The sniffling, sneezing astronauts of the Apollo 7 mission: Donn Eisele, Walter Schirra and Walter Cunningham.

Image courtesy NASA

The Apollo command module, which took U.S. astronauts to the moon in the 1960s and 1970s, was a high-tech bucket of bolts, wires and circuits. It's tough to imagine that three men in bulky spacesuits spent almost 11 days crammed into the capsule as it raced to space and back.

Now imagine that all three astronauts inside got sick simultaneously, coughing, hacking, and sneezing. That's what happened in 1968, when the crew of Apollo 7 tested the command module in Earth's orbit.

Astronauts Wally Schirra, Walt Cunningham and Donn Eisele all came down with head colds at the same time. It was so bad that the astronauts wouldn't don their helmets during re-entry, wary of their stopped-up ears popping painfully. For most of the flight, the trio had been sneezing, coughing and doing all the other things that people with colds do [source: Klunger].

Although George Clooney or Sandra Bullock didn't sneeze in the movie "Gravity," real astronauts do. They also cough and blow their noses. Frank Borman in Apollo 8, the first manned mission to the moon, vomited and had diarrhea [source: Howell]. All of these lovely events might happen in the cozy confines of a spaceship or out on a spacewalk with a helmet on. The things that make an astronaut sneeze in space are the same things that make all of us sneeze on Earth. Ready to find out what they are?