Mining metals from asteroids seems a bonkers idea. But could it work?
CAN reality trump art? That was the question hovering over the launch on April 24th, at the Museum of Flight in Seattle, of a plan by a firm called Planetary Resources to mine metals from asteroids and bring them back to Earth.
4月24日，行星资源公司（Planetary Resources）在西雅图的航天博物馆（Museum of Flight）启动了一项计划——在小行星上采矿并将矿物带回地球。对这项计划，人们一直都在疑惑：现实能否战胜艺术？
It sounds like the plot of a film by James Cameron—and, appropriately, Mr Cameron is indeed one of the company’s backers. The team behind the firm, however, claim they are not joking. The company’s founders are Peter Diamandis, instigator of the X Prize, awarded in 2004 to Paul Allen and Burt Rutan for the first private space flight, and Eric Anderson, another of whose companies, Space Adventures, has already shot seven tourists into orbit. Larry Page and Eric Schmidt, respectively the chief executive and the chairman of Google, are also involved. So, too, is Charles Symonyi, the engineer who oversaw the creation of Microsoft’s Office software (and who has been into space twice courtesy of Mr Anderson’s firm). With a cast-list like that, it is at least polite to take them seriously.
这听着就像詹姆斯?卡梅隆的电影中的情节——恰好，詹姆斯?卡梅隆实际上就是这家公司的赞助人之一。但是公司背后的团队宣称小行星采矿这事可不是在开玩笑。行星资源公司的创始人是X奖（2004年Paul Alle和Burt Rutan因首次实现私人太空飞行而获颁此奖）发起者Peter Diamandis和拥有太空探险公司（Space Adventures）（已将七位游客送上太空）的Eric Anderson。GOOGLE的总经理Larry Page和董事长 Eric Schmidt也参与其中，曾负责监督开发微软办公软件的工程师Charles Symonyi同样是其中一分子（通过Eric Anderson的公司，他也上过太空两次）。阵容如此强大，出于礼貌至少也该重视这个想法。
As pies in the sky go, some asteroids do look pretty tasty. A lot are unconsolidated piles of rubble left over from the beginning of the solar system. Many, though, are pieces of small planets that bashed into each other over the past few billion years. These, in particular, will be high on Planetary Resources’ shopping list because the planet-forming processes of mineral-melting and subsequent stratification into core, mantle and crust will have sorted their contents in ways that can concentrate valuable materials into exploitable ores. On Earth, for example, platinum and its allied elements, though rare at the surface, are reckoned more common in the planet’s metal-rich core. The same was probably true of the planets shattered to make asteroids. Indeed, the discovery of a layer of iridium-rich rock (iridium being one of platinum’s relatives) was the first sign geologists found of the asteroid impact that is believed to have killed the dinosaurs.
Most asteroids dwell between the orbits of Mars and Jupiter. But enough of them, known as near-Earth asteroids, or NEAs, come within interplanetary spitting distance of humanity for it to be worth investigating them as sources of minerals—if, of course, that can be done economically.
First catch your hare
The first thing is to locate a likely prospect. At the moment, about 9,000 NEAs are known, most of them courtesy of ground-based programmes looking for bodies that might one day hit Earth. That catalogue is a good start, but Planetary Resources plans to go further. In 2014 it intends to launch, at a cost of a few million dollars, a set of small space telescopes whose purpose will be to seek out asteroids which are easy to get to and whose orbits return them to the vicinity of Earth often enough for the accumulated spoils of a mining operation to be downloaded at frequent intervals.
That bit should not be too difficult. But the next phase will be tougher. In just over a decade, when a set of suitable targets has been identified, the firm plans to send a second wave of spacecraft out to take a closer look at what has been found. This is a significantly bigger challenge than getting a few telescopes into orbit. It is still, though, conceivable using existing technology. It is after this that the handwaving really starts.
Broadly, there are two ways to get the goodies back to Earth. The first is to attempt to mine a large NEA in its existing orbit, dropping off a payload every time it passes by. That is the reason for the search for asteroids with appropriate orbits. This approach will, however, require intelligent robots which can work by themselves for years, digging and processing the desirable material. The other way of doing things is for the company to retrieve smaller asteroids, put them into orbit around Earth or the moon, and then dissect them at its leisure. But that limits the value of the haul and risks a catastrophic impact if something goes wrong while the asteroid is being manoeuvred.
Either way, the expense involved promises to be out of this world. A recent feasibility study for the Keck Institute for Space Studies reckoned that the retrieval of a single 500-tonne asteroid to the moon would cost more than $2.5 billion. Earlier research suggested that, to have any chance of success, an asteroid-mining venture would need to be capitalised to the tune of $100 billion. Moreover, a host of new technologies will be required, including more-powerful solar panels, electric-ion engines, extraterrestrial mining equipment and robotic refineries.
不论哪种方法，所需费用都一定是天价。最近，克柯太空研究所（Keck Institute for Space Studies）进行的一项可行性分析认为，将一颗重量为500公吨的小行星移到月球附近所耗资金将超过二十五亿美元。较早前的研究指出，必须投资一千亿美元才有可能实现小行星采矿。而且，还需要大量新技术，包括功率更大的太阳能电池板、电子离子引擎、太空采矿设备和自动冶炼厂。
All of which can, no doubt, be done if enough money and ingenuity are applied to the project. But the real doubt over this sort of enterprise is not the supply, but the demand. Platinum, iridium and the rest are expensive precisely because they are rare. Make them common, by digging them out of the heart of a shattered planet, and they will become cheap. The most important members of the team, then, may not be the entrepreneurs and venture capitalists who put up the drive and the money, nor the engineers who build the hardware that makes it all possible, but the economists who try to work out the effect on the price of platinum when a mountain of the stuff arrives from outer space.