Robotic Intestine for Continuous Rocket Propellant Mixing


Lorenzo von Matterhorn
Jan 31, 2009
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Not useful for hobbyists, just a strange bit of new propellant manufacturing tech. Also, about the title from the IEEE site, not rocket "fuel" if correctly named and not properly called "puking" since it simulates an "intestine".

Watch This Robotic Intestine Puke Rocket Fuel
The Japan Aerospace Exploration Agency may start to manufacture solid rocket fuel with puking robot intestines
26 Mar 2018

The idea is to turn the solid rocket fuel manufacturing process into a continuous operation rather than a discrete one, replacing rocket fuel mixing bowls that give you fuel in batches with a system that can just continuously pump out fuel instead. It’ll be more efficient, safer, and easier to scale, helping keep solid fuel rockets competitive for small satellite launches.

The stuff coming out of the machine represents a rubbery mixture of ammonium perchlorate powder (an oxidizer), aluminum powder (a high energy fuel), and an elastomer binder consisting of hydroxyl-terminated polybutadiene (HTPB). Generally, mixing these things together is done in what look like industrial bread dough mixers, which allows each batch to be carefully controlled to make sure the fuel comes out just right. Also, when you’re mixing up something designed to be more or less as explosive as possible, you want to do it very, very gently.

A peristaltic pumping system is able to mix ingredients both safely and effectively. It works just like your intestine does, with rhythmic contractions moving stuff along a tube, except unlike your intestine, the system is closed at both ends and the stuff is added in the middle, along with pressurized air. As the sections of the tube expand and contract, everything inside gets mixed together. An operational system would likely consist of a long mixing loop that would continuously ingest raw rocket fuel ingredients at one end, and then, er, expel them all mixed together at the other.

Once the fuel has been mixed, it’s poured into whatever shape you need it to take (lots of interesting options here) and cured into a rubbery solid. While the stuff in the video (which was associated with a media event, it looks like) is simulated propellant for safety reasons, this system has successfully mixed real propellant as well, which the researchers fired off in a benchtop rocket test just to make sure that it worked (it did).

The technical paper, properly named:

The Continuous Mixing Process of Composite Solid Propellant Slurry by an Artificial Muscle Actuator




Well-Known Member
Jan 20, 2009
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Glendale, AZ
We had a salesman show a similar system but not continuous, refered to as a stomach.
It was small, maybe do 100 gms, and really expensive.
We were willing to try it but nothing on it was explosion proof.


Well-Known Member
Nov 29, 2009
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How many pictures do you need of something ooozing out of a machine. Those fer-to-graph-ers were machine gunning that to death.