Cryogenic Sleep For Space Travel

Why we (might) need cryogenic sleep

A big problem connected to space travel is speed and distance. Since planets are so far away from each other, it may take years, even centuries, to get there. Let’s consider interstellar space travel within our solar system. According to NASA, on average and with the current technologies, it would take us about 7 months to get to Mars, when it’s placed at a distance of 480 million km from Earth along its orbit. We would need around 6 years to get to Jupiter and 9.5 years to get to Pluto. If you have ever gotten bored on a long-haul flight, imagine spending years waiting inside a spacecraft.

Cryogenic sleep: pros and cons

Cryogenic sleep can be seen as a sort of artificially-induced human hibernation. In nature, there are several animals that can reduce their metabolism by reducing the temperature of their bodies. In this state they can go on for months with limited food and water. To give an example, ground squirrels spend 8 month in a hibernation state called torpor, during which their heart rate, metabolism, and body temperature are incredibly low. After these months, their body warms up and they “come back to life” without any damage. While humans can’t naturally decide to hibernate themselves, it might be technically possible. Several researchers are currently studying how to put humans into something similar to cryosleep. From a medical point of view, this could help treat diseases such as heart disease, diabetes and Alzheimer.

But what are the pros of cryogenic sleep for space travel?

  • First of all, astronauts would be able to travel for months without noticing it. Mental health is indeed a problem when having to spend so much time locked inside a very small space with other individuals.
  • Additionally, they would need way less food and water. By carrying less cargo, the ship would use less fuel.
  • The cryosleep chambers could protect astronauts more efficiently from harmful cosmic radiation. While on Earth, its atmosphere and magnetic shield protect us. In space, astronauts are exposed to radiation.
  • The chambers could have an artificial Earth-like gravitational force that would keep astronauts’ bodies in shape. In fact, because of the lack of gravity, astronauts have to fight against muscle atrophy or bone degeneration by exercising on average two hours per day. The technology necessary to produce artificial gravity in a space as wide as a spacecraft would be extremely complex and expensive. On the other hand, cryosleep chambers are small in size and studies are underway to make gravity possible inside them.
  • Finally, cryosleep (compared to cryopreservation) can be reverted relatively easily, by simply bringing the body back to its normal temperature, without damage to the body.

What are the cons instead?

  • The first one is that this technique hasn’t been successfully perfected yet.
  • Secondly, hibernation doesn’t completely stop aging. The metabolic reduction achieved through the use of low temperatures slows down the aging process. With advanced technology, aging could be significantly slowed down, maybe even for centuries. Yet, cryosleep alone will unfortunately not allow us to travel to the Andromeda Galaxy.

Cryopreservation for space travel

If we want to eventually reach extragalactic planets, cryopreservation may be the solution we are looking for. Cryopreservation is a procedure the body undergoes after legal death that allows it to be preserved for as long as it’s needed through the use of very low temperatures (-196 °C). In fact, through vitrification, all biological processes stop. The astronauts could be preserved even up to 28.000 years, without virtually any change or degradation.

Current cryosleep research

Are there actually any researches trying to achieve cryosleep for space travel? The answer is yes. Engineers and scientists at the aerospace company SpaceWork Enterprises are working on a project called Torpor Inducing Transfer Habitat For Human Stasis To Mars for NASA.


Considering what is already being developed for cryogenic sleep, this technology being used in space flight might not be so far away. Certainly, there are still many problems to be solved. Space travel presents many difficulties. For some of them, we still haven’t found a solution. But if we look back to the past, even sailing presented a number of difficulties when the technology available to us was still in its infancy.



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