Space colonisation: How near are we?

For over a century, the idea of space colonisation has pervaded both science and fiction. Also known as space settlement, or extra-terrestrial colonisation, it refers to the permanent human habitation that is not on Earth. But how far are we from this fiction becoming a reality? The truth is that space colonisation would involve such technologies as closed-loop life support systems, which have yet to be developed in any meaningful or achievable way. They would also have to deal with the as yet unknown issue of how humans would exist, behave and hopefully thrive in such places long term. As a result of the often prohibitive cost involved in sending any kind of craft or cargo from the surface of the Earth into orbit, any kind of colony in space would be a massively expensive proposition.

No space colonies have actually been built so far, nor are there any governments or large-scale private organisations with plans afoot and closed timetables for building any. However, there is no lack of ideas and discussion, of proposals, speculations and designs for space settlements. What's more, there are a considerable number of space colonisation advocates and groups and a number of high-profile scientists who argue in favour of space settlement. Reasons stated for making this enormous leap are numerous, starting with that of the first-order priority as insurance of the survival of human civilisation in the event of natural or man-made disasters. Added to this is the unsettling fact that the Sun is becoming hotter and in the distant future – we're talking 800 million years from now –  the brightening Sun will actually extinguish all life on Earth. However, a little more within our grasp is the argument that colonisation in space would afford access to the vast resources that can be found there in both materials and energy. A further argument is that of the need to mitigate the negative effects of overpopulation, to allow for expansion with fewer negative consequences for the biosphere and its inhabitants. And let's not forget the innate human drive to explore, discover and develop, which lies at the heart of progress and thriving civilisations.