Space is a hazardous and harsh environment. It will only be a matter of time before regular people are exposed to this environment, either through space tourism or by joining self-sustaining colonies far from Earth. To that goal, a deeper knowledge of how the environmental risks of space will affect the biology of human cells, tissues, organs, and cognition is required. We need to know whether we can easily reproduce in environments other than those found on Earth in order to plan future space colonies. The effects of radiation on our cells, which cause DNA damage, have been thoroughly studied. What is less obvious is how reduced levels of gravity, known as microgravity by scientists, would influence the mechanisms and cycles that occur within our cells.
Scientists are only now beginning to examine how exposure to microgravity may impact cell function. Experiments on embryonic stem cells, as well as simulations of how embryos develop in their first few weeks in space, will help us establish if humans can create kids in future extraplanetary settlements. A few creatures, including insects, amphibians, fish, reptiles, birds, and rodents, have been tested for their potential to breed in space. They discovered that species such as fish, frogs, and geckos may create fertilized eggs capable of living and reproducing on Earth during spaceflight. In mammals, however, the picture is more convoluted. A study of mice, for example, discovered that exposure to microgravity disturbed their estrous cycle, which is part of the reproductive cycle. Another study discovered that exposing rats to microgravity induced harmful neurological changes. These impacts might theoretically be passed on to future generations.
This is most likely due to the fact that our cells did not adapt to function in microgravity. They developed on Earth over millions of years in its peculiar gravitational field. The gravity of the Earth is part of what anchors and exerts a physical force on our tissues, cells, and intracellular contents, assisting in the regulation of particular motions within cells. Mechanobiology is the study of this. The division of cells and the movement of genes and chromosomes inside them, which is critical to fetal development, also operate with and against gravity as we know it on Earth. As a result, systems that have evolved to function properly under Earth's gravity may be impacted when the force of gravity changes.
It is also feasible to generate pluripotent human stem cells from our bodies' regular mature cells, which are known as induced pluripotent stem cells (opens in new tab). These have also been researched in microgravity, with trials on Earth revealing that induced stem cells grow quicker in simulated microgravity). Two batches of these stem cells are presently on the International Space Station to see if the findings can be repeated in space. Because it is difficult to develop enough stem cells on Earth to cure degenerative illnesses with stem cell treatments, if adult stem cells multiply quicker in space, it might pave the way for commercial stem cell manufacturers to create these cells in orbit.
Aside from regular cellular operations, it's unknown how microgravity will affect fertilization, hormone synthesis, breastfeeding, and even birth itself. It appears that brief exposure to microgravity, possibly for half an hour, will have no effect on our cells. Longer exposures of days or weeks, on the other hand, are likely to have an effect. This does not account for the effect of radiation on our cells and DNA, but we already know how to protect ourselves against radiation.
Scientists are investigating two approaches to combating the negative effects of microgravity on our biology: intervention at the cellular level via pharmaceuticals or nanotechnology, and intervention at the environmental level via replicating Earth's gravity in spaceships or off-world settlements. Both disciplines of research are in their infancy. Nonetheless, researching stem cells in space gives a crucial window into how pregnancy may or may not happen when we are beyond the gravitational sphere of Earth. For the time being, people who are lucky enough to travel to space should avoid trying to conceive before, during, or immediately after a space voyage.