Lixo espacial

http://www.washingtonpost.com/blogs/wonkblog/wp/2013/10/24/space-is-filling-up-with-garbage-heres-why-we-should-tax-it/

 http://ngm.nationalgeographic.com/big-idea/12/space-trash

https://en.wikipedia.org/?title=Space_debris

http://www.space.com/16518-space-junk.html

http://www.vox.com/2015/3/9/8144825/space-maps

http://www.doorsofperception.com/infrastructure-design/eurotrash/