The mineral value of near-earth asteroids is prompting some companies to begin paying attention to these potentially lucrative targets.

A 200-m-diameter metallic asteroid, for instance, could contain as much as $25-billion worth of platinum-group metals (PGMs) alone and in greater concentrations than is currently commercially mined on earth. Many are over 1 km in diameter and also contain gold, copper, nickel, iron, water and volatiles.

In addition, some of these near-earth objects may pose a collision risk and mining could reduce that risk while simultaneously generating commercial returns, says advocacy group South African Space Resources Association founder and consulting engineer-ing firm Hatch mining engineer Michael Neale.

Technically, the second joint meeting between the Planetary and Terrestrial Mining Sciences Symposium VI and the Space Resources Roundtable XI concluded that in situ space resource utilisation (ISRU) required advances in autonomous robots.

Further, robotic precursors and robotic probes (or probots) are also needed to pave the way for humans. For example, lunar mining technology company Shackleton Energy intends to use robots for lunar probing and infrastructure construction. Once a base is ready, manned missions (supplemented with robots) will be used to the mine water ice, which can be processed into rocket fuel.

Once refuelling is possible on the lunar surface, the rocket needed for a manned lunar mission only needs to be three-quarters the size of the Apollo-series mission rockets. Orbital refuelling infrastructure around earth and the moon (with fuel sourced from the moon) could further reduce the rocket size to 12%.

In a challenge to engineering students, US space agency National Aeronautics and Space Administration’s (Nasa’s) Lunabotics competition requires the design and building of mining robots for use on the moon, Neale reports.

Meanwhile, search engine company Google is sponsoring the Lunar X-prize, a $20-mil- lion competition for privately funded teams to launch and operate a rover on the moon. The competition has attracted entries from 33 teams. Together, the teams have spent more than the prize money, but this is over- shadowed by the fact that some of the com- panies are offering launches to the moon for $1.8-million per kilogram lifted and have garnered interest for this service from both private and public organisations.

The Pacific International Space Center for Exploration Systems (Pisces), on Hawaii Island, hosts international multiagency field tests, which has served to demonstrate and verify ISRU technologies and simulate remote operations of potential outposts on the moon, as well as Mars.

These tests can also simulate the communi-cation delay between earth and the moon or Mars, says Pisces researcher operations manager Christian Anderson. Pisces recently agreed to also field-test various Google Lunar X-Prize teams’ rovers and landers.

The robotic rovers operating at the Pisces test site can be operated remotely through the Internet and schools from South Africa, Chile and Canada have already participated in the study designed to simulate the logistics of lunar and Martian exploration, as well as stimulate interest among youths in science, astronomy and engineering.

But, besides the technical challenges sur-rounding such exploitation, there are also some more mundane legal and economic concerns.

A specific challenge hampering long-term planning is the current low security of tenure, as well as a lack of legal precedent on mining such targets, says Neale.

However, there are also concerns that the exploitation of such resources could destabilise markets by potentially deflating prices and upsetting resource-linked economies.

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