How close are we to cryogenic sleep for space travel?
One of the most critical problems for space travel is the enormous
distances at which objects are found. In the solar system alone,
the planets are so far away that going from one to another would take several years or
even decades while going to the closest stars would take centuries or thousands of years.
A human being cannot carry out such a long journey since we do not live that long,
so a possible solution to this problem is cryogenic sleep or induced hibernation.
This is a method in which we could put astronauts into an artificial coma, putting
them in capsules or chambers where they would remain asleep for decades or even centuries and
then wake up until they reached their destination. How possible is it to do this for modern science?
Is there cryogenic sleep for space travel? Let's find out!
According to NASA, with current technologies, it would take about seven months to reach Mars,
located at a distance of 480 million km from Earth along its orbit.
It would take a spacecraft about 8 years to reach Jupiter and 12 years to reach Pluto.
If you have ever been bored on a long-distance flight that lasted
many hours, imagine spending years waiting inside a small
spaceship to reach your destination, it would be incredibly dull, right?
How long would it take us to travel between galaxies? If we wanted to go to
the Andromeda galaxy, the closest large spiral galaxy, how long would it take?
The distance to travel is 2,537 million light years, equivalent to about 22,833,000,000
million km. If we compare this figure with the seven months needed to land on Mars,
we can see that it would take us about 28 million years to reach the Andromeda galaxy.
This figure is not exact, but it can give us an idea of the time it would take to
make intergalactic trips. Since no human can live that long and our consciousness
cannot be transplanted into another biological or artificial body, how can we solve this problem?
Many sci-fi movies, like 2001: A Space Odyssey, Interstellar, or Passengers, have already shown
us one possible option: induced cryogenic sleep, also known as Suspended Animation.
Although if we are strict, these two terms are not synonymous since cryogenic sleep implies
shallow temperatures, while "Suspended Animation" is usually achieved with only
a few degrees of reduction. However, in popular media, the terms are often used interchangeably.
Cryogenic sleep
Cryogenic sleep can be considered a kind of artificially induced human hibernation.
Various animals can lower their metabolism in nature by lowering their body temperature.
In this state of biostasis, they can spend months on limited food and water.
For example, marmots could last eight months in a hibernating state called torpor,
during which their heart rate, metabolism, and body temperature are meager. After those months,
their body warms up, and they "come back to life" without suffering harm.
Although humans cannot decide for themselves to hibernate naturally, medical technology may be
able to induce this state. Several researchers are currently studying how to make humans enter
something resembling cryosleep. From a medical standpoint, this could help treat conditions
like heart disease, diabetes, and Alzheimer's. Realistically, no technology can indefinitely
put a person into induced hibernation. The closest thing to that is an induced coma, but a coma is
not the same as a state of cryogenic sleep. The main difference is that in a coma,
the person is entirely unconscious and can't feel what's happening around him. At the same time,
their body continues to age at an average rate, in addition to their metabolism
functioning normally and needing food to not die of dehydration or malnutrition.
In contrast, in cryogenic sleep, the person enters a dream state, which is not the same
as a coma, in addition to their metabolism slowing down or almost wholly stopping,
which slows down the functions of the body and stops cell aging until they wake up again.
Then your metabolism and vital signs return to normal, and the aging process resumes.
Currently, no technology can do this, but great efforts are being made to achieve it.
An example is the cryopreservation of organs for transplantation.
In this process, the organs are cooled to low temperatures in a
cryoprotective liquid that helps prevent the formation of ice crystals and other damage.
Organs can be stored for long periods and then thawed for transplantation into a recipient.
This technique has succeeded for specific organs, such as the liver and kidneys.
Another example is the cryopreservation of human embryos and ovarian tissue. For long-term storage,
embryos and tissue are cooled to low temperatures in liquid nitrogen. Embryo cryopreservation is a
common technique in assisted fertility and has been used to preserve embryos for later use in
reproduction. Ovarian tissue cryopreservation is used to preserve fertility in women who
have received cancer treatment and may be an essential way to protect the fertility of female
astronauts during extended space travel. Examples of cryogenic preservation
Although it sounds hard to believe, some companies are dedicated to preserving frozen human bodies to
revive them in the future. These companies preserve the bodies of people who during
their lives, suffered a terminal illness and voluntarily decided that this company should
preserve their bodies with the hope that in the future, there will be a cure for their diseases.
One of these companies is Alcor Life Extension Foundation, dedicated to the cryopreservation of
whole human bodies and brains in liquid nitrogen at -196 °C. The technique is performed in a
vitrification process, which involves replacing bodily fluids with a cryoprotective solution
before immersing the body in liquid nitrogen. The goal is to minimize any damage that may occur
so that the body or brain can be revived. The Alcor Life Extension Foundation uses a
vitrification technique called "whole brain," which involves removing and replacing the
blood with a cryoprotective solution. This solution protects the brain tissues from the
formation of ice crystals, which can cause irreparable damage at the cellular level.
The body or brain is placed in a liquid nitrogen tank, where it is kept at -196°C.
Another example is the Russian company KrioRus, dedicated to the cryopreservation of human bodies
and brains. KrioRus use a similar technique. KrioRus has cryopreserved more than 80
people since its founding in 2005 and has established international agreements for
transporting and storing bodies in other countries. KrioRus is also involved in
researching and developing technologies to improve cryopreservation's effectiveness and feasibility.
As with Alcor Life Extension Foundation, cryopreservation of human bodies remains
a controversial topic and the subject of much debate, as concerns have been raised about its
feasibility and effectiveness, as well as the rights and dignity of human bodies after death.
Advantages and disadvantages Let's start with the advantages;
first of all, astronauts could travel for months or years without feeling the passage
of time in their bodies. Mental health is problematic when you spend so much time
coping with other individuals in a confined space. This also would help the number of inputs they
would require since they would need less food and water if they are asleep most of the time.
By carrying less cargo, a spacecraft would consume less fuel.
Another advantage is that cryosleep chambers could more effectively protect astronauts from
harmful cosmic radiation. On Earth, our planet's atmosphere and magnetic
shield protect us. In space, however, astronauts are exposed to radiation.
Lastly, cryosleep (compared to cryopreservation ) can be reversed relatively easily simply by
returning the astronaut to their average temperature without harming the body.
Among the disadvantages, we find the most obvious of all: this technology does not yet exist.
Second, hibernation does not entirely stop aging. With advanced technology, aging could be slowed
down significantly, perhaps even for centuries. However, cryosleep alone will unfortunately not
allow us to travel to the Andromeda galaxy. We might hibernate for a few decades or centuries,
but not for millions of years. Are there researchers trying to
get cold sleep for space travel? The answer is yes. Engineers and scientists from the aerospace
company SpaceWork Enterprises are working on a project called Torpor Inducing Transfer
Habitat For Human Stasis To Mars for NASA. It is about using a medical practice called
therapeutic hypothermia (TH), which is commonly applied in traumatic injuries.
The metabolic rate is significantly reduced by cooling the body to only
5-7 degrees Celsius. It decreases between 5% and 7% for every one °C less core body temperature.
The astronauts will go through several two-week cycles of suspended animations. During that time,
they will receive intravenous feeding, and their waste will be removed through catheters.
SpaceWorks proposes designing a torpor-inducing Mars transfer habitat and an architectural level
assessment to fully characterize the impact on Mars exploration; if this project is sustained
in the future, the technology could emerge to make the project a reality. cryogenic sleep.
Die to be reborn Many scientists have
analyzed the different options for very long trips, and more than once,
the option of taking corpses and reviving them in space has been put on the table.
Yes, just as you hear, corpses. This is the cryopreservation we talked about a moment ago. If,
in the future, we manage to develop the technology to revive bodies that have been frozen for years,
this could be the solution to long-term trips. In science fiction, cryopreservation has been
used as an effective and infallible method so that astronauts can travel for a long
time in space without feeling the effects of the passage of time.
Sadly, we still do not have this type of technology in real life.
Considering what's already being developed for cryogenic sleep, the use of this technology in
spaceflight might not be that far away. Space travel presents many difficulties.
For some of them, we haven't found a solution yet. However, if we look back,
even sailing presented several difficulties when the technology available was still in its infancy.
Space travel technology only began less than half a little over half a century ago;
we are still beginning to explore the first challenges of this long road ahead.
Beyond scientific limitations, cryogenic sleep for space travel also raises fundamental ethical
and philosophical questions about the nature of life and death and the meaning of human existence.
Yet despite these complexities, it remains an inspiring and exciting subject, inviting us
to imagine the future and dream of a world where human life can be preserved beyond present limits.
It's a bold and exciting idea that inspires scientists, researchers,
and dreamers worldwide to work together to reach new limits and
build the foundation with which we will one day travel to the stars.