When prompted with the topic of sex in space, Neil deGrasse Tyson gives some sound advice. “Bring a lot of leather belts,” he says with a laugh. Whether it’s James Bond and Dr. Holly Goodhead going for a celebratory Moonraker romp, or space vampire Mathilda May giving it the ol’ college try in Lifeforce, nerd-kind has long been fascinated with the concept of cosmological coitus. But on a recent episode of StarTalk, NdGT explained that – like most things we see on the silver screen – space sex would be a bit more complicated in real life.

Now we’re assuming for the purposes of this explainer that you are not having sex on a hypothetical, rotating space station. If you were spinning at the right velocity (think that running scene in 2001: A Space Odyssey), the artificial gravity caused by centripetal force would make your interstellar sexy-time relatively indistinguishable from that here on Earth. You’d have to be on an incredibly large spacecraft to make it work, so let’s stick with what we know: in micro-gravity (what astronauts experience on the International Space Station), things get a bit tricky.

Gravity causes every object to pull every other object toward it. Remove the bulk of that force, and well, body-docking becomes quite difficult. “You start to see the manifestations of Newton’s laws of motion,” says Tyson. Newton’s second law, which deals with accelerating masses, tells us that without the forces of gravity or friction, you could (quite literally) thrust your partner into the great wide forever (or into a wall, whichever happened first) with very little effort. There’s also that pesky third law of motion to contend with: every action has an equal and opposite reaction. “You push against something, and it just bounces off,” notes Tyson.

But let’s say you got around the physical logistics, as Tyson recommends, by strapping yourselves together. Then what? There are a number of other factors to consider. The biggest one is sweat. In a minimal gravity environment, liquid doesn’t fall like it does in sector 2814. Remember when Canadian Space Agency astronaut and prolific Twitterer Chris Hadfield showed us what happens when you cry in space?

Yeah, you get the idea.

Of course, Tyson’s video has prompted a slew of follow-up questions like, “could you ejaculate in space?” While some argue that the decreased blood pressure experienced in low-gravity would make it difficult for men to perform, cosmonaut Alexandr Laveikin seems to disagree. “My friends ask me, ‘How are you making sex in space?’ I say, ‘By hand!'” he told science writer Mary Roach during research for her book, Packing For Mars. One thing’s for sure, “spaceturbation” could be a very messy venture without the proper cleanup protocols.

And speaking of research, should you decided to take a dive into the plausibility of weightless sex for yourself, a quick Google search will likely result in the discovery that NASA has allegedly conducted a study on the matter. “It’s the biggest hoax on the internet,” clarifies Roach. The paper in question, known across the webscape as “12-571-3570,” claims to detail the results of some dozen experiments conducted aboard STS-75, wherein couples “came to fruition” in various positions to determine which was the best for in-orbit procreation. Considering the STS-75 didn’t launch until seven years after the supposed study was released, it’s safe to say this myth is busted (no pun intended).

Whether or not NASA has an official policy on mid-mission sex is unclear, but it’s worth noting that these men and women live in extremely close quarters (the sleeping chambers aboard the ISS have been compared to traditional telephone booths). I don’t even know where a pair of concupiscent explorers could do the deed, even if they wanted to.

NASA astronauts Ron Garan and Cady Coleman, European Space Agency astronaut Paolo Nespoli, and Russian cosmonaut Alexander Samokutyaev pose for a photo in the Harmony Node of the ISS. Source: NASA

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IMAGES: Canadian Space Agency/YouTube, NASA, NASAeClips/YouTube