is the most "heavenly" word; it's almost always associated with some kind of divine entity, and it's mainly used in fantasy works. is a more traditional word that is usually closer to "heaven", but it can be used as a synonym of described below.
is not strongly associated with heaven. But it typically refers to somewhere high in the sky where people still can breathe and feel the gravity. Typically [] refers to something like _Laputa_ and _Korin Tower_. If this shogunate exists in pure outer space (like _Death Star_ ), works but may not be the first choice. You may want to consider other words like , , , etc.
is a scientific term that means "celestial body", which includes stars, planets and comets. It's a well-defined term but it usually does not include human-made structures like ISS.