Sex in space is so much harder than you could have ever imagined

For as long as people have been going into space, other people have been wondering, “Are they, you know, doing it up there?”

A question nearly as old as time, or at least as old as the MIR space station, where in the 1990s, the first mixed crews spent any significant length of time together in space. Since then a bunch of other men and women astronauts have lived together for various stretches of time on the International Space Station, which has only enhanced the public’s curiosity about space sex.

But, as you’ll see, getting it on in space is still very much a case of ‘close but no cigar.’ And no space sex means no space babies, which will be a bummer for our plans to live on Mars–or anywhere else in outer space. Still it’s not all doom and gloom, and it’s certainly all interesting stuff, the stuff of life, so let’s get into the nitty-gritty of sex in space.


If you went out and had a lot of drinks with a bunch of astronauts, you might hear them say that there’s a lot of sex happening in space—just not with other people. The same natural urges felt on Earth are felt in space, so astronauts are intimately familiar with what it’s like to masturbate while weightless. If you are curious about details, please avail yourself of this introduction to the ‘space toilet’, and how astronauts dispose of what comes out of their bodies while they’re on mission. Let’s just say that everything tied up in a bag enjoys a fiery hot death on re-entry after being cruelly ejected from the waste disposal.

So there, that is out of the way. But sex between crew members—the only people who’ve ever been into space—has never happened, according to those who’ve been there.

“I was an astronaut for 21 years and I know of absolutely no instance on any spaceflight,” retired Commander Chris Hadfield told me over the phone of his three journeys into space.

One married couple went to space—Mark Lee and Jan Davis, who flew together in 1992 and divorced in 1998—before NASA forbade the practice because of the effect it could have on crew dynamics. Privacy on the ISS is impossible anywhere but the tiny room of the space toilet, but the nosey press asked at the time about the likelihood of the newlyweds consummating their love on the space station. “It’s none of your business,” said NASA in 1992. When I asked NASA what the official line on space love among crew members is today, the public relations office replied, “While we expect our employees to behave in a professional manner at all times, their personal lives are their own until it begins to directly affect their job performance.”

This seems to be pretty solid advice about not sleeping with your colleagues, something which rarely ends well on Earth, let alone in space, where everyone is counting on everyone else to protect each other’s lives.

“It’s a normal, regular human behavior,” said Hadfield of intimacy in space. “But at the moment we’re pretty constrained.”

There are two big constraints. The first is how busy people are when they’re in space. Even if they wanted to and it were physically achievable, astronauts on space missions just don’t have time to have sex; they’re there to do a job, one that could kill them if something goes wrong. The second is that, because of the laws of physics, sex in space is really, really hard to make happen. Just as using a toilet in space presents a unique set of challenges, so does every single other physical undertaking, including sex, which is complicated by the fact it involves two people trying to connect with each other among the forces of Newtonian physics:


Congratulations! You have made it to space and are now eager to engage in some red hot sexy space times. Be warned, in zero gravity, physics behave very differently than on Earth.


Oh dear, in coming into contact with each other in zero gravity you have collided with some force.


The mass of the heavier one of you coming into contact with the lighter one has sent your paramour flying across the room. Newtonian physics conspires against your attempt to making sweet, sweet space love.


Possible solution! With nowhere to fly off to and plenty of in-built restraining, this could be the not especially comfortable solution—being literally trapped together in a very confined area. But you love each other, so there is nothing you wouldn’t do for space nookie.


There has been one attempt made to try and come up with a solution to the sex in weightlessness problem: A practical but not super-sexy contraption called the 2Suit, which was designed by Vanna Bonta, a writer, and tested inside a zero G simulator for a 2009 History Channel documentary. The suit was designed to velcro two people together inside it, hoping to prevent them from sending each other flying away at every touch in weightlessness, by trapping them together in a kind of space onesie for two:

Prototype at left, in action at right.

Prototype at left, in action at right.

No actual sex was had in the suit, but eventually a kiss was achieved:

“In two years’ time people could go on their honeymoon in space,” Bonta told Wired in 2009. That was a tad optimistic; in 2016, we’re not remotely near honeymooning in space, but people do get married in zero gravity planes.

2001-a-space-odyssey-baby-2001-starchild-and-earth2001: A Space Odessy

Meanwhile, it seems that NASA is not coming up with any serious solutions for sex in space, and it is not alone. The European Space Agency and the private space outfit SpaceX, whose founder Elon Musk wants us to live on Mars, also indicated they had no interest in the topic. But there is more to this than salacious interest: How are we going to reproduce in space? The signs so far are not at all encouraging, which may be very bad news for those futurists dreaming of a permanent Mars colony.

Only 24 people have traveled to deep space, all of them men, including the all-male Apollo crews who walked on the Moon. Of the 536 people total who have been into space, only 60 have been women, resulting in very little medical literature on the effects of the space environment on women’s bodies.

We do know though that the most at-risk astronauts are younger, pre-menopausal women—the same women who would need to bear any future space children. Space radiation increases their likelihood of developing cancer. The wastage of bone and muscle density that happens in weightlessness could pose a catastrophic risk to the healthy development of a fetus, and loss of bone density in their hips specifically would drastically affect any natural birth in space in the same way osteoporosis can in some women on Earth.

Beyond the health of the mother, we know little about the effect space would have on the gestation, delivery, growth and development of a human fetus in utero. There have been no human reproductive trials in space and there are no plans for any in the foreseeable future. Animal trials are the only steps that have been taken so far to judge how human reproduction in space might fare. Research has to start somewhere, even somewhere very, very far from humans, with the test subjects limited to insects, plants, frogs, sea urchins, fish, rats and mice.

Invertebrates like jellyfish have produced offspring in zero gravity, but those offspring had developmental and Earth readjustment problems as a result of being born in weightlessness. In the case of the jellyfish born in space, on returning to Earth they could not orientate themselves when they tried to swim, unable to tell up from down because the tiny crystals in their bodies which form on Earth and communicate orienting signals to their brains did not develop properly in space. These communication pathways closely mimic the ones humans have in their inner ears which allow us to achieve our sense of balance. The good news: Jellyfish eventually regained their sense of direction when swimming on Earth after a significant period of readjustment.

In the case of mice, mammals like us, a 2014 NASA report notes that the one experiment conducted in the 1980s to get mice to mate in space resulted in no viable offspring. A more recent experiment, in 2009, took the easier route and tried to fertilize mice eggs in vitro in space. It was equally disappointing: The eggs were successfully fertilized, but the resulting birth numbers were low and the mice born had developmental delays and cell damage. In a current study underway, adorably named “Space Pup,” Japanese researchers are storing “freeze-dried mouse sperm” on the International Space Station for years at a time and then using it to fertilize mouse eggs on Earth to study the effects of space radiation.

“Space Pup represents the first step towards studying the effects of space radiation on mammalian reproduction, which must be understood to sustain life beyond Earth,” wrote the researchers in their abstract.

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Collier's Magazine, 1952

It’s a serious issue. The effect of radiation on sperm and ovum health could result in sterility in human beings while in space, even on short trips. Pregnant women on Earth can’t be x-rayed without robust shielding to protect their fetus, and women on the space station are exposed to many times the amount of radiation produced by a single x-ray.

As astronaut Chris Hadfield says, the questions of human space reproduction are fundamental, vexing and steadfastly unknown: “Can you gestate properly up there? What happens in gestation but even more importantly what happens in development? Will a human body develop without the load of gravity? What would your skeleton look like? If you took an infant and immersed them in jello for the first ten years of their life, would they be able to ever stand?”

Given the ethical concerns around testing out the effects of space on human embryos, don’t expect human trials any time soon. Pregnant women are banned from flying by all space programs because of the unacceptable risk it would pose to an unborn child, thanks to the combination of G-forces, radiation and zero gravity.

When it comes to space, we don’t even know what the longterm effects are for full-grown humans who spend months-long periods of time on the space station. Astronauts are our test subjects to figure it out, and often remain so even after they retire. Some have allowed their bodies to be drilled into to give up muscle samples. Others have inserted a rectal probe or catheter during the launch to monitor their body functions.

“That probably helps put the frivolity of libido and sex into maybe its true perspective,” Hatfield says. “That’s what we’re actually doing to understand how the human body works in space and how it adapts.”

In other words, we don’t know a whole lot about the long-term effects for people who have been to space, let alone how theoretical space babies would fare. For now, protecting astronauts from cosmic rays while still allowing them to explore the insanely dangerous and hostile environment of space is the priority of agency programs, which might change in the future as the body of knowledge grows and reproductive experiments on mammals and plants incrementally progress.

But the thought of jetting off to Mars in the next decade with the intention of establishing a permanent settlement where people will raise their kids is the stuff of total fantasy that no current medical data on astronauts supports. No agency has active plans for a colonization mission. NASA’s plan for Mars, if it can get government funding, is to send a crewed mission to the planet sometime in the 2030s, a crew that will return.

The hard truth about people and space is that humans were just never designed to live there. We were designed to live on this planet, and at least for the next long while, that’s where the human babies of the future will be born.