The ideal conditions for human life are between 30% and 60% reality. Below that, shapes become unconstant. You become larger and smaller based on your mood and feelings. You hands distort. Space and time bends. 

Earth is in the "Goldilocks Zone", with truth levels that are perfect for human life. Any higher and humans would never have been able to become sentient. Any lower and human life would never be able to become organised into human shape - we would exist as scattered shapes and strange resonances.

Haunted Houses. Empty Sewers. Abandoned amusement parks. These are the Low Reality Zones. Away from human influence, they warp and bend and grow carnivorous. The further you get from human culture, the more strange you become. Your body and your mind slowly expands and mutates and fractures in on itself. 

So you can see why the space program was a failure.