Aside from mars one...
We already know how to solve the oxygen issue on the moon, it can be extracted from the moondust, there's a functional machine built that can make enough oxygen for a few people for a day with just a small amount of moon dust(like 10-20kg oxygen out of every 100kg moon dust). You could basically send an astronaut out with a shovel and they could collect enough for 10 people to breath for a week. Automate it and you could do much better.
We already know how to solve the oxygen issue on the moon, it can be extracted from the moondust, there's a functional machine built that can make enough oxygen for a few people for a day with just a small amount of moon dust(like 10-20kg oxygen out of every 100kg moon dust). You could basically send an astronaut out with a shovel and they could collect enough for 10 people to breath for a week. Automate it and you could do much better.