# Could an astronaut fart himself back to the space capsule? **URL:** \ **Category:** Factual Questions\ **Created:** [January 27, 2009, 1:58pm UTC](https://boards.straightdope.com/t/could-an-astronaut-fart-himself-back-to-the-space-capsule/483223 "2009-01-27T13:58:03Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![mnemosyne](https://avatars.discourse-cdn.com/v4/letter/m/c4cdca/32.png) [@mnemosyne](https://boards.straightdope.com/u/mnemosyne)\ **Post date:** [January 28, 2009, 12:25am UTC](https://boards.straightdope.com/t/could-an-astronaut-fart-himself-back-to-the-space-capsule/483223/21 "2009-01-28T00:25:49Z")
Back in Cégep, in a physics class, we had a problem from the textbook assigned as homework. The question was whether turning a flashlight on and off would allow a stranded astronaut to get back to his space ship. Once all the numbers were crunched, it turned out that the answer was “no”. So the poor astronaut probably died out there. This is the same textbook that had Tarzan rescuing Jane by swinging them on a vine over a pit of hungry crocodiles, and once we did the math, we discover that the _vine breaks_ and they cannot make it across the ravine. There was also the beer mug being slid along a bar top and the drunk’s reaction time wasn’t fast enough to grab the mug, so it falls to the floor and breaks. This book was full of very sad problem sets! ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [January 28, 2009, 1:29am UTC](https://boards.straightdope.com/t/could-an-astronaut-fart-himself-back-to-the-space-capsule/483223/22 "2009-01-28T01:29:15Z")
> [@](#): > > This book was full of very sad problem sets! That’s nothing. One of the physics professors here has a friendly rivalry with one of the engineering profs… Not a page goes by in the physics prof’s problem book that the engineer doesn’t fall to his death or get eaten by a grizzly or crash an experimental rocket sled or suffer some other such gory fate, and I understand that the engineer uses the physicist in a similar way in his classes. ---
**Author:** ![WarmNPrickly](https://avatars.discourse-cdn.com/v4/letter/w/d78d45/32.png) [@WarmNPrickly](https://boards.straightdope.com/u/WarmNPrickly)\ **Post date:** [January 28, 2009, 1:36am UTC](https://boards.straightdope.com/t/could-an-astronaut-fart-himself-back-to-the-space-capsule/483223/23 "2009-01-28T01:36:44Z")
> [@BrandonR](#): > > You’ve never eaten at a Mexican buffet, have you? That alone could give me the energy for a one-man trip to Mars. But now your talking about a liquid gas mixture which would have more density. Plus, if the water hasn’t been boiled, then you have a whole day of “momentum” coming out of several orifices. ---
**Author:** ![HMS\_Irruncible](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hms_irruncible/32/7394_2.png) [@HMS\_Irruncible](https://boards.straightdope.com/u/HMS_Irruncible)\ **Post date:** [January 28, 2009, 1:53am UTC](https://boards.straightdope.com/t/could-an-astronaut-fart-himself-back-to-the-space-capsule/483223/24 "2009-01-28T01:53:38Z")
If I found myself untethered from my spacecraft in deep space, I’d immediately lose whatever suitable reaction mass I had. Maybe astronauts are better trained in that regard. “In the event of an emergency, seal all openings first.” ---
**Author:** ![mnemosyne](https://avatars.discourse-cdn.com/v4/letter/m/c4cdca/32.png) [@mnemosyne](https://boards.straightdope.com/u/mnemosyne)\ **Post date:** [January 28, 2009, 3:22am UTC](https://boards.straightdope.com/t/could-an-astronaut-fart-himself-back-to-the-space-capsule/483223/25 "2009-01-28T03:22:39Z")
> [@Chronos](#): > > That’s nothing. One of the physics professors here has a friendly rivalry with one of the engineering profs… Not a page goes by in the physics prof’s problem book that the engineer doesn’t fall to his death or get eaten by a grizzly or crash an experimental rocket sled or suffer some other such gory fate, and I understand that the engineer uses the physicist in a similar way in his classes. Yes, but the book I was talking about was _published!_ Still, those problem sets sound pretty funny! I also once had a calculus prof discus probability with a Russian Roulette game; one bullet, six chambers. As he’s setting up the problem, his wife, Mary, another prof, knocks at the door and takes him aside to ask/tell him something, and he comes back in looking a little exasperated. He continues the problem set-up, and asks “what is the probability that Mary “wins” the game by finding the bullet?” AFAIK, they are still together 10+ years later, amazingly. ---
**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\ **Post date:** [January 28, 2009, 8:07am UTC](https://boards.straightdope.com/t/could-an-astronaut-fart-himself-back-to-the-space-capsule/483223/26 "2009-01-28T08:07:19Z")
> [@ElvisL1ves](#): > > Liquid propulsion systems would have a higher specific impulse. Just open that little flap in front of the pressurized union suit. Quite correct. Nobel prize winner Richard Feynman did some experiments on this while at college. He showed (long before space travel) that urination is under muscular control, and is NOT dependent on gravity. ---
**Author:** ![elconqueeestador](https://avatars.discourse-cdn.com/v4/letter/e/8baadc/32.png) [@elconqueeestador](https://boards.straightdope.com/u/elconqueeestador)\ **Post date:** [January 28, 2009, 5:35pm UTC](https://boards.straightdope.com/t/could-an-astronaut-fart-himself-back-to-the-space-capsule/483223/27 "2009-01-28T17:35:58Z")
O.K. let’s take this a step further. Since it is universally known that farts are flammable here on earth how would adding a strategically placed igniter (i.e. like those in bbq grills) to the flatulence vent influence the suit’s anal propulsive properties? :eek: ---
**Author:** ![Jake](https://avatars.discourse-cdn.com/v4/letter/j/f475e1/32.png) [@Jake](https://boards.straightdope.com/u/Jake)\ **Post date:** [January 28, 2009, 6:07pm UTC](https://boards.straightdope.com/t/could-an-astronaut-fart-himself-back-to-the-space-capsule/483223/28 "2009-01-28T18:07:16Z")
Bump. This thread is too good to fade away! 😃 ---
**Author:** ![WarmNPrickly](https://avatars.discourse-cdn.com/v4/letter/w/d78d45/32.png) [@WarmNPrickly](https://boards.straightdope.com/u/WarmNPrickly)\ **Post date:** [January 28, 2009, 6:27pm UTC](https://boards.straightdope.com/t/could-an-astronaut-fart-himself-back-to-the-space-capsule/483223/29 "2009-01-28T18:27:50Z")
> [@elconqueeestador](#): > > O.K. let’s take this a step further. Since it is universally known that farts are flammable here on earth how would adding a strategically placed igniter (i.e. like those in bbq grills) to the flatulence vent influence the suit’s anal propulsive properties? :eek: Without an oxygen source, it won’t do anything. On the other hand, I don’t see anything that could go wrong with hooking an oxygen source to your rectum and igniting it. Nothing at all could go wrong. ---
**Author:** ![ElvisL1ves](https://avatars.discourse-cdn.com/v4/letter/e/5daacb/32.png) [@ElvisL1ves](https://boards.straightdope.com/u/ElvisL1ves)\ **Post date:** [January 28, 2009, 6:34pm UTC](https://boards.straightdope.com/t/could-an-astronaut-fart-himself-back-to-the-space-capsule/483223/30 "2009-01-28T18:34:46Z")
What if the hamster in there adds his own thrust? ---
**Author:** ![EdwardMartinIII](https://avatars.discourse-cdn.com/v4/letter/e/59ef9b/32.png) [@EdwardMartinIII](https://boards.straightdope.com/u/EdwardMartinIII)\ **Post date:** [January 28, 2009, 7:58pm UTC](https://boards.straightdope.com/t/could-an-astronaut-fart-himself-back-to-the-space-capsule/483223/31 "2009-01-28T19:58:25Z")
> [@Ponderoid](#): > > If the suit is designed to vent, the astronaut wouldn’t have to fart. The suit’s air would serve as reaction mass. Actually, this seems like it could possibly work. If an astronaut, say, had only j-u-s-t missed a grip, and needed a nudge to reach the cable (for example, in **Mission to Mars** , where everybody was going to be in a ship in a few minutes anyway and Tim Robbins was only inches away from the rope), I can imagine the last desperate attempt being to basically stab a hole in the suit to vent, and pursing (as well as modern suits can allow) the hole enough to increase the gas escaping velocity. Definitely better get into atmosphere quick, and definitely _definitely_ don’t want a Bad Guy to puncture your suit in the opposite direction, leaving you to pinwheel. It is almost certainly the case, that if you _were_ holding in a fart, that would be released as well. And that could be detected by distant alien astronomers and almost certainly interpreted as life. Which only confirms my suspicion that we need to complement our extrasolar planet survey with Smell-O-Scope results. Just to be sure. ---
**Author:** ![palindromemordnilap](https://avatars.discourse-cdn.com/v4/letter/p/db5fbb/32.png) [@palindromemordnilap](https://boards.straightdope.com/u/palindromemordnilap)\ **Post date:** [January 30, 2009, 2:33pm UTC](https://boards.straightdope.com/t/could-an-astronaut-fart-himself-back-to-the-space-capsule/483223/32 "2009-01-30T14:33:05Z")
spaceship grafitto: Here I float One last chance Need to toot But crap my pants ---
**Author:** ![Freddy\_the\_Pig](https://avatars.discourse-cdn.com/v4/letter/f/a587f6/32.png) [@Freddy\_the\_Pig](https://boards.straightdope.com/u/Freddy_the_Pig)\ **Post date:** [January 30, 2009, 4:19pm UTC](https://boards.straightdope.com/t/could-an-astronaut-fart-himself-back-to-the-space-capsule/483223/33 "2009-01-30T16:19:05Z")
> [@Dervorin](#): > > For an average 60kg astronaut, his (or her, of course) velocity would be a rather pitiful 2.32 \* 10^-6 m/s. 2.32 micrometers per second isn’t going to get you anywhere much. And yet, all is not lost, because as **Santo Rugger** so astutely points out, the effect of additional farts is cumulative! Suppose the astronaut had enjoyed the freeze-dried Mexican Fiesta Pak just before the spacewalk, and was tooting at the rate of one fart per minute. That’s a lot, but I’ve had gas attacks that were worse. After one hour, given your assumptions, the astronaut would have traveled 250,000 micrometres, or a quarter of a meter! A second hour, even without any further tooting, would cover another half-meter via momentum alone. Granted, that’s a lot of flatulence to travel a short distance, but it might be the difference between life and death! ---
**Author:** ![Icerigger](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/icerigger/32/432_2.png) [@Icerigger](https://boards.straightdope.com/u/Icerigger)\ **Post date:** [January 30, 2009, 4:37pm UTC](https://boards.straightdope.com/t/could-an-astronaut-fart-himself-back-to-the-space-capsule/483223/34 "2009-01-30T16:37:30Z")
What is more important, the mass of the reaction mass or it’s exhaust velocity? Say an astronaut was trapped in the center of a huge open space in a vacuum and he took off his clothes which have a mass of 3 Lbs. He starts to swing the clothes in a circle as fast as he can and lets go. I assume he will move in the opposite direction of the clothes at some velocity, yes? If he just gently pushed the clothes away his delta-V would be much, much less, correct? ---
**Author:** ![BestWifeEver](https://avatars.discourse-cdn.com/v4/letter/b/838e76/32.png) [@BestWifeEver](https://boards.straightdope.com/u/BestWifeEver)\ **Post date:** [January 30, 2009, 10:01pm UTC](https://boards.straightdope.com/t/could-an-astronaut-fart-himself-back-to-the-space-capsule/483223/35 "2009-01-30T22:01:43Z")
> [@Jolly\_Roger](#): > > In space no one can smell you fart. or hear you… …kinda takes the fun out of it. ---
**Author:** ![Infovore](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/infovore/32/420_2.png) [@Infovore](https://boards.straightdope.com/u/Infovore)\ **Post date:** [January 30, 2009, 10:20pm UTC](https://boards.straightdope.com/t/could-an-astronaut-fart-himself-back-to-the-space-capsule/483223/36 "2009-01-30T22:20:11Z")
(sorry, wrong place. D’oh!) ---
**Author:** ![flex727](https://avatars.discourse-cdn.com/v4/letter/f/258eb7/32.png) [@flex727](https://boards.straightdope.com/u/flex727)\ **Post date:** [January 30, 2009, 11:25pm UTC](https://boards.straightdope.com/t/could-an-astronaut-fart-himself-back-to-the-space-capsule/483223/37 "2009-01-30T23:25:13Z")
> [@Icerigger](#): > > What is more important, the mass of the reaction mass or it’s exhaust velocity? Say an astronaut was trapped in the center of a huge open space in a vacuum and he took off his clothes which have a mass of 3 Lbs. He starts to swing the clothes in a circle as fast as he can and lets go. I assume he will move in the opposite direction of the clothes at some velocity, yes? If he just gently pushed the clothes away his delta-V would be much, much less, correct? Correct. It’s all about momentum transfer. Momentum is mass times velocity, so they’re equally important. ---
**Author:** ![trebor](https://avatars.discourse-cdn.com/v4/letter/t/85f322/32.png) [@trebor](https://boards.straightdope.com/u/trebor)\ **Post date:** [January 30, 2009, 11:58pm UTC](https://boards.straightdope.com/t/could-an-astronaut-fart-himself-back-to-the-space-capsule/483223/38 "2009-01-30T23:58:19Z")
I have actually done preliminary experiments in microgravity to determine if Diet Coke & Mentos could be used as an emergency rocket. [![](https://img.youtube.com/vi/P01kVKp6MIs/hqdefault.jpg "Diet Coke & Mentos in Zero G at 300 fps") ](https://www.youtube.com/watch?v=P01kVKp6MIs) My intuition is that the actual mentos effect wouldn’t help much because of the lack of convection in zero-g, but obviously uncapping a 2-liter bottle of Diet Coke in a vacuum is going to result in some propulsive ejection effects. I’d have to do some serious calculation to figure out if it would be more effective than just throwing the sealed bottle in the opposite direction. ---
**Author:** ![The\_Tao\_s\_Revenge](https://avatars.discourse-cdn.com/v4/letter/t/73ab20/32.png) [@The\_Tao\_s\_Revenge](https://boards.straightdope.com/u/The_Tao_s_Revenge)\ **Post date:** [January 31, 2009, 3:22am UTC](https://boards.straightdope.com/t/could-an-astronaut-fart-himself-back-to-the-space-capsule/483223/39 "2009-01-31T03:22:29Z")
> [@trebor](#): > > I have actually done preliminary experiments in microgravity to determine if Diet Coke & Mentos could be used as an emergency rocket. > > [http://www.youtube.com/watch?v=P01kVKp6MIs&feature=channel\_page](http://www.youtube.com/watch?v=P01kVKp6MIs&feature=channel_page) > > My intuition is that the actual mentos effect wouldn’t help much because of the lack of convection in zero-g, but obviously uncapping a 2-liter bottle of Diet Coke in a vacuum is going to result in some propulsive ejection effects. I’d have to do some serious calculation to figure out if it would be more effective than just throwing the sealed bottle in the opposite direction. I’d WAG it’d depend on your throwing arm, but as long as you’re not doping up on Bane level steroids opening the coke would give you more thrust. You’d not only have the pop carbon fizzing out but you’d have the liquid boiling. ---
**Author:** ![Hometownboy](https://avatars.discourse-cdn.com/v4/letter/h/5e9695/32.png) [@Hometownboy](https://boards.straightdope.com/u/Hometownboy)\ **Post date:** [January 31, 2009, 5:40am UTC](https://boards.straightdope.com/t/could-an-astronaut-fart-himself-back-to-the-space-capsule/483223/40 "2009-01-31T05:40:46Z")
And thats a great lead-in for the incomparable Poul Anderson novella, “The Makeshift Rocket” (Ace Double F-139 b/w Anderson’s “Un-Man and Other Novellas”). Here’s the blurb: > [@](#): > > Knud Axel Syrup, chief engineer of the spaceship _Mercury Girl_, sat and drank his favorite beer and thought about the war he was desperately anxious to avoid. The planetoid he was stranded on, Grendel, was occupied by a band of fiery Irish revolutionaries who weren’t loading their guns with shamrocks. And once the Anglians found out about the invasion. they’d make the legendary Donnybrook seem like a harmless Rugby match. > > When Herr Syrup shook up a bottle of brew and let the foam shoot out of its top, he knew what had to be done to get off Grendel. > > And so came about a marvelous spaceship, built of beer kegs, bound by gunk, upholstered with pretzel boxes and powered — for the first time in space travel history — by the mighty reaction forces of malted brew! I’m a klutz at physics, so cant speak directly to the situation, but I have read since that old hard SF Poul had it worked out in a plausible manner. It’s a fun read, too. [Previous page](https://boards.straightdope.com/t/could-an-astronaut-fart-himself-back-to-the-space-capsule/483223.md?page=1) [Next page](https://boards.straightdope.com/t/could-an-astronaut-fart-himself-back-to-the-space-capsule/483223.md?page=3)