The Perils of Asteroid Mining.

Let me start by saying that when I was young I wanted to be an astronaut.  I was always fascinated with space travel, and envisioned myself as an intrepid spaceman like Captains - Kirk, Picard, Buck Rogers, Malcolm Reynolds, or Han Solo.  Flitting about the galaxy to visit far off planets, and have harrowing adventures... *sigh*.  Sadly, I went to college and studied science, and those dreams were dashed by the stark reality that separate science fiction from science fact.  I still dream, as a science fiction author, but I’ve grown to a point where I can understand the difference between reality and fantasy.

Recently I read several articles about various people and private organizations who want to make reality out of what has been, up to now, science fiction.  I was very interested in these concepts initially, but I’ve had a chance to think them over, and I have to shake my head that seemingly intelligent people are behind these ideas.  What’s more troubling is that people like Neil deGrasse Tyson have publicly endorsed some of these ideas.

As I’ve said, I like to dream too, but seriously think about things more objectively.  Ideas like mining asteroids for minerals, establishing a permanent colony on Mars/Moon, or building a working starship Enterprise.  The mind fairly boggles.

The sanest of all these schemes is mining asteroids, but even then, I don’t think people really have thought things through.  Before you jump up and down and rant about how this is totally possible understand that I’m not saying that it isn’t possible...it just isn’t very practical.

Let’s start with the whole mining thing.  Mining is difficult in the most ideal conditions here on earth.  This is where we have an oxygen rich atmosphere, so humans can do the labor needed to dig, plant explosives, remove the mineral rich rock/earth, and repair equipment.  It is hard, dangerous work.  Equipment breaks all the time, and needs constant upkeep to keep the industrial strength equipment working properly.  This is a lot easier in warmer parts of the world, but in the far northern regions of the world, (I’m looking at you Canada) equipment breaks due to the extra stresses caused by bitter cold temperatures.
 

Space is very cold, or very hot...depending on how the sunlight hits you (more importantly how close you are).  That is the reason why spacesuits are so bulky.  Not only do they have to have a lot of insulation, but also they need a cooling system to keep the astronauts from getting heat stroke.  Even the space shuttle had to rotate its thermal shielding tiles to the sun and open the bay doors so the excess heat wouldn’t roast the crew.  That’s heat, now for the cold.  

Once you’re out of the direct light of the sun, the temperature drops precipitously.  It can get near absolute zero in some spots, and even if it decides to be on the warm side, it can be -250 F and colder.  Even at those relatively warm temperatures tungsten carbide drill bits used for mining can shatter like glass. 

Asteroids, of course, do not just sit still.  They rotate, and orbit, so they are constantly moving from one temperature extreme to another, similar to a roasted pig on a spit.  This causes constant expansion and contraction of, not only the asteroid, but the robots sent to do the mining.  Oh, didn’t I mention the robots?

To my knowledge, not a single asteroid has an atmosphere.  That means that sending humans requires a lot of oxygen be shipped up with them, and that gets so expensive that billionaires can’t even afford to finance the mission, so a robot has to do the job.  These robots would have to be made of some of the most expensive, and durable materials available in order to do their job, because there isn’t anyone that can fix them if they break.  You see, even as cute as the self-repairing robot Wall-E may be, we haven’t made anything that can function like that.  With no humans around to fix the darn thing if it hits something hard, say a vein of pure carbon crystals (diamond, or even worse aggregated diamond nanorod) a multimillion-dollar robot could turn into a multimillion-dollar boat anchor.  

Now I’m certain the engineers on this project have thought of that, and have made the thing as tough as possible.  Their jobs depend on their ability to solve problems like the effects of wild temperature variation, and mineral density and hardness.  There is still the matter of micro gravity.  I know you’re saying weightlessness, but that isn’t entirely correct.  Even with small 4 m asteroids there is some gravity, but it isn’t enough to keep a robot from flying off uncontrollably into space if it did something like apply a force...like drilling/digging or trying to anchor itself with gas propelled grapple guns (think Batman).  This is all due to this little known law in physics called Newton’s Third Law of Motion.  I think it was something about a force having an equal and opposite reaction, but I’m sure the engineers have thought of this too.  Although, when I saw the concept graphic it showed tiny little robots munching away at the surface of an asteroid like a Roomba on steroids, and nothing really anchoring it.  I’m sure that the CGI animators forgot that little detail when they made the clip.

Then there is the matter of fuel.  Rocket fuel is expensive, and takes up space.  The engineers say they have this problem licked.  When they arrive at the asteroid, they mine it for water, which can be turned into rocket fuel.  This is where I start to get skeptic.  First, pure water is a rare thing.  It’s so scarce in space that it’s worth more than gold.  That’s because it isn’t usually found in liquid form, except in a narrow zone around a star’s colloquially called “Goldilocks Zone”.  Water is usually found in the form of solid ice, but in this habitable zone, it’s liquid.  The asteroids being considered generally spend most of their time in this orbit.  While it would be possible to mine the water, and separate it into oxygen and hydrogen, it is difficult and very dangerous.  I’ll explain soon.  Second, water is a universal solvent, meaning that any minerals it meets can dissolve.  This changes the water into a solution that can be quite entirely not unlike water.  Thus, when the robot attempts to separate out the hydrogen from the oxygen, there are contaminants that can alter the chemical composition of the fuel, making it worthless as a propellant.  Now for the real kicker...

Water is a simple molecule.  It is two hydrogen atoms bonded to an oxygen atom.  Separately they are very reactive atoms.  When the two combine to form water, the reaction is energetic.  There is so much energy released that it makes it a great rocket propellant.  It’s highly combustible nature makes it extremely hazardous when not handled properly.  After the reaction occurs, the resulting byproduct water is a very stable non-reactive solvent.

The easiest way to transform water into the two separate gasses is to apply an electric charge to an anode and a cathode.  This causes the bonds holding the molecule together to break, and you get hydrogen and oxygen gas; then you can use them as fuel.  Using electricity in this process presents its own set of challenges.  All it takes is one spark in the right place and you have a detonation that could cripple or destroy the rover.  There are other methods of breaking the molecular bonds, but they still create a highly explosive pair of gasses.  

This is all assuming that you have a pure source of water to begin with.  Unfortunately, pure water doesn’t exist in nature.  Most water on the earth is saturated with mineral salts.  We call it seawater.  Fresh water also has dissolved minerals in it, so it also has contaminants that can make it useless as a fuel. The only way to get pure water is to distil it, and that is very difficult in a microgravity environment, but not impossible.  Then there is always the possibility that there won’t be enough water to convert to fuel to get the spacecraft back to earth.

All of this discussion is moot if there isn’t water on the asteroid in the first place.  Unfortunately, you won’t know for sure until you arrive, and even then, the water may be impractical or impossible to get.  If you send a mission to an asteroid that has no water, or you are unable to get to the water, you’ve just wasted hundreds of millions (if not billions) of dollars with no way of recouping the cost.

Now let’s just say that we’ve managed to overcome all the obstacles in mining, and we have our payload of ore.  Now we have to get it back to earth – without killing anyone on the ground, or losing it in the ocean.  Bear in mind that our strongest re-entry parachutes can only handle 40,000 pounds.  That’s a lot of ore, but no where near the 320 tons that a single Komatsu 930E (the dump truck used by Rio Tinto at their Kennecott mine) can haul in a single load.

The last major obstacle is the most obvious – cost.  What is the point of going to mine these minerals if you can’t recoup the cost of the expedition, and make a profit in the process?  Let’s start with the upfront cost.  The general rule of thumb on space travel is to take the weight of the payload (robot rovers) and then get the same weight in gold. That’s right, gold.  As of 7/16/2012 (the time this article was written) gold was valued at $1,596.10 per troy ounce (31.1034 grams).  An Atlas V (the one used to send rovers to mars) can lift 8,750 – 28,660 pounds into geosynchronous orbit (where communications satellites are sent, or roughly 26,000 miles above earth).  It doesn’t list the maximum weight for interplanetary missions, but let’s assume that it is halfway between the minimum and maximum for geosynchronous orbit.   Let’s use 19,910 for the sake of this discussion.  That means that the payload is 318,560 standard ounces.  Although gold is sold in troy ounces (1.097 standard ounces) I’m going to use the standard ounce for the sake of this discussion and convert straight over (yes, I’m aware of the mathematical inaccuracies of doing this).  That means that our payload will cost $508,453,616 to launch.  This price does not include the cost of the rovers; it’s just to send them to space.  Assuming that the rovers will cost about the same amount to manufacture, that brings our total to around one billion US dollars.  Now our 40,000 pounds of cargo can be sold.  

Since gold is the most precious metal on the NYMEX exchange we’ll assume that our ore is 100% gold (highly unlikely, but let’s be generous here).  That means that our maximum return will be $1,021,504,000; not much profit on a billion dollar investment.  Now let’s look at a profitable terrestrial mining giant like Rio Tinto.  In 2011, they reported a Consolidated Sales Revenue of $60,537,000,000 with $36,260,000,000 in Net Operating Cost.  Anyone looking at the comparative balance sheet would instantly choose the more traditional, and considerably more profitable, terrestrial based mining operation.  

Although it isn’t profitable on the financial side, the cool factor is off the charts.  Unfortunately, cool only goes so far.  In the end, everything revolves around money.   Even though it’s financed by billionaires, they still expect a profit.  They didn’t get to be billionaires by squandering their money on losing enterprises.  This basic principal can’t be overlooked, even in science fiction (Dune’s central plot focused on the economics of a single rare commodity).  Even if they could charge more for minerals that were mined in space, they would have a tough time making it competitive.  Like any commodity, it is what people are willing to pay that dictates its worth.  Gold’s value changes day to day based on how much people are willing to pay for it.  It doesn’t matter where the gold was mined.  Gold mined in space will have to sell for the same amount as gold mined here on earth, because what you’re essentially paying for is the metal, not the mining method.  

Remember that I’m not anti-space travel.  I’m just pragmatic when it comes to reality.  There may come a time when space mining will be more economically viable, but it’s just too expensive right now.  Once we have a method of propulsion that can reduce the cost to launch and subsequently recover the minerals it will be viable, but right now the cheapest method is chemical propulsion.  What we are left with is an expensive endeavor that will unfortunately wind up costing more than it's worth, and that means it won't be around long after it takes off (I'm sure that's a pun somewhere). 

There is always the environmental issue of space junk, but I’ll leave that subject for another post.