I can't really find where your line for "space travel" is. Humans on earth need resupply from other parts of earth, the bases on Antarctica are about equally as

I can't really find where your line for "space travel" is. Humans on earth need resupply from other parts of earth, the bases on Antarctica are about equally as unhospitable towards humans, not to mention cruise ships where some people live aboard for years at a time. Heck, my own house is an unsustainable habitat that requires constant resupply.