What are the rules regarding the founding of colonies on Mars? If Elon Musk decided to build a colony or city on Mars, would he need anyone’s permission first? If not, and he built a colony, would he be able to lay claim to ownership of the planet, or perhaps to some defined area of it? What if he were to declare his colony to be a sovereign state with its own laws?
The Outer Space Treaty (to which the US is a signatory) forbids any signatory country from claiming jurisdiction over any part of a celestial body.
Of course, there’s space law and then there’s space practicality. If someone really wants to establish a colony on Mars and install their own government there, and they have the capability to do so, it would be difficult to send the space cops over there to stop them.
You want to own mars? No problem! Just send me $10 million and ill send you a deed.
Hey! The guy I bought Mars from charged me $15 million. I think I got ripped off. The joke’s on him though. I paid him in Bitcoins. 
Mars is owned by the Mars family.
And if someone else wanted to found a colony, the first colony probably couldn’t do much to stop them.
Anyone who was capable of planting a colony on Mars right now would be so far ahead of any other space program in the world that they probably could stop anyone else from founding a colony.
Folks talk a lot about international law, but what most of it really boils down to is “whatever you have the power to get away with”.
… but we all know they’d try … just human nature to fight …
Depends on what the first colony has in the way of equipment, I guess. Assuming the two are not cooperating, the second could and probably will be thousands of kilometers away from #1. Just travelling from one to the other is likely to be well beyond the capabilities of either. A missile would do the trick, but is it likely anyone would equip a colony with an ICBM?
But it’s likely they would have Terran assets available, if a government wanted to get nasty.
But it would not necessarily be a case of sending the cops to Mars, more that other countries could take action against the aggressors here on earth.
Sanctions between the relevant countries for example, or governments pursuing the relevant corporations.
Yes, of course they would. What do you think an ICBM is?
If you have the capability to get from Earth to Mars, then you also have the capability to get from one point on Mars to any other point on Mars, as the latter problem is many orders of magnitude easier than the former.
The Outer Space Treaty also covers planetary protection, i.e. preventing biological contamination. A manned mission would have a very hard time meeting planetary protection protocols for Mars, let alone a permanent settlement.
Although I don’t know if there are any enforcement mechanisms for it, beyond political pressure (sanctions, etc). Presumably the FAA could deny launch permission for a colony ship for not demonstrating compliance with planetary protection protocols?
Fairly recently, I learned that the Pilgrims mounted a cannon over their settlement. I always wondered what it was for. If the Indians attacked in force, they’d get a few shots off, but the colony was so small, even if they repelled an attack, the victory would have been Pyrrhic. Were they trying to defend against Pirates? The French? If a single French fishing boat came, and they asked it to leave, and it didn’t – would they then sink it? What if a Spanish or French or Dutch (depending in the exact politics at the time, which no one could really communicate rapidly) cam in force vs their one hilltop mounted cannon?
But yeah. The new colony needs defense. And as was said, the appropriate technology obviously exists, if you can try to colonize at all.
I’ve heard it argued that the whole point of manned missions into space was to field test ICBM technologies … without starting a war …
I need a cite on this, because it’s very hard to believe. The U.S. and U.S.S.R. were doing fine testing ICBMs before the space program. Satellites were launched by modified versions of the ICBM, like the Russian R-7 for Sputnik, not the other way around. Any working test of a rocket brought useful information, obviously, but that’s not what you’re saying.
I think it was more a matter of showing off one’s missile technology, rather than testing it, per se. Which has historically also been the purpose of most nuclear bomb “tests”.
You could not use an ICBM on Mars, because Mars has no continents.
Ships used cannon as signals. Perhaps settlements did, too. Like a church bell.
Dime store sci-fi novel here : if a large and well supplied colony were present, and another upstart colony had just landed elsewhere on the planet, all the large colony would have to do is fuel up an extra mars ascent vehicle (MAV) and send it to go crash into the coordinates of the upstart colony.
Obviously the MAV has pinpoint landing accuracy, and you could just have it set for a “goal” of X,Y,Z with a velocity of 1 kilometer/second downwards basically.
Might take a little computer modding and or mission planning, since this would be outside the vehicle’s design parameters, but totally doable. Similarly you could rig up a fuel-air explosive where you premix liquid methane and liquid oxygen right before impact.
Though a sci-fi novel wouldn’t have that as the solution. Why destroy a colony when you can steal their stuff? So instead you’d send the MAV to go land and drop militia armed with guns to capture the colony.
The usual kill the disposable men/capture the women and highly skilled men thing primates have been doing for millenia.