What is more difficult, a self-sustaining colony on Mars or the Moon, or a permanent O'Neill habitat in Earth orbit?

I think the moon has little or no advantage over the past few months. Not only is it useless, except that there may be a little ice in the pole, there is hardly anything at the bottom of a quite gravity well. One day? of course. But for those who are trying to raise it as rocket fuel, ice will be used more for migrants of the moon.

More ice can be taken from asteroids carried to the lunar orbit station. And it is an ideal place to work. Later, asteroids can offer valuable items from iron to platinum and gold. Yes, these methods may (perhaps) be the basis for building space colonies

I am not a fanatic fan of Mars. But if this is the goal, you should investigate Phobos and Deimos to see if you can harvest similar resources there and make traveling from Mars more economical. It is essential to acquire Mars ice automatically and convert it to useful water and fuel. We are researching these technologies at NASA NIAC

As its launch vehicle and crew mature, NASA plans to move its outer space from low Earth orbits to clockwise activity. These may include orbits of the moon and tests on the Earth - Moon Lagrange 's universe habitat where astronauts can practice 200 - day Mars transport. The US will not have its own space beyond the promotion of low Earth orbit. China launched the second orbital research institute in 2016 and plans to construct a permanent space station in 2022 and hopes to send the astronaut to the moon by 2036. India has the ambition to fly humans there, but its first manned space flight is expected to be 2021 years ago.

Let's imagine the universe colony in our solar system It is really a self-sufficient habitat Hundreds of thousands, millions of people continue to live beyond the earth. The moon and Mars are unlikely to be candidates for these colonies. Their low gravity can adversely affect health. For discussion, let us assume that the advanced colonies we imagined were on Venus after being successfully transformed. Venus' colony found a viable regional governance approach, and the diversified form of colonizers was combined with the planetary management agency 21, prospering with the planet, peaceful and mutual I am enjoying a useful relationship. But at some point the residents of Venus decided that they wanted more than just semi - autonomous rule: they wanted full autonomy and independence. They want to leave the earth. So what?