An astronaut has many things to worry about - the safety of the mission, the claustrophobic surroundings and the loneliness of the venture. But now, they have one more thing to worry about - flatulence. As humans produce two flammable gases - hydrogen and methane - which ignite when accumulated in an enclosed space, astronauts are potentially at risk as they are cooped up in their spacecraft. The study, was the work of Edwin L. Murphy and Doris H. Calloway, a nutrionist, reported io9 website. The research analysed breath and rectal gases of people on a \'space diet\' compared to a diet used on earlier Gemini missions in the 1960s. They studied what the effects could be of a potential build up in expelled hydrogen and methane gases. The paper, published in 1969, found that: \'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 of rectal H2 and 24 to 156 ml from the lungs. \'With F, these values were 0 to 3 ml  and 6 to 36 ml. \'Subjects were calmer during the second test. Gas production was lower with S than initially; F values were unchanged. \'Volumes would be larger at reduced spacecraft and suit pressures.\' They found that a new, bland diet produced a lot less gas than the one that was fed to the Gemini astronauts, io9 reported. Their paper formed part of a loose trilogy of flatulence-related papers which  began with 1968\'s \'The Use of Expired Air to Measure Intestinal Gas Formation\' and concluded with 1971\'s \'Reduction of Intestinal Gas-Forming Properties of Legumes by Traditional and Experimental Food Processing Methods.\' Flatulence is a mixture of gases such as nitrogen, carbon dioxide, methane, hydrogen, oxygen, and hydrogen sulphide. These gases are produced by bacteria in the large intestine which break down food into amino acids, glucose and fatty acids. Gas is a by-product of their work. Irrespective of the diet, loosing some 12 to 40 \'winds\' (that is, 0.5 to 2.0 litres of gas) per day is normal. The cellulose in vegetables cannot be digested, therefore vegetarians produce more gas than people with a mixed diet. Men and women emit the same amounts of gas as there is no difference in the chemistry of male and female digestion.