Settlements on Mars are hot-button issues. As humanity imagines our future in space, many believe that technological developments and scientific discoveries will pave the way for future settlements. Human birth in space -- one of the main goals of Asgardia -- is the next logical step in science
The countdown is on: it is possible that the first child will be born outside planet Earth in just five years. In 2024, the technology company SpaceLife Origin plans to send a pregnant woman to 250 miles above Earth where she will give birth to the first space baby during a 24- to 36-hour mission under the supervision of a team of medical experts. Before embarking on such a groundbreaking project, the Netherlands-based firm has set the goal of engineer the Ark, an incubator for `human germ cells that will protect the “seeds of life” from radiation, heat and other space effects. It is scheduled to launch into orbit in 2020.
In 2021, the company will embark upon the Lotus mission, in which an orbital extracorporeal fertilization will occur, and after four days the embryo will be returned to Earth and implanted in a woman who will bear the "space" child.
Human birth in space is the next logical step in science, made possible by numerous experiments that have been conducted not only on protozoa, algae, insects, salamanders and birds, but also on mammals.
How chlorella gave birth, and peas overcame weightlessness
Even before sending a man into space, genetic scientists had wondered how space conditions would have affected cosmonaut cells. Therefore, microorganisms, plant seeds, fruit flies, mice and dogs first flew into orbit to test the effects of weightlessness, radiation, vibrations and acceleration on heredity. No significant changes in the genetic information of the DNA occurred during short flights. The next logical step, which seemed safe, was to send a human next.
If genes were not damaged by radiation and did not change in weightlessness, then is the process of reproduction possible under the conditions in space? To answer this question, scientists began to conduct experiments with unicellular algae, and then switched to plants.
In 1978, the “space algae” Chlorella was delivered to the Salyut-6 scientific orbital complex to conduct the experiment of the same name in order to study the effect of weightlessness on the growth of the algae population. The unicellular organism received its name due to properties useful to astronauts: chlorella absorbs carbon dioxide and produces oxygen, contains a lot of protein, making it a nutritious product, and also multiplies rapidly.
The experiment began with four containers with seaweed in a "dormant" state sealed in vials delivered to Salyut-6. In each of three containers, one tube with chlorella was crushed, thus dropping it on a nutrient medium. The remaining vials were returned to Earth in an inactive state in order to study how a short flight had affected the organisms. On Earth, in laboratory conditions without weightlessness, chlorella was sown as control group simultaneously with the orbital seeding. The fourth container contained vials with different types of algae, which were also planted in a nutrient medium in order to study the manifestation of competition between them under the influence of various cosmic issues.
Malyshka, one of the first dogs to be rocketed into the atmosphere, poses with her spacesuit
The significance of the experiment was in that the structure of the eukaryotic cell of chlorella is similar to the cells of higher plants and all animals. Therefore, further experiments with the breeding of "cosmic" organisms depended on the result of this mission. The experiment found no fundamental differences between the populations of orbital algae and algae grown on Earth. Researchers also found that microgravity has no effect on the algae growth rate: the chlorella population grew as fast as that on Earth.
The outcome of the Chlorella mission allowed geneticists to proceed to experiments on higher plants. Aboard the Soyuz-19, cosmonauts began to study the influence of cosmic factors on the development of the flowering plants of Crepeza and Arabidopsis, observing the appearance of their seeds and their subsequent germination. When the new plants reached “adult” size, they were fixed so as to avoid damage during flight, and returned to Earth.
In the laboratory, scientists compared the course of development of "cosmic" organisms with the control Earth variants for the "breakdowns" of the hereditary apparatus of the cell. Studies demonstrated that cosmic factors, especially radiation, have contributed to a statistically significant increase in chromosomal abnormalities, as well as disruption of normal cell division.
The experiment of Peter Klimuk with the germination of pea seeds also showed that cell division in space is different from the same on Earth. After swelling, the seeds were released not into the soil, but into air. However, the need for obtaining nutrients forced the roots to lower into soil.
Thus, studies on the reproduction and growth of plants demonstrated that microgravity and radiation might change the usual course of their development. However, the reproduction did not stop. What did that mean for more complex organisms?
How cosmic flies became the favorite subjects of scientists, and fish were lost in space
Tiny fruit flies, which in their biochemical mechanisms are similar to many animals, including humans, were also sent to space. -, as evidenced by a much larger number of deferred larvae.
The flies also underwent genetic changes: the gene responsible for the chitinous membrane was modified. But after returning to Earth in 12 hours, their body fully recovered, which indicates the adaptability of terrestrial organisms in different conditions.
Four generations of the Drosophila melanogaster appeared in orbit, and scientists noticed that the flies multiplied much more actively than on Earth. Photo credit: NASA
Changes also occurred with the newborn zebra fish Danio rerio, which was sent to the Soyuz-16. Scientists investigated how cell division proceeds, as well of the development of fry, and found out that microgravity impacted their vestibular apparatus: the fry in space did not distinguish between top and bottom, while on Earth these criteria form the basis of their orientation in space.
How the egg beat the chicken
Next, amphibians – namely salamander eggs – were sent into orbit. Two experiments were carried out on the Mir space station with the eggs of these cold-blooded vertebrates, which were fertilized and grown under weightless conditions until hatching.
Evidence confirmed that microgravity conditions affected the embryonic period, especially during cleavage and neurulation, causing irregular segmentation and abnormal neural tube closure. But all of these changes were temporary, and subsequently, the young larvae that hatched during the flight had a normal morphology and were able to swim after landing, once again proving the ability of organisms to adapt to environmental changes.
Compact quail eggs – more specifically, quail embryogenesis – has also become the subject of research by scientists. Quails were chosen for their high nutritional value, so they can be included in the composition of biotechnical life support systems for astronauts, and also because they are small and unpretentious, easy to deliver into orbit and. It is also easy to observe their embryonic development, because they develop in the eggs, not in the mother's womb.
The astronauts “hatched” a few quails, which did not differ from their earthly counterparts. However, when chicks had to find support and stand up to move, they began to tumble. After ten hours of such unusual movement, complete atrophy of instincts occurred in newborn birds: they did not react to light and sound. Another part of the chicks simply could not find the way out the eggs, unable to pierce the shell.
How "space" rats paved the way for the possible future emergence of a human "space" newborn
Reproduction of mammals is much more complicated than that of plants, insects, fish, amphibians and birds. The fact is that oocytes do not have sufficient resources to support full development, and, therefore, after fertilization, the embryo must be implanted in the uterus to receive nutrients from the mother through the placenta. Thus, in order to proceed to studying the influence of various cosmic factors on mammalian embryogenesis, scientists first decided to test how radiation and weightlessness can affect the germ cells of animals.
Sperm samples of mice were sent to space. The experimental data showed that zero gravity affected the sperm cells so that all indicators were increased. Russian scientists also revealed some anomalies of spermatogenesis of Veterok and Ugolok dogs, when samples of their biomaterials returned from orbit to Earth. The experiment with bulls' spermatozoa sent into space confirmed once again that microgravity is having an effect: the germ cells in space moved twice as fast and changed the curve of their movement.
The study of mammalian embryogenesis began with the mouse sperm was sent to space for nine months, which was then returned to Earth and used to fertilize females. As the result, healthy mice were born. The weightlessness did not play a big role, the scientists concluded. But what is known about the effects of cosmic radiation on mammalian germ cells and embryos?
A lab experiment was conducted on Earth to determine the effect of radiation on the development of primate embryos. It showed that even relatively low doses of ionizing radiation are enough to kill most immature oocytes in a female fetus in the second half of pregnancy. Scientists suggested that it is likely that a female conceived in space may be born sterile due to damage to her germ cells. Thus, it became obvious that radiation is a factor that can stop the process of cosmic reproduction even more so than weightlessness.
A lab experiment was conducted on Earth to determine the effect of radiation on the development of primate embryos. Photo credit: US Air Force
After the influence of cosmic conditions was tested on the germ cells of animals, scientists decided that it was necessary to carry out “cosmic” fertilization. Japanese researchers conducted an experiment with in vitro fertilization using a three-dimensional clinostat to weaken the effect of microgravity.
The procedure was successful, but when the zygotes were transferred into mice, the number of pups produced was lower than in the control group on Earth. Therefore, scientists have concluded that fertilization can take place under conditions of weightlessness, but normal preimplantation of the embryo may require terrestrial conditions.
Then, it was decided to test how the space conditions would affect the emerging embryos, which, after landing, would be transferred into mice. Onboard the Space shuttle Columbia STS-80, two- and eight-cell mouse embryos were sent into orbit, which were grown in a culture for four days. Unlike the salamander egg experiment, in which neurulation changes were temporary and reversible, scientists discovered that upon return to Earth, the embryos that had survived the flight stopped growing at the development stage of the neural tube, unlike the control embryos, the growth of which proceeded without deviations.
A more reliable experiment was carried out on the Cosmos 1129 mission, when mature rats, both male and female, were sent into orbit and allowed to mate in a common chamber. However, none of the females subsequently gave birth, although post-flight studies showed that ovulation had occurred. Scientists reported on the pregnancy of two females, but the embryos appear to have been resorbed.
The next experiment sent the first pregnant rat to space. The researchers noticed that space travel had a greater impact on the mother than on the young: she lost a quarter of her weight, and her hormonal and endocrine systems had undergone noticeable changes. When the rat was returned to Earth and gave birth, the pups were weaker, smaller, and lagged behind their Earthly counterparts in mental development.
A large-scale experiment was conducted by American scientists Jeff Alberts and April Ronca, who sent 20 pregnant rats into space for the same purpose — to trace the effects of microgravity on pups. The rats were in the middle of pregnancy, when the vestibular apparatus began to form in the embryo. Mothers gave birth to rats of normal size and were able to feed and care for them. However, the scientists noticed that during the birth, the spacefaring rats needed twice as many contractile movements. They concluded that such a deviation was likely due to the weakening of the muscles in weightlessness.
The vestibular apparatus of the spacefaring rats was also affected – just as it had been in the fry of the Danio rerio aquarium fish. The control group pups were able to quickly roll over from their backs to their stomachs in water, while the spacefaring pups had difficulties with this: it took some of them several attempts, and others were not able to do it at all. But after five days of the same test, all of the pups were able to roll over, which once again proves the high adaptability of organisms to any conditions, as was the case with the fruit flies, salamanders and quails.
Experiments on drosophila, fish, amphibians and mice demonstrated that in vitro fertilization in space is possible, but it has a number of consequences due to microgravity and radiation: either germ cells are damaged, or the zygotes are reabsorbed after implantation. Therefore, the question then becomes: how can cells be protected from cosmic radiation and weightlessness?
That is why SpaceLife Origin is set on developing the Ark incubator. In the meantime, the company is creating a space transporter for the “seeds of life,” and NASA has already launched human sperm into space in order to study in more detail the effects of space phenomena on sperm motility. Results are pending.
While many questions remain regarding both the logistics and ethics of human reproduction in space, it is nonetheless clear that it is, indubitably, the direction of future research.