The Real Reason Astronauts Don't Burp In Space

Being an astronaut isn't all that it's cracked up to be. Not only is it extremely difficult to make the cut for any given space mission; there are a lot of things that are part of our daily lives on Earth that astronauts have to do differently in space. Eating, for one, isn't exactly as fun as it looked when Homer Simpson opened a bag of chips and gobbled up its contents while floating in the Space Shuttle, with Johann Strauss II's "The Blue Danube" providing the soundtrack for the classic cartoon scene. 

Consuming freeze-dried space food and moisturizing it with a water gun sounds inconvenient enough. But what about that ubiquitous thing that happens after one has eaten a rather hearty meal? Burping, of course, is to be expected when you're full, and we here on Earth are likewise expected to follow proper etiquette and cover our mouths when we do so. Unfortunately, that's not an option for astronauts, who can't even burp normally while in space without suffering uncomfortable consequences. But why is this the case?

In November 2018, a Twitter user had an interesting question for former International Space Station (ISS) Commander Chris Hadfield, posting a photo of a Snapple cap and the "real fact" underneath it, which read "astronauts can't burp in space." When asked by the user if this is true, Hadfield answered in the affirmative, explaining that this is because "the air, food and liquids in your stomach are all floating together like chunky bubbles. If you burp, you throw up into your mouth. So guess where the trapped air goes?"

As further explained by Business Insider, gas normally rises to the top of a person's body through their mouth because it's lighter than the solids (food) and liquids (stomach juices) in the gut. But in zero-gravity settings, such as in outer space, the gas remains in the stomach and doesn't separate from its liquid content like it normally would on Earth. So if an astronaut belches in space, that results in a "wet burp" with some liquid expelled. Or if you ask the United Kingdom's National Space Centre, such an experience is known as a "bomit" — a portmanteau of "burp" and "vomit" that basically says it all.

According to Popular Science, that's the very reason why NASA prohibits its astronauts from bringing soda, beer, and other carbonated drinks with them to space. Considering how common it is for intoxicated people to belch or throw up when they've had at least one beer too many, it's certainly for the better.

Certain astronauts have tried working around the wet burp problem in a number of ways. In a 2004 interview published on NASA's website, TST-2 astronaut Joe Engle recalled that during their mission, technical issues resulted in their water supply becoming "very bubbly" due to the hydrogen that had seeped in. Consuming that water would have been akin to "[drinking] a Coke real fast [while] it's still bubbly," so to avoid those wet burps, Engle and his fellow crew members chose to stop drinking the water. Naturally, that made the astronauts "tired and dehydrated" once they returned to Earth.

Another astronaut was able to come up with a technique that allowed him to burp normally — at least by outer-space standards. Ariel Waldman's 2016 book What's it Like in Space? featured an account from NASA's Jim Newman (pictured above), who created an artificial — and momentary — form of gravity by pushing himself off a wall. This method, known as the "push and burp," essentially allowed him to "[keep] his food down in his stomach, giving him a brief chance at expelling gas without consequence," as quoted by Business Insider.