The fact that we don't choose to live in deserts shows that it's highly likely that living in deserts - and all the more in even less hospitable environments - is not sustainable given our current way of living.
Unless we can show that we can have a working ecosystem in the least hospitable environments here on earth we aren't going to be able to set one up 4 light minutes away on a desert planet without an atmosphere. We are going to send those colonizers to a slow death.
What do you mean by sustainable? Plenty of things are capable of being done, but people happen to prefer alternatives. An example might be constructing every building in the US on stilts. It's more expensive and wastes some resources but you can still manage to run farms and cities that way.
Can we sustain a ecosystem capable of sustaining human life in a desert without atmosphere or other protection from background radiation yet then? It seems like figuring this out should be the first step.
Then again, sustainable colonies on the moon might be the most efficient way to establish that.
Unless we can show that we can have a working ecosystem in the least hospitable environments here on earth we aren't going to be able to set one up 4 light minutes away on a desert planet without an atmosphere. We are going to send those colonizers to a slow death.