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Comment by gpm | Hacker News Reader

Musk is very clear that his plan is to establish a self sustaining colony, not another 'footprints' mission, and not a colony that needs to be sustained via continuous resupply.

Mars has several advantages, you can pretty much google this and get better arguments then I'm able to make here. But here are a few key points.

- Earth like day period, 39 minutes longer versus almost a month longer than earth.

- More stable day-night temperature

- More gravity

- A weak atmosphere (versus none), and the capability to retain a earth like atmosphere.

- Easy access to Water, and CO2. Important for growing plants and making rocket fuel amongst other things.

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Are we sure the water's easy to access? From what I've seen, it evaporates really fast and the atmosphere is being stripped from the planet.

Poles

Well, easy compared to anywhere else we can go.

We aren't really looking for liquid water [0], as you say that evaporates pretty much instantaneously. Rather we are looking for ice, the pheonix lander confirmed the that this exists naturally on mars [1]. In the worst case water bound to the soil that can be baked out [2].

As for the atmosphere being stripped away, that's not really a concern on time scales humans care about. Though I've heard people talk about setting up a artificial magnet field to reduce the amount of radiation you receive, which should also prevent this.

[0] Well we are, but as a scientific curiosity not as a way to sustain a colony.

[1] http://www.nasa.gov/mission_pages/phoenix/news/phoenix-20080...

[2] http://www.space.com/22949-mars-water-discovery-curiosity-ro...

In the short term, you are either strip-mining soil to collect ice crystals, which you melt and store inside, or drilling a well (and piping it inside). You would grow food inside pressurised tents.

In the long term, mars lost its previous atmosphere over billions of years. If you have the technology to rebuild an atmosphere in human timescales (few hundred or thousand years) the atmospheric loss is small enough that it almost becomes a rounding error. Maintaining it should be easy.

You can't beat Earth for easy access to liquid water. But you can easily beat the Moon. Mars beats the hell out of the Moon on that score.

I have to wonder what the heck a "self-sustaining" Mars colony would export to Earth to pay for all the stuff they need to import.

Just look at people living in the Arctic: everything is imported, basic necessities are expensive, and getting replacements could take weeks.

Now imagine that you're on a different planet, and there are only a few firms that CAN resupply, and they'll only do it if you can compensate them sufficiently.

Better hope the colony is built on a platinum and rhodium mine!

I think "self-sustaining" in the context means that if Earth dissapears, explodes, turns into grey goo, or otherwise becomes unavailable, the Mars colony stands a chance of surviving indefinitely.

Yes, it's a hugely ambitious goal.

"Self-sustaining" by definition means able to survive indefinitely without importing anything from Earth.

Just few things needed for that

- mining industry

- chemical industry with thousands of end products.

- biochemical industry (medicines, plastics etc.)

- microprocessor fab and IC fabrication

- indefinitely sustained biosphere

- manufacturing industry for different high-end products, including rockets, instruments etc. and ability to maintain them.

I think you need large city with maybe 500,000 people at minimum with current technology.

Potentially science and technology, things that can be transmitted via radio. Maybe Mars could setup a hollywood style entertainment industry :)

As far as minerals, I really doubt there are any which would be cheaper to mine on mars, load on a rocket and transport back to earth, than to mine directly on earth. Even if you build a space elevator on Mars (which is much easier than building one on earth).

Maybe you could setup a 3 way trade. Even without the space elevator, it's cheaper to ship things from Mars' surface to basically anywhere in the solar system than it is from earth's surface.

So Mars could ship oxygen, water, CO2 filters, building materials, maybe even food to an asteroid station (whatever they can't source locally) and the asteroid station could ship whatever they mine from the asteroid to earth.

...No protective magnetosphere... brutal temperature shifts, and more radiation than you can reasonably survive on the way to Mars. Problems we have not solved yet...

...Or maybe we have? I see the downvotes, but no replies to explain what I missed.

> No protective magnetosphere... brutal temperature shifts

Not a problem in a shielded, climate-controlled shelter, e.g. one partly underground or in a cave.

> more radiation than you can reasonably survive on the way to Mars.

Putting food and water between space and interplanetary astronauts is a popularly-discussed option.

I think you may have been down-voted on your tone. This is an optimistic, bleeding-edge project. Unless you are an expert, it is more appropriate to ask why something isn't a problem than to prematurely declare it as unsolved or unsolvable.

I think the burden is on the person saying, "To mars, very soon!" to explain what they feel has changed, or changing, to allow that to be something other than a one-way, dead-end mission.

If you want optimism for the sake of optimism, Facebook has some lovely mother's groups.

That's an arrogant perspective. What value are you adding that anything needs to be proved to you?

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