The astronaut is auctioning off his moon-landing jacket and other space gear
Auction house Bonhams is expecting around $1 million
Online Christie's sale features 2,400 photographs from "the golden age of space exploration"
Experts call on spacefaring nations to protect lunar landing sites, not to mention Neil Armstrong’s footprints
The Apollo 11 astronaut who walked on the moon dreams of a future where Americans are the first to walk on Mars