The study was conducted to determine if the USGS process for conducting mineral resource assessments on Earth can be applied to asteroids.
Asteroids are metallic, rocky bodies without atmospheres that orbit the Sun but are too small to be classified as planets. Known as "minor planets," tens of thousands of asteroids congregate in the so-called main asteroid belt; a vast, doughnut-shaped ring located between the orbits of Mars and Jupiter from approximately 2 to 4 AU (186 million to 370 million miles/300 million to 600 million kilometers). Asteroids are thought to be primordial material prevented by Jupiter's strong gravity from accreting into a planet-sized body when the Solar System was born 4.6 billion years ago.
Near-Earth asteroids (NEAs) have orbits that bring them within 1.3 AU (121 million miles/195 million kilometers) of the Sun. It is believed that most NEAs are fragments jarred from the main belt by a combination of asteroid collisions and the gravitational influence of Jupiter. Since 1995 the number of identified NEAs with estimated size less than 1 km has risen from ~150 to over 2300 and greater than 1 km has risen from ~200 to over 700.
Asteroids can be considered as potential sources of commodities in the same sense that a terrestrial geological terrain may have mineral potential. Platinum and other rare metals have attracted attention when asteroid mining is considered. This feasibility study focused on two practical resources to test the workflow: water and Native metal (iron-nickel alloy).
We have successfully demonstrated that the USGS resource assessment methods can be applied to asteroids. Water and iron resources were used to test the workflow, resulting in identifcation of adjustments needed to conduct full assessments beyond Earth. This was a feasibility study and was not an assessment of NEA resources. Our report discusses assumptions made and new areas of research needed to conduct a proper assessment of resources in NEAs.
Keszthelyi, L., Hagerty, J., Bowers, A., Ellefsen, K., Ridley, I., King, T., Trilling, D., Moskovitz, N., and Grundy, W., 2017, Feasibility study for the quantitative assessment of mineral resources in asteroids: U.S. Geological Survey Open-File Report 2017–1041, 28 p., https://doi.org/10.3133/ofr20171041.
Keszthelyi, L., Hagerty, J., King, T., Ridley, I., Trilling, d., Mommert, M., Moskovitz, N., and Grundy, W., 2016, Initiating a USGS assessment of asteroid mineral resources: 47th Lunar and Planetary Science Conference, March 21-25, 20216, The Woodslands, TX, 2 p. View Keszthelyi 2016 abstract. [PDF file, 138 KB]
W. Ian Ridley
Central Mineral and Environmental Resources Science Center