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When the Washington State University researchers looked through the literature, they came across research that described the development of a bellows that took advantage of origami, the Japanese art of paper-folding. The research discussed applications relating to medical stents, or even deployable solar sails for spaceflight — but Westra and his colleagues adapted the design for rocket fuel bladders

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2020 https://www.geekwire.com/2020/ancient-art-origami-provides-pathway-building-better-tank-rocket-fuel/

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  • $\begingroup$ I removed this paragraph from my article because, from general engineering, I did not understand how inflatable fuel tanks are supposed to work in space. But maybe I am missing something and it does make sense after all? $\endgroup$
    – TheMatrix Equation-balance
    Jan 24 at 17:34
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    $\begingroup$ Tanks with bladders are pressurized with some pressurant gas, which is outside of the bladder but inside the tank. The propellant is inside the bladder. When the propellant valve is open the gas forces the propellant to leave the tank. They've been used for quite some time. $\endgroup$
    – David Hammen
    Jan 24 at 18:18

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The basic concept of a bladdered tank is that the bladder makes it so that only propellant leaves the tank and so that propellant can be used even under zero g conditions. Compare with a bladder-free tank that requires settling burns and/or propellant management devices. There are advantages and disadvantages to the two tank designs (bladdered vs bladder-free).

Except in the case of a bladder failure, there is no chance of pressurant gas leaving the tank. (Bladder failure is generally catastrophic.) Bladdered tanks can also result in pockets of trapped and hence unusable propellant. The bladder can also be a mass penalty.

Bladder-free tanks can result in pressurant gas leaving the tank, and that can be catastrophic. The settling burn requires yet another set of thrusters. This adds complexity and adds failure modes. Propellant management devices have their own multiple failure modes. It's a pick your poison type of situation.

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  • $\begingroup$ "David Hammen" - Thank you! Your answer has added some clarity to me. What I am still missing is a difference when you talk about fuel tanks on a launch pad where the time of cryogenic fuel in tanks counts on minutes - vs - fuel tanks in inter-planetary space where time is count on years. $\endgroup$
    – TheMatrix Equation-balance
    Jan 24 at 18:18
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    $\begingroup$ @TheMatrixEquation-balance I did not mention launch vehicles in my answer. Bladdered tanks are typically used for on-orbit or in-space ops for RCS thrusters. Launch vehicles don't need them. A bladder is just an added complexity for launch vehicles. RCS thrusters on the other hand are often called upon the provide thrust in zero g situations. $\endgroup$
    – David Hammen
    Jan 24 at 18:22
  • $\begingroup$ "David Hammen" - From your personal view, do you think SpaceX Starship Interplanetary - will use bladdered tanks ? $\endgroup$
    – TheMatrix Equation-balance
    Jan 24 at 18:34
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    $\begingroup$ @TheMatrixEquation-balance There's no telling. SpaceX is constantly redesigning. They build a little, test a little, redesign, and then do it all over again. They have adopted Agile. That's praise rather than a jibe, by the way. It does however drive NASA crazy. $\endgroup$
    – David Hammen
    Jan 24 at 18:48

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