Reddit reviews Entering Space: Creating a Spacefaring Civilization

Here's the line directly from the source ["Entering Space: Creating a space-faring civilization"] in the Wiki citation:

>In certain ways, Titan is the most hospitable extraterrestrial world within our solar system for human colonization. In the almost Earth-normal atmospheric pressure of Titan, you would not need a pressure suit, just a dry suit to keep out the cold. On your back you could carry a tank of liquid oxygen, which would need no refrigeration in Titan's environment, would weigh almost nothing, and could supply your breathing needs for a week-long trip outside the settlement.

>A small bleed valve off the tank would allow a trickle of oxygen to burn against the methane atmosphere, heating your breathing air and suit to desirable temperatures.

>With one-seventh Earth gravity and 4.5 times terrestrial sea-level atmospheric density, humans on Titan would be able to strap on wings and fly like birds. - (Just as in the story of Daedalus and Icarus -- though being more than nine times distant from the Sun than Earth, such fliers wouldn't have to worry of their wings melting.)

>Electricity could be produced in great abundance, as the 100 K heat sink available in Titan's atmosphere would allow for easy conversion of thermal energy from nuclear fission or fusion reactors to electricity at efficiencies of better than 80 percent.

>Most important, Titan contains billions of tonnes of easily accessible carbon, hydrogen, nitrogen, and oxygen. By utilizing these elements together with heat and light from large-scale nuclear fusion reactors, seeds, and some breeding pairs of livestock from Earth, a sizable agricultural base could be created within a protected biosphere on Titan.

We already know how to create energy with antimatter, the problem is "Where do you get the antimatter?"

Antimatter does have the highest energy to mass ratio of anything we know, but it is very scarce. Our universe is about 5% matter, 20% dark matter, and about 75% dark energy. Antiparticles exists in nature, from cosmic ray collisions that generate them and such, but not very much, and certainly not the amounts expected, which leads to a complicated and open question: (http://en.wikipedia.org/wiki/Baryon_asymmetry) of why not?

What's much more likely for the future is the harvesting of http://en.wikipedia.org/wiki/Helium-3 which is the leader in energy per mass ratio (excluding the aforementioned antimatter) It could be mined from the moon and then used in fusion generators to become our future energy source. Additionally, there might be potential to mine it from the gas giants, which would turn places like Jupiter into kinda gas stations on our way out of the solar system.

On an interesting side note. Y Combinator, the folks that invested and created Reddit (Alexis, one of the founders of Reddit is now on their board I believe) just funded a new startup http://blog.ycombinator.com/y-combinator-and-mithril-invest-in-helion-yc-s14-a-nuclear-fusion-startup This is an interesting tactic because a big complaint among scientists is not that fusion is impossible, but that it is about funding. For example this chart was posted somewhere else on Reddit a few weeks ago: http://i.imgur.com/JyUZDe2.jpg

A great primer in this subject I'd recommend would be Entering Space I say it is a great primer because it did do a great job with things like Helium-3 and or how you would need to slow down your solar sail ship, etc. It is a good read and written by http://en.wikipedia.org/wiki/Robert_Zubrin

>Ganymede

Right off the bat I disagree. Jupiter gives off way more harmful radiation than Saturn, and because Ganymede is a vacuum, any colony would either have to be underground or be heavily, heavily shielded. Titan's atmosphere would do the same thing for colonists that Earth's atmosphere did for us: shield us from radiation.

> Stonger gravity

This is the only point that I agree would make Ganymede more attractive, but when you know what you're getting yourself into as a colonist in space, and humanity at that point has mostly likely already dealt with 1/6 g (the Moon) or 1/3 g (Mars), I really think this will be a smaller issue than it's made out to be.

> tons of water

That's great! I love water! But did you know...Titan also has a lot of water? Like, 40% of the planet is composed of water ice? And most likely contains subterranean liquid oceans of its own? This is a moot point when both moons are practically drowning in the stuff.

> better than Titan's atmosphere / cause a big explosion

Two words: positive pressure. If a hab is pressurized to the point that only air can leak out, this is a moot point as well. Not to mention that despite the presence of methane, the atmosphere is mostly nitrogen, and methane there exists in the same way that clouds and fog exist here. Not to mention that the methane in the atmosphere and other hydrocarbons provide a lot of volatiles that can be used as fuel, fertilizer, in industrial chemical processes, etc, etc. This a non-trivial advantage over Ganymede, and honestly, any other Ganymede-like satellite. The benefits of the presence of so many hydrocarbons to a colony's standard of living and economy would honestly be the number one reason to put one there in the first place.

> colonize the far side of a tidally locked one

Not a problem, thick atmosphere is the best shield at the best price.

> which as he said

This is one article. There is a lot of literature out there that might change your opinion on this.

Sorry for the lengthy response. I'm not at all salty, as the tone of this whole comment might sound. I'm an aerospace engineering intern, and near-future space exploration and (hopeful) colonization is an enormous passion of mine. While I think colonizing Ganymede is on its own merit a good idea (colonizing anywhere in space is a good idea), I think Titan is just a better prospect in comparison.

Cheers

Entering Space: Creating a Spacefaring Civilization - Robert Zubrin

http://www.amazon.com/books/dp/1585420360

This is one of my favorite books of all time and I think this guy is some kind of former engineer for NASA (I could be wrong, I'm too lazy to fact check myself) but I do remember that all the technologies he discusses could be created today - there's a lot of stuff in the book that seems far-fetched but he says the tech exists to implement it right now.

The Case for Mars and Entering Space are excellent reading for anyone interested in the future of space exploration. Or blowing up kerbals.