On July 20, 1969, astronaut Neil Armstrong became the first person to walk on the Moon. “That’s one small step for man, one giant leap for mankind,” he famously proclaimed, as more than half a billion people watched on television. For many, their minds were full of wonder and awe at man’s precarious place in a vast and inhospitable universe. But it can be assumed that at least a handful were thinking: “I wonder if you can get a boner in space?”

Well, it’s a valid query, and one that deserves a conclusive answer. First, though, we must understand how the body reacts to a low-gravity environment.

For starters, outer space hampers your heart. Per a recent NASA study: “Early studies on astronauts found that anemia (decrease of red blood cells in the bloodstream) of individuals returning from a space flight was due to selective hemolysis (destruction of red blood cells).”

Translation, given the topic at hand: Space reduces the number of red blood cells flowing through your system, which in turn, lessens the amount of oxygen-rich blood sent to your penis.

On top of that, low-gravity affects how blood is pumped through the body. Gravity on Earth typically pulls most of your blood to the lower half of your body, but in a low-gravity environment, blood flows instead toward the chest and head. According to NASA, this explains why many astronauts appear red and puffy-faced (the sudden comparative lack of blood flowing to and from the brain when they return to Earth can also cause dizziness).

Now, back to boners. When you combine fewer red blood cells with blood that’s redistributed toward your upper half, your ability to maintain a hard-on — which is essentially a sponge pumped full of blood — dwindles.

Now, it’s still possible to achieve an erection in outer space — it’s just that much more difficult.

Limited data also suggests that testosterone levels drop in space, which may contribute to erectile dysfunction. However, a 2011 study of both long- and short-duration space flights found little evidence to support this notion: “Total, free and bioavailable testosterone was not changed during long-duration space flight but were decreased on landing day after these flights and after short-duration space flight,” the study concludes.

Nonetheless, it’s possible that confined living quarters, lack of physical activity, lack of sexual activity, as well as changes in diet and sleep patterns may throw off arousal levels, which would certainly impact your ability to start your day with a salute to the sun.

Now, in rare cases, fluid shifts — i.e., when bodily fluids move into different compartments due to changes in pressure — may actually result in hard-ons harder than you’ve ever experienced on Earth. “A couple of times, I would wake up from sleep periods and I had a boner that I could have drilled through kryptonite,” astronaut Mike Mullane told Men’s Health.

Good to know!

All of this, however, may someday be a non-issue with the help of technology. “If you have a rotating space station — by way of the centripetal force of the rotating wheel — you can create any fraction of gravity you want, even 1G, which would be equivalent to Earth,” celebrity scientist Neil DeGrasse Tyson explained to National Geographic. “You could be in space, and on that perimeter of 1G, and [sex] is no different than what you’d be doing here on Earth, at all.”

Of course, this is way off from becoming a reality. Although once it does, you can be sure that people will want to test DeGrasse Tyson’s theory as soon as possible. And once we’re at that point, we’re sure to see the next inevitable step: Space porn.

It’s one small step for man, one giant boner for mankind.