Some of these concerns are valid (in particular the microbiome and the possibility and probability of unforeseen variables) but others are not.
Even assuming that we can't use mirror arrays to use natural lighting within habitats like O'Neil envisioned, there is nothing about sunlight that we cannot replicate with artificial lighting. In fact, we could make a safer substitute that forgoes the ultraviolet radiation.
It also doesn't take that much radiation shielding to do a better job of protecting us against cosmic radiation than the Earth does. While there is 100 KM of atmosphere between us and the vacuum, that is air and of a density that drops sharply with altitude. We could easily match and exceed that protection with plating of about 20 metres.
The reason why radiation is such a concern in space travel at the moment is because current launch costs prevents any but the most spartan kinds of shielding from being economically viable. Once we can construct launch assist devices like rotavators and orbital rings, that is not going to be a major limitation anymore.
Even assuming that we can't use mirror arrays to use natural lighting within habitats like O'Neil envisioned, there is nothing about sunlight that we cannot replicate with artificial lighting. In fact, we could make a safer substitute that forgoes the ultraviolet radiation.
It also doesn't take that much radiation shielding to do a better job of protecting us against cosmic radiation than the Earth does. While there is 100 KM of atmosphere between us and the vacuum, that is air and of a density that drops sharply with altitude. We could easily match and exceed that protection with plating of about 20 metres.
The reason why radiation is such a concern in space travel at the moment is because current launch costs prevents any but the most spartan kinds of shielding from being economically viable. Once we can construct launch assist devices like rotavators and orbital rings, that is not going to be a major limitation anymore.