The issue is how to finance it. Take the blinders off. Mars has a massless solution... Sell mars.
Now who owns mars? Nobody. So nobody can sell it. Government would tell you they do since government is always taking by force what isn't theirs.
Who would be putting their lives on the line for humanity? Those 200,000 people. Let them sell mars!
Give 144,000 of them a one thousand square kilometer claim by lottery (that's the entire surface area of mars.) That's one billion square meters to each. If it costs $150m per colonist (my estimate) to send them (in quantity) that's 15 cents per square meter. Hold the money in trust so it can only be spent on transport and supplies. The top contenders will see their property sold first.
This is like an X-prize that pays 100% of costs.
BTW, this does not mean colonists would live thousands of kilometers apart. They would live together simply by trading property with each other.
The only justification needed to go to mars is people want to go as long as they don't require that you pay for it. So let them pay for it themselves.
To speed up the process, allow those with money in their trust to give that money and unsold property to another contender in order to receive one percent of their money in the trust.
Set the price at 25 cents per square meter in case my estimate ($150m per) can't be met. Mars One wants a reality show? This will give them a reality show. Allowing some to give their trust to others means whatever the actual cost will be, will be met.
2000m2 for $500 would be a suggested plot size, but any number of square meters could be sold at a time. Grandparents could buy 200m2 for $50 to give to their grandkids.
Property rights should be absolute, no property taxes, no eminent domain, no regulations that take value from property. No government telling people that came from every country on earth what they must do.
Update: 1058 hopefuls have been selected as candidates to begin human life on Mars in 2025.
So we give these the first lottery round. The rest go into a second lottery round.
Update 2: Is this legal? The martians who are on mars will make it legal. Laws are made by those that can enforce them.
Update: To address an excellent question. JamesG asks...
Who's to say that after making your investment, someone else (say... the Chinese) who conveniently don't accept extraterrestrial territorial claims, won't steal the tech and jump your claim? Or worse yet (from a litigative perspective), some person who bought an obscure novelty "property deed on Mars" won't sue you for everything you're worth on Earth for violating their claim?First we need to understand the basics of property rights right here on earth.
The most fundamental way property is owned is by a willingness to defend it. But beyond that all property is owned by agreement to convention so that pieces of paper prevent the need to get out your shotgun. This is called chain of title. All chain of title begins with a claim. Then it's bought and sold with the last person to buy having ownership which is verified by a title search. Any property owned by anyone anywhere adheres to this convention.
What about those pesky chinese land grabbers? Is this supposed to be some unique gotcha scenario that invalidates the plan to colonize based on money for tickets held in trust? Sorry it's not unique and doesn't. In the adult world we recognize that all investments have risks. The chinese or anyone else could grab land on mars by sending some there to possess it. Nothing but a willingness to do so prevents it. Because it would be by physical possession it likely they will have the stronger claim.
Who in that case is at risk? The person that bought land where the chinese grabbed obviously. That would be a known risk that the person buying land would have to consider. It really doesn't affect the plan at all. That risk is very small because mars has 14.4 billion hectares and those most purchased are going to be where they are being possessed by those that would enforce those claims.
What about novelty deed law suits? Really? This seems like a real problem? The good news is they've already been tested in court, or rather, the court has already decided they aren't even worth considering. So let them sue. Anyone that imagines they will have any standing has a peculiar view of law. But again, the risk is on the purchaser. They can find out if anyone has a novelty deed and simply avoid purchasing land in conflict until after it's determined in court that those novelty deeds have no value.