Can Humans Have Sex in Space?

sex in space
Making love in space is likely to be a bit tougher due to weighlessness and other factors. Tim Robberts/Getty Images

One of the more popular questions fielded by astronauts focuses on the more personal aspects of space exploration: has anybody "hooked up" in low-gravity conditions. It's actually right up there with "How do astronauts use the bathroom in space?"  Lots of speculation exists about whether or not two people have had sex in space, but so far as anyone knows, no one has gotten away with it yet. (Or, if they have, nobody's talking.) It's certainly not part of their astronaut training (or if it is, it's a well-kept secret). However, as humans venture out on long-term missions in low-Earth orbit and possibly even to other planets, sex in space is going to happen. Humans are human after all, even out in space.

Is Sex in Space Possible?

From a physics standpoint, sex in space looks as though it might be difficult to achieve. The microgravity environment that astronauts experience on the International Space Station, for example, causes all kinds of problems for living and working in space. Eating, sleeping, and exercising are all more complicated acts in space than they are on Earth, and sex would be no different.

For example, look at the regulation of blood flow, important for both sexes, but particularly for men. Low gravity means that blood doesn't flow throughout the body the same way it does as on Earth. It will be much more difficult (and perhaps even impossible) for a male to achieve an erection. Without that, sexual intercourse is going to be difficult—but of course, many other forms of sexual activity are still possible.

The second problem is sweat. When astronauts exercise in space, their sweat tends to build up in layers around their bodies, making them sticky and wet all over. This would give the word "steamy" a whole new meaning and may make intimate moments slippery and uncomfortable.

Since blood doesn't flow the same way in microgravity as it does on Earth, it is not a reach to assume that the flow of other vital fluids would be inhibited as well. However, this may only be important if the goal is to make a baby.

The third and most interesting problem relates to the motions involved in sexual activity. In a microgravity environment, even a small push or pull motion sends an object hurtling across the craft. This makes any physical interaction quite difficult, not just intimate ones. 

But there is a fix for these difficulties—the same fix used to overcome the difficulty of exercise in space. When they exercise, astronauts strap themselves into harnesses and fasten themselves to the spacecraft walls. This would presumably allow couples to engage in sexual activity as long everything else is working smoothly (see discussion of blood flow regulation above.) 

Has Sex in Space Happened?

For many years rumors claimed NASA sanctioned sexual experiments in space. These stories have been categorically denied by the space agency and the astronauts. If other space agencies have done this, it's been a closely held secret, too.  One thing's for sure: even if two (or more) people managed some space nookie, someone would know. Unless they unhooked all their heart monitors and found a truly private place, people at mission control would see an uptick in heart rates and respiration. Plus, space travel takes place in close quarters and is anything but private.

Then, there's the question of astronauts taking matters into their own hands and having a full-on space orgy. Most have commented that this is extremely unlikely. As mentioned above, space quarters are pretty tight and there really aren't a lot of places for two or more people to engage in a little off-hours close-order drill. Also, astronauts on very tight schedules and have few free moments to squeeze in unauthorized activities.

Will Sex in Space Ever Happen?

Space sex is probably an inevitable outcome of longer-term exploratory missions. Certainly, no one expects crew members on a long-term voyage to abstain from all sexual activity, so it would be wise for mission planners to come up with sensible guidelines. 

A related issue is the possibility of pregnancy in space, which is much more complicated. As humans pursue longer trips to the Moon and planets, perhaps future generations will also wrestle with issues related to pregnancy and childbirth.