If you're planning to have sex during a weightless trip through space, be sure to bring some leather straps along with you.
At least, that's astrophysicist Neil deGrasse Tyson's advice for any would-be space travelers hoping to get busy on a trip through the cosmos.
Tyson, the host of the Star Talk talk show, answered one fan's question about sex in space with a little humor and a whole lot of science in a video posted this week.
"If you want to sort of get together [and] stay together, you need something to, like, keep you together during all the normal body movements that would characterize having sex in space," Tyson said in the video. "So yeah, just bring a lot of leather belts to keep things strapped down and you'll be just fine."
Of course, these kinds of anti-weightlessness measures are only necessary if you're in a zero-gravity ship, he added.
If the spaceship were rotating in some way, then it could produce some kind of artificial gravity that would mitigate the need for leather belts, but currently, those spinning starships are mostly in the realm of science fiction (though engineers have studied the mechanics that would actually go into building one).
As for real sex in space, NASA has denied any knowledge that astronauts or cosmonauts have done it off-Earth.