If someone dies in low-Earth orbit (such as on the ISS), their body could be returned to Earth within hours on a returning capsule.
If death occurred on the Moon, the body could be returned in a few days using existing NASA protocols. Preservation would likely not be a major concern in these quick-return scenarios.
For long-duration missions like a trip to Mars, the body would need to be preserved onboard until the crew completes their mission and returns to Earth, which could take years. It would likely be sealed in a specialized body bag.
Exposure to the vacuum of space or a planet’s atmosphere like Mars would cause almost instant death due to lack of pressure and boiling of fluids.
Cremation is not desirable on distant missions due to energy needs, and burial risks contaminating other worlds. Returning preserved remains to Earth is preferable.
Psychological support for surviving crew and grieving families back on Earth would also need to be considered in addition to handling remains. Planning is needed as space exploration moves toward potential human colonies.
SOURCE: The Conversation