Is it possible for governments to exile a person as punishment for their crimes? Most people will recognise the name Botany Bay for it's historical context. Botany Bay was the destination for prisoners bound for the Penal Colony established by the British in Australia. What most people do not know is that Botany Bay was not the first nor the largest. For most of the eighteenth century Britain exiled nearly 50,000 convicts to colonial America. The American revolution put an end to that and Botany Bay was established, along with penal colonies on Norfolk Island, Tasmania and in New South Wales.
Article 9 of the Universal Declaration of Human Rights includes the provision that arbitrary exile illegal. So this does not stop a nation state choosing exile as a punishment after due process. Of course, who wants a penal colony on their doorstep? This is why you do not see many people suffering exile as a punishment anymore. So what happens if the realm of the whole Solar System opens up. There will then be plenty of space for people to be exiled to who without stepping on the toes of neighbours. A penal colony on a planet without atmosphere would be very difficult to escape from.
So when we actually do go into space and start colonising Mars and other worlds will we see the return of the exile?
In the Mars Exile series of books, David Brennan was one such person sent to Mars as an exile under something called the Eaglewing Project. To avoid public discontent, government agencies involved offered this exile as an alternative to more severe punishment. David would have otherwise faced the death penalty for his alleged crime. The Eaglewing team, led by Edward Jones, sought out people who would otherwise have not received real justice, and gave them a second chance.
Will real world politics allow the same grace? Somehow I doubt it, but we can always hope that somewhere there will be an Opportunity that allows these people to show the very best of themselves.