What happens when astronauts fart in space? Discover Disco Blog dug up a University of California, Berkeley study from 1969 on "intestinal hydrogen and methane of men fed (a) space diet."
Or, the potential buildup of hydrogen and methane in people on a space diet.
Or, what happens when you pass gas in space?
Like passing gas while on a date, letting one rip in space in a closed and confined space is not an ideal situation. Dietary test groups were set up based on Gemini mission diets and alternate diets:
Breath and rectal gases were analyzed during the first and final weeks. Flatus gases varied widely within dietary groups but much more gas was generated with diet S than with F. In the first 12-hour collection, subjects fed S passed 3 to 209 ml (ATAP) of rectal H2 (avg 52) and 24 to 156 ml (avg 69) from the lungs (assuming normal pulmonary ventilation). With F, these values were 0 to 3 ml (avg 1) and 6 to 36 ml (avg 20). Subjects were calmer during the second test. Gas production was lower with S than initially; F values were unchanged. Methane differed idiosyncratically, presumably due to differences in flora. Computed from 12-hour values, maximum potential daily H2 and CH4 are per man: for S, 730 ml and 382 ml; for F, 80 and 222 ml. Volumes would be larger at reduced spacecraft and suit pressures.
It wasn't the first time NASA had studied flatulence in space. A 1965 astro-fart study by the agency bore the title "Review of physiology and pathology of gastrointestinal tract as related to space flight conditions."
As i09 points out, the astronauts on the Gemini missions must have had an awful time holding in gases because of their high gas producing diet.
And during the Apollo program, there was some concern among NASA engineers that flatulence in space could trigger an explosion, according to the Orange County Register.
That never happened.