The question of whether there are dead bodies in space often conjures images from science fiction, where unprotected humans meet a dramatic end in the vacuum. While no deceased astronaut has ever been intentionally or accidentally jettisoned into the void, the reality involves distinct scientific and logistical considerations. Defining “space” is the first step, as it refers to the region beyond the Kármán line, the internationally recognized boundary typically set at 100 kilometers above Earth. Understanding the fate of an unprotected body and the protocols for handling fatalities helps separate sensational fiction from scientific fact.
Historical Reality: Deaths in Space vs. Orbit
A distinction must be made between dying during a space mission and dying in the vacuum of space itself. Of the 20 fatalities that have occurred during space missions, only one incident officially took place above the Kármán line. This was the tragedy of the Soviet Soyuz 11 crew in 1971, where three cosmonauts died due to rapid depressurization as their capsule prepared for re-entry, making them the only people to die in orbit. All other crew fatalities, such as those from the Challenger and Columbia disasters, occurred during ascent or re-entry, within or on the edges of Earth’s atmosphere.
The Soyuz 11 cosmonauts were found deceased inside their capsule after landing, meaning their bodies were never exposed to the external vacuum of space. While humans have died during spaceflight, no deceased person has ever been left floating in the deep void. The vast majority of mission-related fatalities happened when the spacecraft was ascending or descending, not during stable orbital flight. This history shows that while space travel is inherently risky, the specific scenario of a body floating in the deep void remains hypothetical for astronauts.
The Physics of Unprotected Exposure
Should an unprotected human body be exposed to the vacuum of space, its fate is not the instantaneous explosion often depicted in movies. The immediate threat is the lack of oxygen, causing unconsciousness within 10 to 15 seconds. The most destructive physical effect is ebullism, where near-zero atmospheric pressure causes liquids in the body, such as saliva and tissue moisture, to boil and turn to gas.
This boiling would cause the body to swell dramatically as the water vaporizes. However, the skin is elastic enough to prevent rupture, and blood within the circulatory system would not boil because the pressure maintained by the heart keeps it in a liquid state. The other major factor is temperature, which depends entirely on solar exposure; a body in direct sunlight would bake and dehydrate, while a body in shadow would flash-freeze rapidly due to radiative cooling.
Traditional decomposition, which relies on oxygen and microorganisms, would not occur. Instead, the body would be subjected to preservation processes. The combination of water vaporizing and extreme cold would result in a form of freeze-drying or mummification, leaving a highly preserved, rigid corpse. This state would be exceptionally stable, allowing the remains to drift indefinitely unless they encountered a celestial body.
Protocols for Handling Fatalities on Missions
Space agencies like NASA and ESA have developed contingency protocols for handling a crew fatality, especially concerning long-duration missions to the Moon or Mars. For missions in low Earth orbit, the body would be returned to Earth relatively quickly, often within hours or days. This quick return allows for proper forensic investigation, adherence to mortuary practices, and closure for the surviving crew and family.
A Mars mission presents a far more complex scenario, as the journey is months long and returning the body is impractical due to mass and volume constraints. The primary protocol involves preserving the remains within the spacecraft, utilizing a specialized body bag or containment unit. The habitat’s controlled environment, with its stable temperature and humidity, would slow decomposition, mitigating biohazard risks in the closed system. The remains would then be brought back to Earth at the mission’s conclusion, potentially years later.
Commercial Space Memorials and Remains
While no intact human body has been intentionally sent into space, cremated ashes have been launched repeatedly for memorial purposes. Companies like Celestis offer commercial space burials, sealing a symbolic portion of remains (typically one to seven grams) in a capsule and launching it as a secondary payload. This practice fulfills a desire for a unique memorial, sending the remains into Earth orbit, onto the lunar surface, or on a deep-space trajectory.
For orbital flights, the capsules orbit for a period before the spacecraft re-enters the Earth’s atmosphere. During re-entry, the capsule and its contents burn up completely, scattering the ashes high above the planet. Other missions have sent remains, such as those of planetary geologist Eugene Shoemaker, to the Moon’s surface, where they remain permanently.