The history of animals in space is a contentious one, with monkeys, frogs, and of course, Laika the Dog having paved the way for humans in space. More recently, in 2019, we sent mice to space to test microgravity.
Now, a new experiment by Japanese researchers involving mouse sperm may have set the way for sperm banks aboard spacecraft, allowing for colonization via in-vitro fertilization (IVF), a report by CNET explains.
The team, who published their findings in the journal Science Advances, set out to understand the long-term effects of space radiation on mammalian sperm.
For their experiments, they sent freeze-dried mouse sperm samples up to the International Space Station (ISS) back in 2013. Almost six years later, the samples were returned to Earth in a SpaceX Dragon cargo capsule in 2019, where they were successfully used to breed litters of healthy "space pups."
At the same time as the experiment was run aboard the ISS, mouse sperm samples were also frozen on Earth as a control group. The freeze-dried sperm from the ISS was used to impregnate female mice via IVF and these space pups were analyzed and compared to the "ground control" pups.
"Space pups did not show any differences compared to the ground control pups, and their next-generation also had no abnormalities," the team wrote in their paper.
The team also reported that no extra DNA damage occurred to the sample aboard the ISS when compared with the sample on Earth.
Moon-orbiting experiments likely to follow
One caveat to this research is the fact that the ISS is not stationed in deep space and it is partially shielded from the most dangerous radiation by the Earth's magnetic field.
Deep space exploration, which is where the applications for this research would most likely end up, may have a more detrimental effect on such samples.
The research may help to enable projects such as the University of Arizona researcher Jekan Thanga's proposed 'Lunar Ark', which aims to store DNA inside the Moon's lava tubes, as an archive for life on Earth and a "modern global insurance policy."
In fact, the team stated in its paper that it hopes to one day conduct freeze-dried sperm experiments on NASA's planned lunar Gateway project, which will launch a lunar outpost to orbit the Moon. This would allow them to gain a better understanding of the effects of radiation deeper into space.