The crossword solution for the term 'Heavenly Space' is 'ETHER'. ETHER is a term used in physics to describe a medium that fills all of space and transmits electromagnetic waves. It is also known as the luminiferous aether, or simply aether, and was once thought to be the substance that filled the universe. In modern science, ETHER is no longer believed to exist, but it remains an important concept in many areas of physics.