Actually, according to this Atlantic blog post, in space, you can’t really cry at all.
Astronauts can, certainly, tear up—they’re human, after all. But in zero gravity, the tears themselves can’t flow downward in the way they do on Earth. The moisture generated has nowhere to go. Tears, Feustel put it, “don’t fall off of your eye … they kind of stay there.”
Read the whole thing for weird revelations about how the human body fares away from Earth, as well as plenty of crying-astronaut puns.