You will not be surprised to hear it, but rocket fuel is dangerous stuff. It's strong and volatile, which means it can explode before it gets into the rocket. This makes it difficult to produce because you have to mix certain materials, but overturn them too hard and they'll get their job done early. The solution? Well, scientists from Japan suggest puking robots.
In the above video (discovered by IEEE Spectrum ) you can see prototypes of engineers from Chuo University and Japan's National Aerospace Agency (JAXA) mixing solid rocket. It's basically a series of connected pipe segments that move back and forth like a worm. This movement mimics how our gut and esophagus move food around our body ̵
Normally, rocket fuel is produced in huge industrial mixers that work just like kitchens with rotating blades. But peristalsis instead of these rotational forces is gentler and would allow fuel to be produced in a slow, continuous process rather than in batches. Ingredient ingredients are added at one end and the final product is slowly transferred from the other before being allowed to dry to a solid. This, say the Japanese researchers, could prove to be safer and more efficient than the current method.
According to Evan Ackerman IEEE Spectrum the white Gloop shown in these videos are simulated fuel (for safety reasons), but researchers have used their robotic arm to produce real fuel in real ones Rockets tested. So, yes, these robots can puke well. To learn more about the dangers of making rocket fuel, you should read this 1966 NASA video, which graphically illustrates what happens when something goes wrong.