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Yes, I spelled it “pee” shooter. Behold the glassy winged sharpshooter (link), a bug that can fling drops of urine from its anus at remarkable speeds, boasting accelerations 10 times faster than a Lamborghini.
Small spacecraft could carry plants and zillions of critters feeding on them, in a chamber
from which they can expel their pee as reaction mass. Based on nothing at all, my intuition says en masse they could synchronize their excretions the way fireflies sync their flashes.
Not sure if it’s scalable though. I wonder how many bugs would you need to match a Falcon-9 thrust? That might take some gnarly math to figure out.
Glassy-winged sharpshooters …
https://arstechnica...with-anal-catapult/
… fling pee bubbles with anal catapult [a1, Mar 01 2023]
More about super-propulsion
https://physics.aps.org/articles/v10/97
"... the effect could be useful for saving energy in technologies that involve propulsion of soft or fluid objects. For slingshots, archery, and catapults, only part of the initial elastic energy is transferred to the projectile. We could significantly increase the energy transfer by accounting for the deformation dynamics of the projectile or the acceleration dynamics of the projecting engine ... the same principles could also apply to elastic systems that launch aircraft from ships." [a1, Mar 01 2023]
Scaling graphic of urination across animal kingdom
https://arstechnica...-thats-kinda-weird/
[a1, Mar 13 2024]
https://en.wikipedi...g/wiki/Ion_thruster
[hippo, Mar 13 2024]
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Of course I read about it in Arse-Technica. |
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That pun should be an executable offense. |
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Re the idea, the biggest problem I see with it is finding a suitable plant type that keeps the bugs fed and grows back at an equal rate to that at which it is consumed, as well as how to carry enough water and fertilizer for this to be sustainable. |
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How will you keep the bugs alive in space? |
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[21_Quest], if that’s the biggest problem you can find you’re not trying very hard. But yes, the entire idea is impractically half-baked. |
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Partly because I thought the article was interesting, and also for opportunities to make execrable puns. |
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// (puns) Consider them execrated // |
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And nobody has even brought up the first flight test yet, to Uranus. |
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See second link, on super-propulsion. That was really the science I was interested in. |
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It's not rocket science (or even remotely like the pee shooter rocket), but still... someone already did think of applying this principle to throwing things faster and more efficiently. I don't know about aircraft launchers, but maybe a lesser , more grounded application... |
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Pellet guns? Water pistols? |
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Wha, you mean nobody else here needs to brace themselves at the urinal when they take a whiz? |
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This both wouldn't work, and is also baked. The problem with propelling anything out of the back of a spacecraft in order to make the spacecraft accelerate forward is that you have to carry that ejection mass with you on the spacecraft. Therefore to reduce the amount you have to take with you it's necessary to increase the ejection speed as much as possible to make it viable. The way this is generally done is with ion thrusters, which emit ions at (see link) 20–50 km/s. Low speeds (only "10 times faster than a Lamborghini") are useless for this. |
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// This both wouldn't work, and is also baked // |
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I see what you did there. |
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Of course it wouldn't work, I was aiming for silly. But that's a matter of scale. *Any* system (even ion drive) that has to carry its own ejection mass and then fling it away is silly. Light sails and Bussard scoops are only a little better. Until you can tug on the fabric of spacetime itself, you're stuck pretty close to the planet you came from. |
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Not quite - if you eject the mass fast enough (to make the tiny mass you're ejecting work hard for you), ion drive propulsion has the potential to be more sustainable if your spacecraft has a huge scoop on it to gather up stray atoms of fuel from interstellar space. Only 'potential' though - it's all a bit unproven |
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