The development of civilisations like ours into spacefaring, multi-planet entities requires significant raw materials to construct vehicles and habitats. Interplanetary debris, including asteroids and comets, may provide such a source of raw materials. In this article we present the hypothesis that extraterrestrial intelligences (ETIs) engaged in asteroid mining may be detectable from Earth. Considering the detected disc of debris around Vega as a template, we explore the observational signatures of targeted asteroid mining (TAM), such as unexplained deficits in chemical species, changes in the size distribution of debris and other thermal signatures which may be detectable in the spectral energy distribution (SED) of a debris disc. We find that individual observational signatures of asteroid mining can be explained by natural phenomena, and as such they cannot provide conclusive detections of ETIs. But, it may be the case that several signatures appearing in the same system will prove harder to model without extraterrestrial involvement. Therefore signatures of TAM are not detections of ETI in their own right, but as part of "piggy-back" studies carried out in tandem with conventional debris disc research, they could provide a means of identifying unusual candidate systems for further study using other SETI techniques.
Some pretty interesting speculation on the industrial motivations, risks, and capital factors in the asteroid-mining business, in addition to the discussion of SETI search parameters.
Humans have not begun asteroid mining primarily for reasons of political economy. While the resources still exist in affordable quantities on Earth, governments lack a good short-term economic case to attempt dangerous missions at high cost to bring back what would initially be modest quantities of raw materials. As Hickman (1999) observes, asteroid miners should not expect immediate investment from private investors either. While the potential return from successful, properly matured asteroid mining missions is very large, the level of capital required up front for any large-scale space project is also very large - Schmitt (1997) optimistically estimates a sum of around $15bn for general commercial space enterprise (assuming fusion technologies based on lunar 3 He become profitable, and not considering the problems presented by the current financial landscape).
Further to this, the maturation time period (before profits can be generated) is too long, i.e. greater than 5 years. Other large-scale space projects (such as Martian colonisation) are equally unappealing for investors looking for returns on their investments within a decade - Hickman (1999) gives a simplified example which shows that if Mars can be terraformed in less than a thousand years, even a modest rate of interest on an initial loan requires Martian real estate to be extremely expensive. While there might not be a good short-term economic case for governments to fund TAM missions, there are long-term economic and political motivations (see Gerlach 2005 for a thorough review). If the initial high capital barrier can be overcome, and profits can be generated, then manufacturing future tech- nologies will become much cheaper as the precious metals become less precious. The expertise gained by designing and undertaking TAM missions can then be brought to bear on other challenges in space explo- ration.
Relevant: possible beginnings of asteroid-mining venture capitalism:
www.reddit.com/r/technology/comments/sgetc/mystery_company_backed_by_james_cameron_and/
http://www.kurzweilai.net/page-cameron-simonyi-perot-to-back-launch-of-extraterrestrial-mining-company
