The 5th Edition Dungeon Master's Guide describes the Feywild as "an alternate dimension that occupies the same cosmological space" parallel to the "Material Plane". Typically, the Feywild is described as the mirror image of a surface of a planet, for example Toril. But the Material Plane contains more than just the planetary surface: there is also the moon of Selune, other planetary bodies, and the vacuum of realmspace that surrounds them.
Is there any canonical information on what the Feywild mirror image of space is like?