Mining in space

Private sector making giant leaps affordable

Paul Danish

The reason the dinosaurs are no longer around,” Chris Lewicki recently told a conference on extra-terrestrial mining, “is that they didn’t have a space program.”

No one laughed. The 45 mining engineers, robotacists, aspiring entrepreneurs and other specialists attending the Third Joint Meeting of the Space Resources Round Table and the Planetary & Terrestrial Mining Sciences Symposium, held June 4-7 at the Colorado School of Mines in Golden, are a crew that takes asteroids very seriously — both as an existential threat to life on Earth and as a business opportunity.

As does Lewicki. He is president of Planetary Resources, Inc., the Asteroid Mining Company. Planetary Resources made international news when it held a coming-out press conference in Seattle April 24 and announced 1) its goal was to mine near-Earth asteroids, and 2) it had the backing of some serious, high-profile, and deep-pocketed entrepreneurs, including Google Chairman Eric Schmidt, Google co-founder Larry Page, real estate and software developer H. Ross Perot, Jr., and filmmaker James Cameron.

The announcement, together with the successful launch of Space Exploration Technology, Inc.’s (SpaceX’s) commercially developed Dragon cargo-carrying spacecraft on the company’s Falcon 9 rocket, prompted the country’s space enthusiasts to prick up their ears like nothing in decades.

Lewicki said that in the six weeks since the press conference, Planetary Resources has received 2,000 job applications and 5,000 investment requests. And thousands of emails saying, in so many words, it’s about time, right on, at last and god speed.

The most striking thing in the outpouring, he said, has been “the element I never experienced in all my time at NASA, which was one of hope.”

Planetary’s business plan is direct and audacious:

First, it intends to prospect for resource-rich asteroids relatively close to Earth.

(Near-Earth asteroids are asteroids orbiting the sun within about 30 million miles of Earth’s orbit, which is relatively close compared to asteroids in the asteroid belt, which are roughly 90 million to 250 million miles from Earth. Some 9,000 near-Earth asteroids have been discovered in recent years, and the number is growing by about 1,000 a year. More than 1,500 of them are easier to get to than the moon, Lewicki said.)

Initially, the prospecting will be done with swarms of small orbiting space telescopes smaller than a lecture podium. (For comparison, spy satellites can be as long as an 18-wheel truck.) The company has already built prototypes. These telescopes can also be used for terrestrial imaging at a fraction of the cost of contemporary military and civilian observation satellites, which will make remote imaging from space available and affordable to a vastly expanded pool of new users — and will provide early revenue for Planetary Resources.

“The reason we are focused on tiny little telescopes,” Lewicki said, “is that they are really, really cheap.”

“We want to build Fords, not Ferraris,” he added. The orbiting mini-telescopes will be followed by telescopes to which propulsion and additional scientific instrumentation has been added. These will be sent for a close-up look at Earthcrossing asteroids, which are asteroids that cross Earth’s orbit. Several of these are seen for the first time each year. Planetary Resources wants to send interceptor missions to some of those that come closest to the Earth, which will allow it to quickly acquire data on several near- Earth asteroids.

Beefed-up versions of the interceptor craft equipped with lasers for deep space communications can then be sent to rendezvous with asteroids much farther from Earth and be put into orbit around them for extended data collection on the asteroids’ shape, rotation, density, and surface and sub-surface composition.

Watering holes

The resources the company will be looking for include metals, precious and otherwise, but heading the list will be water. Apart from being necessary to sustain life and being essential to a host of chemical and manufacturing processes, the water molecule can be split into hydrogen and oxygen, which can be used as rocket fuel. The ability to refuel spacecraft after they have climbed out of Earth’s gravity well would spectacularly expand humanity’s space-faring abilities.

“The water resources and the in-space use of the water resources is what allows you to do anything else in space,” he said.

That view was shared by a number of other conference participants.

“Access to water is the single most critical thing,” said Jim Keravala, chief operating officer of Shackleton Energy Company, a Texas start-up company that wants to mine water on the moon — two NASA missions conclusively established its presence several years ago — and turn it into rocket fuel, which it will dispense from a network of refueling service stations that it will establish in low Earth orbit.

The moon’s gravity is only one-sixth that of Earth’s, which means getting the fuel from the moon to the service stations would require only 1/14th to 1/20th as much propellant as launching a comparable amount from Earth.

“Water is the single most important locationdependent resource for a potential future human mission to Mars,” according to a paper written for the conference by a group of NASA and academic space scientists studying possible Mars exploration.

The consensus among conference participants extended considerably beyond the importance of water and included the future of human activity in space and a number of basic points of agreement that collectively amount to a shared vision of how humanity will expand into space.

Among them: • There can be no sustainable human presence in space without the exploitation of extraterrestrial resources. (In situ resource utilization, or ISRU, is the term of art.)

• The most important resource to find and exploit is water, followed closely by other “volatiles,” including carbon dioxide, ammonia and methane. The presence of these and several other volatiles has been detected on the moon, asteroids and Mars.

• Mining on the moon, asteroids and Mars will require the extensive use of custom-designed, self-replicating robots.

• Energy for extra-terrestrial mining operations will come from either solar or nuclear power.

• The early business opportunities for private space ventures include the production of rocket fuel for extra-terrestrial refueling of spacecraft, remote sensing from orbit and, possibly, solarpowered satellites that would beam electricity down to Earth.

• The private sector will take the lead in space exploration from now on. NASA’s role will increasingly become research, support and enabling. If space exploration isn’t profitable, it won’t happen.

• Success will depend on dramatically reducing costs (by at least an order of magnitude or more) and keeping them down.

• Success will also depend on “bootstrapping,” with self-replicated robotics.

The concept calls for simple robots to mine raw materials that other simple robots can use to reproduce themselves, and then more complex robots that will perform larger and more complicated tasks — eventually building an entire extraterrestrial industrial infrastructure.

• Extraterrestrial conditions, including temperature extremes, high vacuum, unearthly soils, low or no gravity, and so on, will pose unique challenges for mining, but will also present miners with some unique opportunities.

• The satellites and robots used for prospecting, mining and eventually manufacturing have to be small, affordable, expendable and replacable. Failure, and the ability to recover from it, has to be an option.

The new world

There is also agreement that the risks facing private-sector space ventures are enormous, but so are the potential payoffs — riches beyond imagination. Planetary Resources and Shackleton executives have not hesitated to compare the payoff, and the lure, to the discovery and settlement of the New World and the exploitation of its resources — only a lot larger.

“It will be tens or hundreds of billions a year,” Lewicki said.

Shackleton’s Kervala also put the returns “in the hundreds of billions of dollars.”

How long would it take to bootstrap the creation of a major extraterrestrial industrial presence? Only a few decades, in the estimation of four NASA researchers who studied the question. A team led by Philip Metzger at the Kennedy Space Center in Florida calculates that, thanks to advances in robotics and additive manufacturing (the process of making three-dimensional objects from a digital file with a device that builds them up layer by layer by spraying material like an ink jet printer), “it has almost become feasible to bootstrap a self-sustaining, selfexpanding industry” on the moon “at a reasonably low cost” during a period of about 20 years. The amount of equipment necessary to land on the moon to get things going would amount to as little as 12 metric tons delivered over the 20-year timeframe.

“The strategy begins with a subreplicating system and evolves it toward full self-sustainability (full-closure) via an in situ technology spiral,” they wrote.

“The industry grows exponentially due to the free real estate, energy and material resources of space. The mass of industrial assets at the end of bootstrapping will be 156 metric tons with 60 humanoid robots, or as high as 40,000 metric tons with as many as 100,000 humanoid robots if faster manufacturing is supported by launching a total of 41 metric tons to the moon.”

“Within another few decades with no further investment, it can have millions of times the industrial capacity of the United States … This industry promises to revolutionize the human condition,” they conclude.

Implementation of this grandiose vision begins with some nitty-gritty mining, and that’s where a mining engineer like Leslie Gertsch, a professor at the Missouri University of Science and Technology at Rolla, come in. Gertsch presented a paper pointing out that mining the lunar regolith (surface soils) for volatiles will involve more than just scooping the stuff into trucks and hauling it off for processing. Merely disturbing the regolith might be enough to cause the volatiles to sublimate (change directly from frozen solids to gases that dissipate in the near vacuum that passes for the moon’s atmosphere.)

Consequently, she proposes adapting a number of mature terrestrial mining techniques to mine them from below. These include long-wall mining, surface caving (where loose material is under-mined and allowed to fall into a drift) and horizontal directional drilling, borrowed from the oil industry.

Others think surface mining could be made to work. Bonnie Cooper of ESCG/Jacobs Technology, as well as her colleagues Kris Zacny of Honeybee Robotics and D.S. McKay of NASA, proposed an approach to mining lunar regolith called pneumatic separation. The process takes advantage of experimental evidence that the finer the grain size of lunar soil particles, the higher their hydrogen content. (The hydrogen in question is believed to come from the solar wind. Hydrogen can be used to make water, or as rocket fuel. Cooper also points to evidence that lunar water deposits aren’t confined to permanently shaded craters at the Moon’s poles, but that small amounts of water are also present in soils in the moon’s equatorial regions.)

The system Cooper proposes is a wheeled mobile extractor that uses small puffs of gas to stir up the finest and most hydrogen-rich particles (just a few microns in diameter), which would then be trapped and stripped of their hydrogen and any other volatiles they might contain.

“Pneumatic separation and transport gives us the potential to obtain the vast majority of the moon’s resources in a simple and economical way, anywhere on the moon,” she says. Cooper’s colleagues at Honeybee Robotics have already performed a proof-of-concept experiment of a pneumatic transfer system in a vacuum chamber.

Robot with an auger

The Lunar Crater Observation and Sensing Satellite (LCROSS) mission in 2009, which crashed a satellite into a crater while a second satellite in orbit measured the chemical composition of the plume, indicated that the concentration of water in the frozen lunar regolith is 5.6 percent. Other volatiles, such as mercury, sodium, sulfur dioxide, carbon dioxide, formaldehyde, ammonia and methanol, were also detected. When robotic prospectors land on the moon and Mars in search of water, they will not be chipping away at frozen lunar and Martian soil with pick-axes or any other conventional extraction techniques.

“Icy soils are harder than concrete,” said Zacny. His company, Honeybee Robotics, specializes in making advanced robotic and spacecraft systems.

And that’s on Earth, where frozen soils were measured at 40 below zero, which is positively balmy compared to low temperatures during the lunar night (which lasts two weeks) and the Martian winter. Moreover, any frozen water in exposed lunar or Martian soil would quickly be lost through sublimation.

However, if picking at icy regolith is a non-starter, drilling is another matter. So Honeybee designed a wheeled prospecting robot fitted with an auger that retains the soil on its flutes. The auger is then raised into a cylindrical extraction chamber, which is sealed. Once the auger and the soil are in the extraction chamber they are heated, and the water (and any other volatiles that might be present) is removed as vapor to a tank, where it condenses. The auger is then lowered out of the extraction chamber and spun in reverse to get rid of the dried soil. The robot then moves on to the next drilling site and the process is repeated.

Honeybee demonstrated drilling to one meter in ice and ice-cemented ground to prove the concept. It also built a scaled model of the extraction system to demonstrate the feasibility of water extraction. It was tested in a “Mars chamber” and successfully recovered more than 60 percent of the water present, Zacny said.

One problem facing those who want extraterrestrial mining robots is finding suitable test sites. Lunar regolith may be granular, but it is nothing like sand on Earth. And it’s in short supply on Earth. The Earth’s total supply of lunar soil currently consists of whatever was scooped up and returned to Earth by the Apollo astronauts.

A volcanic solution?

One solution, proposed by Pacific International Space Center for Exploration Systems (PISCES) of Hilo, Hawaii, is the establishment of a test center high on the slopes of a volcano on the island of Hawaii. According to John Hamilton of PISCES, the island has soil at 9,000 to 11,000 feet that is analogous to Martian soil.

The basaltic rock is also fairly similar to lunar regolith, and apart from testing sampling and mining robots in it, PISCES is investigating using it for construction materials. Lunar regolith can be formed into building blocks by sintering, a process that involves the controlled melting of a powder at the grain boundaries to produce optimum mechanical properties. They could be used for paving launch pads, providing radiation shielding and constructing buildings, including human habitations, eventually. These techniques could have terrestrial uses as well. The paving part has gotten the attention of the Hawaiian legislature, which is interested in finding ways to pave the state’s roads without asphalt. (Currently, all the asphalt used in Hawaii has to be shipped in from the mainland.) The terrestrial uses for basaltic construction materials — blocks, bricks and paving — could provide PISCES and other companies with early revenues and a path to develop their technologies.

A different approach to testing is to manufacture material that simulates lunar and other celestial regoliths. Zybek Advanced Products (ZAP), a Boulder company, is doing just that. The company, which has produced lunar simulants for NASA and the U.S. Geological Survey, makes the material using a system that can generate plasma temperatures approaching 20,000K. The system produces glass from a wide variety of feed stock materials. The glasses are then broken up into jagged particles of sub-micron to 100-micron size, which simulate those found on the moon. Company officials think there are a number of terrestrial applications of its technology as well.

NASA has funded a lot of robot mining research over the years, but it may have stumbled onto a way of getting a lot of new, low-cost technology.

The space agency runs an annual competition in which university studentdesigned lunar mining robots compete against each other. The machines are required to excavate and load a minimum of 10 kilograms of simulated lunar soil from a 25 x 25 foot bin of the stuff in two separate 10-minute timed competition events. The robots can be either remotely controlled or autonomous.

Last year, 55 teams entered the contest. “NASA got 55 prototypes for free. I call it crowd-sourcing,” said Robert Mueller, chief of NASA’s Surface Systems Office at the Kennedy Space Center. He said the competition prods NASA’s engineers to think outside the box.

The event’s corporate sponsors include Caterpillar, Newmont Mining, Harris and Honeybee Robotics. Caterpillar has been sufficiently impressed by the work of some team members that it has subsequently hired seven of them.

The issue of asteroids crashing into the Earth didn’t receive a lot of attention at the conference, but one point was alluded to several times — that space prospecting activities can’t help but lead to a boom in the discovery of asteroids, the tracking of their orbits (how else could you stake a claim on a lode zipping around at 80,000 miles an hour?) and, therefore, the identification of potential threats.

If and when a mature asteroid mining industry emerges, it would likely have the resources available to either divert a threat or, given sufficient warning, mine it out of existence.

Which means the chances of humanity getting sucker-punched by an asteroid the way the dinosaurs were will take a giant leap downward.