resolution Instrument. Click here for original source URL.
A computer rendering of?Hayabusa?above Itokawa's surface. Click here for original source URL.
Particle captured in aerogel from Comet Wild 2 in the Stardust mission. Click here for original source URL.
Artist's conception of the NEAR Shoe n maker spacecraft. Click here for original source URL.