Cremation holds a controversial place within the beliefs of Astronism and its study in relation to Astronism is categorised as part of the discipline of mortology. Much of Astronist funerary tradition is based on and geared towards the belief in cosmosis which, depending on the school of thought, is a physical reunion between humans and The Cosmos. It is believed in Astronism that all people undergo this process as part of the natural process of decomposition.

However, the practice of cremation does not allow for the process of decomposition to occur and therefore has been interpreted as being contrary to the beliefs and particularly the ultimation of Astronism which is cosmosis.

Alternatively, some Astronists have interpreted cremation as in alignment with the belief of cosmosis. This is manifested in the belief that cremation is actually a quicker way to become unionised with The Cosmos.