Thursday, March 21, 2013

The Universe: Living in Space

Here's one I never thought I'd be writing about. The History Channel has presented a science documentary series called "The Universe".  I watch it.... a lot. I'm a subscriber. I was a little surprised to find something questionable enough here to warrant a comment from me. Particularly when it wasn't just an off-hand comment, but a thoroughly thought-out segment. And particularly not when the idea was floated by Dr. Michio Kaku, one of the most successful popularizers of science since the late, lamented Carl Sagan.

Questionable Judgement

The thing that perked my ears was the suggestion that Mars colonists would benefit from asteroid mining. The depiction here basically took the form of deflecting an iron asteroid out of its orbit so that it lands on Mars. Then, of course, the colonists would simply take the iron from it at their leisure.

It's not that the science here is bad. It's pretty sound reasoning as far as it goes. No, it's that the judgement is really, really questionable.

All other difficulties aside (such as coming up with the energy to accurately deflect a rock of that size moving at that prodigious speed), there's the obvious danger factor. An asteroid of the size discussed (about a kilometer across), would land with kinetic force rivaling the most powerful nuclear weapons. Surely you'd want your mine close enough to your colony to make the commute reasonable, but it's a fine needle you'd have to thread to not wipe out your colony with the delivery.

Better Options

It's not like they need to do that. Mars is "The Red Planet" for a reason; that reason being that it's literally covered with rust. Iron oxide. On Earth we reduce that to iron by heating it with carbon. That doesn't exactly work on Mars, as elemental carbon is rare as unicorn farts, but it's still do-able in a couple of ways.

First, Mars does have water, at the poles. Electrolysis of the water would yield hydrogen gas and oxygen (and this makes it a ready source of oxygen for breathing). The hydrogen thus released could be used to smelt iron, as iron oxide combined with hydrogen yields elemental iron plus water (Fe2O3 + 3H2 -> 2Fe + 3H2O). So for the expenditure of some energy you get oxygen to breathe, iron to build with, and you even get your water back! With a bit of work, you might even be able to construct a roving foundry that spits out iron bars and breathable air from the sand it scoops up and recycled water. Fanciful, I know, but it's no more fanciful and it's a lot safer than pelting your colony with giant space bullets.

A second way is to use the carbon dioxide that composes the bulk of the Martian atmosphere. Throw some serious heat at it and it breaks up into carbon monoxide and oxygen. Once again we have oxygen to breathe, and in this case the carbon monoxide reacts with the iron to form elemental iron and more carbon dioxide (Fe2O3 + 3CO -> 2Fe + 3CO2). Since I don't much like carbon monoxide, and it's tricky to separate it from the oxygen so the latter can be used safely, I prefer what I think is the safer hydrogen reaction, above.

Be sure that either of these options is better than dropping an island on your head, so I'm really confused as to why this flight of fancy ever entered the conversation. Despite that bit of puzzling speculation, I still recommend the series and this episode. HERE IT IS.


  1. I've come across the idea of impacting meteors/asteroids/comets on Mars as a way to import large quantities of volatiles (and/or thermal energy), for the purposes of eventually terraforming it. But this may be the first time I've heard it suggested as a way to produce a mine-able mineral resource.

    Googling for a terraforming reference, I came across this Q&A page (, which also happens to be Dr. Kaku's blog. He briefly addresses the issue there.

    I'm not sure where I stand on the issue -- how well could they control it, and contain potential damage? The good (?) news is that we probably have a long time before we're in a position to start making those decisions.

    I'd assume there wouldn't be much in the way of colonization before such an effort is undertaken (maybe a few small outposts), and if volatiles and energy is the main concern, it would be better to keep the impact far away from those. But you could always establish a new colony at the impact site at some later date, if you wanted to mine it.

  2. I'm not sure I'm up to the math, but I'm skeptical that we could generate enough heat from asteroid impacts to generate a sustained heat. It seems to me that any change of this sort that's small enough for us to effect would be insufficient to be useful in the long term. To truly terraform, you'd have to heat the core, not the surface, and I suspect that requires an impact far larger than we could manage.

    Besides that, heating a planet core that way would render the surface uninhabitable on a timescale measured in millions of years, and we can't even pass a budget for one. I don't think we have that kind of forethought in us.

    Finally, given the wholesale destruction of the planetary geology and lost scientific opportunities, would we REALLY seriously follow through with terraforming ANY planet whatsoever? I truly think there's as much chance of that as there is of clearing the Amazon for suburban tracts. It might be better to consider "Caves of Steel", along with domed parks as a better alternative. Adapt to the place, rather than adapt the place to you.

  3. I'm not sure about the math myself, but I'm also not Dr. Kaku. I guess if one asteroid doesnt' do the job, there's a bunch more where it came from?

    I vaguely remember reading some of the Mars Trilogy by Kim Stanely Robinson back in the 90's (I don't think I ever finished it). A major theme in the first book was actually a huge political divide that arose among the first Martian settlers about whether to terraform Mars for human habitation (the "Green" faction) or to preserve it for scientific study (the "Red" faction). It probably ended up leading to a Martian Civil War of some sort, but I don't remember well enough (of course, they also rebelled against Earth). Obviously, the Green faction ended up winning, since the books are titled (in order): "Red Mars", "Green Mars", and "Blue Mars".