In space no one can hear you scream. It’s hard to think of a sci-fi movie where at
least one person doesn’t end up dying in space. You’ve probably seen bodies instantly freeze,
have an alien erupt out of their chest, or even explode. However,
this is not what actually happens to a body that is exposed to the vacuum of space.
And none of these movies ever discuss what happens to the body after death. Let’s use
science to find the truth about what actually happens to your body if you die in space.
Eighteen people have died in space or preparing to go into space since Yuri Gagarin first left
our planet's atmosphere on April 12, 1961. This is actually a relatively low number considering
how hostile space is to the human body. But as we plan to venture beyond our own planet,
and explore the solar system, death in space is going to become more and more common.
As of right now NASA’s official statement of what to do with a dead body if someone dies off planet
is lacking in specifics. In fact, they say: “NASA does not prepare contingency plans for all remote
risks.” Basically they’ll figure it out if it ever happens. That being said, astronauts do run
scenarios where they need to quarantine a body from the rest of the crew during space flight.
Before we dive into what would happen to a dead body that was left to endlessly float through
outer space let’s clear up some misconceptions. Movies and television shows are made to entertain.
This means the more dramatic, the better, especially when someone is exposed to the
vacuum of space. So, let’s look at the actual science and see what would actually occur
to someone’s body in space. It is pretty common in sci-fi to see someone instantly
freeze as soon as they are exposed to space. Would this really happen?
The answer is no. When you think about it, space actually doesn’t have a temperature.
Temperature is caused by the amount of matter in an area, and how quickly it is moving.
The faster atoms move, the more heat they give off, the higher the temperature is.
If there is no matter, like in the vacuum of space, there can be no temperature. There are
a lot of other things that can kill you, but you will not instantly turn into a popsicle.
Your body is around 98.6 degrees Fahrenheit on average. When exposed to space your body will
still be 98.6 degrees Fahrenhite, however, you will start to lose some of that heat eventually,
but it is not instantaneous. The reason the loss of heat is relatively slow is because of the way
heat is transferred. Normally differences between two systems—such as your body and the air outside
it—allow heat to flow from where it’s warmer to where it's cooler. Since there is very little,
to no matter in outer space, this transfer of heat can’t happen. Therefore,
your body does not instantly lose all of its heat the moment your skin is exposed to space.
However, heat can also be lost, or gained, through radiation, and since there is radiation
coming from all stars as well as from the creation of the universe during the Big Bang,
the transfer of energy through radiation does occur. For example, if you are directly in the
path of sunlight the radiation from the sun could actually make you slightly warmer for a
short time. If you are in the shadow of a planet or other celestial object your body will radiate
heat away from you and into space. The transfer of heat through radiation is slow, and therefore even
if you are thrown into space without a spacesuit, your body will not instantly lose all of its heat.
Other space deaths in the cinema depict someone exploding from extreme changes of pressure. Again,
this would not happen. There is definitely a change in pressure between the interior of
a ship and space, but that change in pressure would not result in someone exploding. However,
the lack of pressure would definitely have negative effects on a human body,
and would cause death after prolonged periods of time, but not death by explosion.
Humans, and all life on the planet, evolved under Earth’s atmospheric pressure. When there
is no pressure pushing on your body, there are negative consequences. Without Earth’s atmospheric
pressure pushing against you, the air inside your lungs, and in your veins, expands. The expansion
does not have enough force to cause your body to explode from the inside out, but it could rupture
your lungs unless it is immediately exhaled. Oftentimes in movies when the protagonist needs
to venture through space without a protective suit they are told to exhale. This is actually
sound scientific advice to keep your lungs from rupturing due to the sudden change in pressure.
A pressure change can also cause the water in your blood to convert from a liquid into a gas.
This can cause air bubbles in the blood and swelling of muscles and tissues, which can result
in an embolism. An embolism is when bubbles in the bloodstream block the flow of blood to vital
organs such as the brain. This can certainly lead to death, but cannot cause your body to explode.
A final major concern about exposing your body to the vacuum of space is that there is no oxygen,
which means death is inevitable if you do not have a space suit on that provides you
with this vital gas. When in the vacuum of space oxygen literally diffuses out of the bloodstream
and is lost to the outside environment. This leads to hypoxia, or oxygen deprivation. Within fifteen
seconds of deoxygenated blood reaching the brain you can go unconscious. Your body could survive
about a minute in an unconscious state from lack of oxygen, but soon after that you’d be dead.
This brings us to the main question. What happens to the body after someone dies
in space? It is clear that the human body cannot last long before death occurs, but
once you are dead what happens to your remains? We know that your body would not instantly freeze,
but after a while when the heat has radiated from your remains you would become a popsicle.
In terms of preservation of a body this actually is a good thing. On Earth once a living thing
dies it immediately begins to be broken down by decomposers such as bacteria. However,
in space there is no oxygen or gasses of any kind, and therefore, no decomposers can survive to break
you down. If your body is not near a source of heat such as a star, the body will freeze and stay
that way for eternity, or until you crash into something and shatter into a million tiny pieces.
On the other hand, if your dead, exposed, body is close to a source of radiation such as a star,
your remains could be cooked. If it is an intense source of radiation you would
get a really nasty radiation burn. But then again, you would already be dead,
so it probably wouldn’t bother you too much.
If you died in a spacesuit however things would be very different. Say for example you
were struck by a micrometeor. If you were able to patch the hole in the suit, but then died,
decomposition would actually start to occur right then. Your exhaled air,
and any oxygen left in the suit, would allow for decomposers to begin breaking you down.
Also, since your body is contained within the spacesuit it would take much longer for the heat
to radiate from your body, which would also allow decomposers to do their work more efficiently.
One main difference between decomposition in a space suit versus decomposition on Earth,
would be the source of the decomposers. On planet Earth there are decomposers in the environment:
like in the air, soil, water, etc. However, in space, the only decomposers are inside
your body. The bacteria that make up your microbiome would literally decompose you
from the inside out. To be fair, you aren't using your body anymore if you’re dead,
so why not let it serve as food for the microorganisms living inside of you.
The bacteria inside you decompose your body after you die on Earth as well,
but there are outside decomposers available on our planet that aren’t in space. At some point,
the bacteria would use up the remaining oxygen in the space suit and then something
really incredible happens. The bacteria move from aerobic respiration—using
oxygen to generate energy for life processes—to using anaerobic respiration.
Anaerobic respiration does not require any oxygen. One form of anaerobic respiration is fermentation,
so the bacteria in your body would actually break down your nutrients and create alcohol as
a byproduct. You wouldn’t be alive to enjoy the alcohol, but it's still pretty cool.
If there was a source of radiation from a star like the sun, it would break down your body
pretty quickly if you were directly in its path. There is also a small amount of radiation from
the remnants of the Big Bang throughout the entire universe, but it is not very much. The background
radiation would also break down the space suit eventually—although this could take thousands
of years—and at that point, any living things such as bacteria would die with you in space.
Hypothetically, if you were close enough to a source of radiation,
and the space suit broke down while there were gasses in it from the decomposition of your body,
something really crazy would happen. The processes of respiration and fermentation
create gasses such as carbon dioxide as a byproduct. This means the bacteria would
be filling the space suit with gas and increasing the pressure within it
while breaking down your body. If the space suit was suddenly compromised by a tear or radiation,
the result could be a small explosion. The space suit would tear apart releasing all of the gasses
at once in a silent explosion; since sound waves can’t be created in the vacuum of space
Something that has come up recently as NASA and other space agencies prepare to launch
manned missions to Mars and beyond is what to do with the body of an astronaut who has died
on a mission. There is no set plan yet, but it has been discussed because as humans venture
further and further from the protective shield of Earth, accidents are bound to happen. People
will die in space at some point, so what would the other astronauts do with the body itself?
On a space station or ship there is air for the crew to breathe. This means that there is oxygen,
and therefore, decomposition of a dead body will occur. The body needs to be sealed away somewhere
quickly because it will begin to smell. There is also the problem of the body being a biohazard.
A bunch of nasty pathogens can be passed on from one human to another while handling a dead body,
and the longer a corpse is allowed to decompose, the worse things can get.
There are a couple of contingency plans that have been thought up by space agencies if an
astronaut dies in their spacesuit. It would make the most sense to keep them in the spacesuit,
and trap the gasses of the dead body within. The suits themselves are self contained,
and nothing would be able to get in, or more importantly out. Once the body is
secured it would then be moved to one of the colder parts of the spacecraft. This might
be near one of the airlocks, but it should definitely be away from the rest of the crew.
Other options of what to do with a dead body in space could be to send it back to Earth
on a resupply ship. Or jettison the body and let it burn up in the atmosphere of whatever
the closest planet is. For example, both Mars and Venus have atmospheres that could
be used as a means of cremating a body on re-entry if Earth is too far away. However,
if the body needs to be preserved and returned to a planet so that it can be buried,
there are ways to keep a body along for the ride without keeping it inside the spaceship.
One method of dealing with a dead body during a long space mission
is to mount it on the outside of the spacecraft. If kept on the side of the
ship facing away from sunlight, the dead body would eventually become freeze dried.
Then the crew could choose from a few different ways of disposing of it.
Once the body is frozen it could be released from the ship and sent on a trajectory to be
incinerated in a nearby star. Or the path chosen might allow the corpse to float endlessly through
space. If the explorers don’t want to litter space with human debris they could wait until
the body is completely frozen and then use a robotic arm to smash it into small,
crystallized, pieces. This may seem gruesome, but it would cause the body to break up into minuscule
fragments, which would eventually burn up in an atmosphere or be broken down by radiation.
Humans are on the verge of venturing out of near Earth orbit and heading to other planets
and beyond. It is a fact of life that everyone dies, and as more and more people travel to space,
this natural process will occur beyond our planet. You won’t explode if exposed
to the vacuum of space, but you will eventually freeze, leaving your body
destined to float around the universe for eternity, or until you crash into something.
Now check out “What Happens to Your Body After You Die?”
Or watch “What Happens To Your Body in a Coma?”