Together, all of the asteroids in our Solar System add up to only about one hundredth the mass of Earth. Yet these asteroidal resources could support a population thousands of times greater than our home planet. On Earth, we can only mine the outer few miles of crust, and drill only a little deeper than that. But asteroids, with nearly no gravity and no internal magma, are entirely accessible to our technologies. And of course, they are dead rocks with no ecosystems to disrupt.
Asteroids mostly reside in a wide range of orbits between Mars and Jupiter. There are an estimated 1,000,000 asteroids in the main belt that are at least one kilometer (0.6 miles) in diameter. Most of these are rich, carbonaceous chondrites, full of the stuff of life. Perhaps 5% are nickel-iron. Millions more reside in the libration points in Jupiter’s orbit. Thousands more orbit inside of Mars’ orbit, and some are inside Earth’s orbit. And this doesn’t include the small asteroids and fragments measuring less than 3 meters in diameter, of which there may be millions.
DSI’s first choices for utilization will be Earth-crossing asteroids, the same asteroids that NASA is cataloging because they pose a potential threat to the planet. Given proper timing, some of these are even easier to reach than the Moon. And these Earth-orbit-crossing “potentially hazardous asteroids” (PHAs) are plentiful. Over a thousand are known whose diameter exceeds a kilometer.
There are likely 10,000 or more PHAs that are 300 meters (1,000 feet) in diameter; these are large enough to destroy entire states or countries. We believe there are 100,000 or more PHAs that exceed 100 meters (330 feet) in diameter, large enough to destroy a city. And there are millions in the 30+ meter (100+ foot) diameter range.
A typical 50-meter diameter asteroid is a solid body massing over 200,000 tons, of which as much as 40,000 tons is iron-nickel alloy. Anything smaller poses no danger to the Earth, as they can’t penetrate the atmosphere intact. Yet they still contain valuable resources that DSI will collect – at no risk to Earth – and harvest to support an expanding, abundant civilization.
More than 9,100 near-Earth asteroids have been counted, with more than 900 new NEAs found annually in recent years. To mine an asteroid, one must either travel to it with a complete mining and processing plant, or bring it back to a stable location near Earth. Most NEAs come near Earth only once every five to ten years, so shipping to and from a free-flying asteroid has its challenges. However, some are small enough to be moved to stable locations near Earth for processing.
The 1,100 of these moveable rocks discovered so far are estimated to represent less than 1% of the total available.
Even with “discovered” NEAs that have known trajectories, their size and composition can be hard to determine, especially for the smaller ones. Water-rich types generally are coal-black, reflecting only one or two percent of the sunlight they receive. Metallic asteroids reflect 10-15% of sunlight. This means that any smudge of light seen by telescope could be from a large-but-dark water-rich asteroid or a small-but-brighter metallic asteroid – both would reflect the same amount of light.
Deep Space Industries will use existing and new data from the many ground based telescopes and ongoing government funded space missions to explore NEOs and when necessary send out inexpensive small probes to investigate potential targets so their actual size, rotation, and resource type can be confirmed. These “Firefly” missions begin in 2015, using inexpensive cubesat technology from established suppliers.
Transporting / Safety
Near Earth Asteroids pass by Earth rapidly and usually don’t return for a decade or more. This makes it impractical to establish a mining operation on them, so the solution is to move them to stable locations near Earth. One such location is orbiting the Moon. Additional areas include the Earth-Moon libration points where the pull of the Moon is almost exactly balanced by the gravity of Earth or in High Earth Orbits (HEO). Factories at an Earth-Moon libration point would be economically positioned to serve in-space markets on the Moon or in Earth orbit – either way is “downhill” from the libration point, gravitationally speaking.
For safety reasons, Deep Space Industries will limit itself to moving asteroids with diameters less than 30 meters in the vicinity of the Earth. If DSI were to lose control of an asteroid this size and it approached Earth closely, it would break up harmlessly in the atmosphere. In other words, our destinations are far enough from the Earth to be safe, but close enough to serve as sensible processing locations and near our customers.
A captured asteroid puts vast resources into easy reach, while protecting the Earth from a future impact at the same time. Even a smaller Earth-crossing asteroid such as Apophis (only 270 meters wide) contains twenty-seven million tons of material, potentially including millions of tons of water, iron, carbon, nitrogen and other materials valuable to life in outer space.
Asteroids come in three main types: carbonaceous, metallic, and stony. DSI will harvest the water-rich carbonaceous NEAs to produce water for in-space life support, radiation shielding and propellant. The International Space Station and future Bigelow Aerospace habitats, for example, require tons of water and propellant every year hauled up from Earth at great expense. They also require propellant to restore their altitude after the gradual deceleration caused by atmospheric drag.
Communications satellites – there about 300 at work now – run out of fuel after eight to fifteen years. Propellant from asteroid processing could double their lifetimes, creating enormous value for commsat owners and lower prices for commsat users.
In addition to raw materials, an asteroid provides protection. In its most raw and unprocessed form, ground asteroidal material has great value in space as a means to “shield” human space facilities from harmful cosmic rays and other hazards. Ten or fifteen feet of asteroidal rock will provide the same degree of protection from meteors, solar flares, and cosmic rays as our atmosphere on Earth. DSI will be able to provide this material to early outposts beyond the protection of the Earth’s magnetic field. Along the way we can process the material to extract ice and other “volatiles”, especially oxygen and hydrogen.
Future crewed expeditions to Mars likely will hinge on the availability of low-cost fuel created in space, because 90% of their mass will be propellant. If Mars missions can be launched “dry” and tanked up after reaching orbit, this will eliminate 90% of the launch costs for expeditions to the Red Planet. When we begin regular flights to and from Mars, such as Buzz Aldrin’s “cycler” idea, even greater markets will be created for shielding materials and propellant.
DSI will mine metallic asteroids for the steel and other alloys that can be made from them. The company is developing a patent-pending Microgravity Foundry that can transform crushed metallic ore into precision metal parts using a handful of moving parts in a compact device. Space outposts to conduct research and produce high-value products for Earth will be fabricated primarily in space from DSI mini-factories, at far less cost than launching them from the ground.
A huge market will be construction of Space Solar Power Satellites to beam power down to terrestrial electric utilities. Space solar power is available day or night, produces no radioactive waste and adds no carbon to the Earth’s atmosphere.
In order to carry on a useful conversation about asteroids, we have, for our own purposes, developed a workable set of descriptions. The terminology may not be perfect, in fact there are exceptions and anomolies in each set and definition, but it is, as they say: “close enough for ‘rock’ and roll.”
10,000+ meters: Huge
An Earth impact would be an “Extinction Level Event.” Call Bruce Willis and Morgan Freeman… “Game over Man!”
3,000+ meters: Very Large
On the verge of being itty bitty semi-planetesimals. If one is coming call your mum, write your will. The last day of life on Earth. An Earth impact would be a major civilization destroying, climate changing and devastating event.
1,000+ meters: Large
(The ones we can see if they are favorably positioned, at least in principle).
Still a DeathStar. A billion+ tons. A very bad day for life on Earth. Devastating, climate changing, city destroying if they hit. Also could be hollowed out and rotated for a cozy little space colony.
300+ meters: Medium
50-500 million tons. Note that (with few exceptions) these will be rubble piles. Major calamity if in populated areas. Easy to grab pieces for mining and use. Good for hiding from Darth Vader and Reavers.
100+ meters: Small
1.5-15 million tons. Many are monoliths. Still dangerous, may make it most of the way if not all the way to the surface. Sentinel will find most of these if they are Earth-crossers.
30+ meters: Very small
50,000-500,000 tons. Usually harmless. All monoliths. Sentinel will find many of these if they are Earth-crossers.
10+ meters: Tiny
1,500-15,000 tons. Size of a building. These are completely harmless! One burns up annually. (Make a wish! But don’t stand under them – just in case.)
3+ meters: Large Boulders
(50-500 tons). The size of a bus. One breaks up in the atmosphere every month.
1+ meters: Boulders
Less than harmless. Not exactly “cute” like pet rocks, but close. 1.5-15 tons.
Note – We really need to get out there and find them all….