Spaceflight is like backpacking. If you can’t restock supplies like food and water along the way, how far you can travel is limited by how much you can carry. And in space, you also have to worry about having enough fuel for your spacecraft and breathable air for your crew.
Read the entire article here:
http://www.astronomy.com/news/2018/07/using-sunlight-to-make-spaceship-fuel-and-breathable-air
