I have never heard of space music. Although it may be good to go sleep with, I do not really think it is my cup of tea.
I googled Wikipedia just to see where it came from and here is a snippit of its description.
Since I am probably lacking in some sub genre I may have to start taking a look at what is out there. 
Space music , also called spacemusic , is a subgenre of new-age music and is described as “tranquil, hypnotic and moving”. It is derived from ambient music and is associated with lounge music, easy listening, and elevator music.[3]
According to Stephen Hill, co-founder of a radio show called Hearts of Space, the term is used to describe music that evokes a feeling of contemplative spaciousness.[4][5][6] Hill states that space music can range in character, the sonic texture of the music can be simple or complex, it can be instrumental or electronic, it may lack conventional melodic, harmonic, or rhythmic features, and may be less concerned with the formal compositional schemes associated with other styles of music.[7][8] Hill proposes that space music can be found within a wide range of genres.[7][9] Space music may have influences from western classical, world, Celtic, traditional and experimental music
