He had read the 1967 United Nations Outer Space Treaty, which prevents countries from claiming celestial bodies as their territory. He declared the moon his property, divided it into parcels and began selling certificates to customers around the world. The moon presented a rather different possibility.During his university years, Hope had encountered the 1967 United Nations Outer Space Treaty. They were buying certificates based on Hope's claimed ownership system.Hope's prices were designed to make lunar ownership accessible to ordinary customers. Reportedly, Hope said he had sold more than 611 million acres of lunar land.