The idea of building a robotic manufacturing facility in space might have been in the realm of a Star Wars, Star Trek or other science fiction story, but like some of the technologies in those tales, reality may soon imitate art.
First off, you may recall that NASA is looking for an asteroid weighing about 500 tons that could be moved into within the moon's orbit so astronauts can examine it as early as 2021.
[MORE: The sizzling world of asteroids]
Because asteroids are loaded with minerals that are rare on Earth, near-Earth asteroids and the asteroid belt could become the mining centers for remotely operated excavators and processing machinery. In 20 years, an industry barely imagined now could be sending refined materials, rare metals and even free, clean energy to the Earth from asteroids and other bodies," according to NASA scientists in a recently published paper entitled: "Affordable, Rapid Bootstrapping of the Space Industry and Solar System Civilization."
The scientists say two fundamental developments make this prospect possible: robotics and the discovery of fundamental elements to make plastic and rubber and metals existing throughout space. Another critical technology also is coming in at just the right time: manufacturing in the form of 3D printers that can turn out individual pieces that can be assembled into ever-more-complex machinery and increasingly capable robots.
"Now that we know we can get carbon in space, the basic elements that we need for industry are all within reach," said one of the paper's authors, NASA physicist Phil Metzger said. "That was game-changing for us. The asteroid belt has a billion times more platinum than is found on Earth. There is literally a billion times the metal that is on the Earth, and all the water you could ever need. The idea is you start with resources out of Earth's gravity well in the vicinity of the Earth. But what we argued is that you can establish industry in space for a surprisingly low cost, much less than anybody previously thought."
Metzger said that when the scientists wrote this paper we were focused on the moon as a source of near-Earth resources, but near Earth asteroids work equally well and offer several additional advantages. "It takes less fuel to bring resources away from the lower gravity of an asteroid, and since the ultimate goal is to move the industry to the asteroid main belt starting with asteroids first will help develop the correct technologies," Metzger said.
A near-Earth asteroid or other nearby body presumably will contain enough material to allow a robotic system to mine the materials and refine them into usable metal or other substances. Those materials would be formed into pieces and assembled into another robot system that would itself build similar models and advance the design.
"The first generation only makes the simplest materials, it can include metal and therefore you can make structure out of metal and then you can send robots that will attach electronics and wiring onto the metal," Metzger said. "So by making the easiest thing, you've reduced the largest amount of mass that you have to launch."
Metzger said the first generation of machinery would be akin to the simple mechanical devices of the 1700s, with each new generation advancing quickly to the modern vanguard of abilities. They would start with gas production and the creation of solar cells, vital for providing a power source. Each new robot could add improvements to each successive model and quickly advance the mining and manufacturing capabilities. It would not take long for the miners to produce more material than they need for themselves and they could start shipping precious metals back to Earth, riding on heat shields made of the leftover soil that doesn't contain any precious material.
Perhaps the most unusual aspect of the whole endeavor is that it would not take many launches from Earth to achieve, Metzger said. Launch costs, which now run at best $1,000 per pound, would be saved because robots building themselves in space from material gathered there wouldn't need anything produced by people. Very quickly, only the computer chips, electronics boards and wiring would need to come from Earth.
"We took it through six generations of robotic development and you can achieve full closure and make everything in space," Metzger said. "We showed you can get it down to launching 12 tons of hardware, which is incredibly small." For comparison, that would be less than half the weight of the Apollo command and service modules flown on a moon mission.
The operation the scientists acknowledge, would take years to establish, but not as long as one might think.
The payoff for Earth would be felt when the first shipments of materials began arriving from space. A sudden influx of rare metals, for instance, would drive down the price of those materials on Earth and allow a similar drastic reduction in manufacturing costs for products made with the materials, Metzler stated.
The article was published in the Journal of Aerospace Engineering.
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