Transtellationism, also referred to as astranthropism, astranthropy or the transtellationist school, is one of three major branches within Millettic eschatology and thanatology characterised by its affirmed belief in supernatural occurrences upon one's death with some involvement of cosmic progeny and phenomena. As suggested by the school's appellation, the most prominent of such beliefs is the occurrence of the process of transtellation upon one's corporeal passing. However, this represents just one of many Astronic supernatural beliefs regarding death and the end times. The transtellationist school is therefore defined from the other two Astronist branches of thought in this area, naturalism and transcensionism, by focusing on supernaturalism for the foundations of its eschatological and thanatological beliefs.

Transtellation

The belief in the occurrence of the transmigration of one's soul to the stars upon one's death is the most prominent of all the supernatural beliefs within Astronism regarding death and the afterlife. Transtellation may be considered as a form of cosmosis, or "becoming one with The Cosmos" upon one's death and involves both a physical and spiritual ascension to the progeny and phenomena of The Cosmos. Therefore, unlike the other forms of Astronic eschatology, the existence of a soul is postulated in the transtellationist position for its beliefs are dependent upon the existence of a soul in each and every sentient being.

However, despite their affirmation of this process of stellar transmigration upon a person's death, transtellationists do not generally consider there to be any further afterlife after the process of transtellation has occurred which differs from other religions and philosophies which state an extensive afterlife or union with some form of divinity. The latter point, however, is considered to be completed via the transtellation process for when a person's soul becomes one with The Cosmos, this is considered to be a form of divine union. Furthermore, there are various debates being held in the Astronist community regarding whether non-sentient beings have souls too and whether these souls hold the ability to transtellate as sentient being's souls do.