Sex in space has been posing a problem for decades, but an experiment on the International Space Station could soon pave the way for astronauts to join the 100-Mile High Club.
The issue is not, as you might expect, a mechanical one – although since no one has tried to make space love, we do not quite know how it might work out.
The primary concern with amorous orbiting couples is the conception of a child, and what effects microgravity and radiation might have on either the mother or baby.
However, a breakthrough experiment on the International Space Station has shown normal development of mouse embryos while in orbit, suggesting human embryos may also be able to develop under the same conditions.
And while the subject of sex in space is always an entertaining one, it is also serious business if humans want to become an interplanetary species.
‘There is a possibility of pregnancy during a future trip to Mars because it will take more than six months to travel there,’ said Dr Teruhiko Wakayama at the University of Yamanashi in Japan, who led the study. ‘We are conducting research to ensure we will be able to safely have children if that time comes.’
Speaking to Metro.co.uk’s sister publication New Scientist, Dr Wakayama said he and his colleagues first grew the embryos on Earth, extracting them at the two-cell stage and freezing them for their journey into space aboard a SpaceX rocket.
Once on board the ISS, astronauts thawed the embryos and cultured them for four days – the longest they can survive outside a uterus. They were then chemically preserved and sent back to Earth for analysis.
After their journey the embryos showed no signs of DNA damage from radiation, and no signs of abnormal structure development from the microgravity environment.
Space sex – how is it done?
The honest answer is… no one knows.
As far as Nasa, the ESA, Roscomos and other space agencies are concerned, the official line is that no one has ever ‘done it’ in space.
Unfortunately for one journalist, a hoax about space sex did once hit the headlines.
In 2000, respected science writer Pierre Kohler fell for a story claiming both Nasa and Roscosmos had conducted separate experiments during which two astronauts had actually engaged in a bit of space sex, finding only four positions achievable ‘without mechanical assistance’.
The project was allegedly codenamed STS-XX. Computer simulations were used to test 20 sexual positions, selecting the best 10 for a real life experiment.
‘Two guinea pigs then tested them in real zero-gravity conditions,’ said Mr Kohler. ‘The results were videotaped but are considered so sensitive that even Nasa was only given a censored version.’
While four positions were deemed workable, the remaining six – including a classic – required a special elastic belt and inflatable tunnel to work.
‘One of the principal findings was that the classic so-called missionary position, which is so easy on Earth when gravity pushes one downwards, is simply not possible,’ said Mr Kohler.
Unfortunately, it was later discovered none of the experiments ever actually took place.
The embryos were thawed at a crucial stage, where the cells differentiate into two distinct groups that form the basis of the foetus and the placenta, but appeared to divide normally.
Further research is required before a human can be conceived in space, especially given the embryos were only exposed to four days’ space radiation, but the results, published in the journal iScience, are promising.
They also build on a previous Nasa experiment in which pregnant rats were sent to the ISS for nine to 11 days during the second half of their pregnancy. After a return to Earth, the rats gave birth to normal, healthy pups.
‘Based on [this] and our results, perhaps mammalian space reproduction is possible,’ said Dr Wakayama.
More research is also required to determine the effects of a microgravity pregnancy on the mother. For instance, an ectopic pregnancy, where the embryo does not descend into the uterus and attaches – usually – in the fallopian tube, could be more likely.
The effects of microgravity on birth are also unknown – for instance, whether it would make delivery harder.
But before that stage, Dr Wakayama and his team will implant embryos that have travelled to the ISS into mice to see if they develop into healthy offspring.
However, some argue that the research into human reproduction in space will need to pick up the pace following the rapid rise of space tourism.
Earlier this year, the authors of a report titled ‘Sex in Space: Consideration of uncontrolled human conception in emerging space tourism’ said it was ‘unrealistic to assume that all space tourism participants will abstain from sexual activities’.
They added: ‘This raises the possibility of uncontrolled human conception in space.
‘Potential detrimental outcomes and risks include those of a biological nature such as maternal complications related to conception and embryo, foetal, neonatal and later abnormalities.’
So far there has been relatively little research in the field from a human angle by national space agencies because the focus is quite firmly elsewhere, and professional astronauts are thought unlikely to risk their jobs or reputations by engaging in any unsanctioned orbital sex.
Last year Nasa hinted it was considering studying sex in space, and has conducted a study into the effects of microgravity and space radiation on human sperm motility, but the results are not yet available.
However, if humans truly hope to one day become an interplanetary species, these are all questions that will need to be answered.
Making babies in space will be vital to keeping civilisation alive.
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