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Exploration

Composite Cryogenic Tanks Test Successful

By Marc Boucher
NASA Watch
July 2, 2013
Filed under

NASA Tests Game Changing Composite Cryogenic Fuel Tank [Watch] NASA Marshall
NASA recently completed a major space technology development milestone by successfully testing a pressurized, large cryogenic propellant tank made of composite materials. The composite tank will enable the next generation of rockets and spacecraft needed for space exploration.
… “These successful tests mark an important milestone on the path to demonstrating the composite cryogenic tanks needed to accomplish our next generation of deep space missions,” said Michael Gazarik, NASA’s associate administrator for space technology at NASA Headquarters in Washington. “This investment in game changing space technology will help enable NASA’s exploration of deep space while directly benefiting American industrial capability in the manufacturing and use of composites.”
… “The tank manufacturing process represents a number of industry breakthroughs, including automated fiber placement of oven-cured materials, fiber placement of an all-composite tank wall design that is leak-tight and a tooling approach that eliminates heavy-joints,” said Dan Rivera, the Boeing cryogenic tank program manager at Marshall.

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21 responses to “Composite Cryogenic Tanks Test Successful”

  1. TheBrett says:
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    If it gets the weight and cost down, then that bodes very well not just for regular launches, but for any propellant storage and in-orbit refueling set-up down the line (lower price to send stuff into orbit).

    • Steve Whitfield says:
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      I didn’t see anything in the text about leak rates. So, while this may be a gain in terms of reducing the mass of a LV, it may not have the necessary performance for storage, especially in space. And in-orbit refueling may only have a short window, depending on the leak rates.

      • dogstar29 says:
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        Boiloff rates, please. A “leak”, even if small, is an unplanned loss of fluid due to a failure of containment. There is a fair amount of work on zero-loss cryo tankage using a combination of insulation and active cooling. Although composites provide some intrinsic insulation, sealing a tank for prolonged storage of LH2 would certainly need multilayer insulation or something similar, and active cooling to eliminate the remaining boiloff. The insulation layer is typically separate from the structural/fluid sealing layer, which was under test here.

        • Steve Whitfield says:
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          I’m talking about leakage (the recognized industry term), separate from any other consideration, including temperatures. The hydrogen atom (and the H2 molecule) is smaller than any other element, therefore hydrogen will “leak” from a tank made of any normal physical material. Adding more insulation and cooling may slow this down somewhat, but the simple fact is that the hydrogen permeates the tank shell material(s) and eventually makes its way out of the tank and into ambient space — it moves from the area of high pressure to the area of low pressure. Even at the lowest of cryo containment temperatures this will be true.

          This problem is separate from the cooling issues and has to be solved as well. It may, in fact, be the hardest problem to solve if we want long-term storage depots.

          • EarthlingX says:
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            If problem is with hydrogen, then don’t use it, or don’t store it in hydrogen form, but in some compound form which allows simple generation.

            I don’t think oxygen has as much of a problem with leaking/boil off.

          • Steve Whitfield says:
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            Agreed. Oxygen has the same problem, but to a much lesser extent (being a larger atom/molecule). The oxygen leakage rate over days and perhaps weeks can probably be lived with at its current value for many jobs.

            The thing with LH2 is that pure cryo hydrogen is by far the most efficient fuel available for rocket engines. Using anything else gives significantly less thrust per unit volume, which is why hydrogen’s been used despite its difficulties.

            Hydrogen in a compound form is not the same thing, since considerable endothermic reaction (therefore energy input) is required to “peel out” the pure hydrogen, which is the only fuel with the high ISP/thrust possible. Also, loading a hydrogen compound greatly reduces the volume available and mass fraction (efficiency) for the actual hydrogen, making the package much less efficient.

            Realistically, if most (or even all) of what we propose were viable ideas then the people in the field working this stuff every day would have thought of them long before we did. But I think working through these ideas for ourselves, even the ones already dismissed, is time well spent for us in understanding the details of the situations that need to yet be solved.

          • EarthlingX says:
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            No argument about Hydrogen being the most efficient fuel for combustion rocket engines, but spacecraft is not only engine and at the end, systems for keeping H cool can add plenty to the final mass and ruin pretty isp calculation.

            Another reason for not using H is also it’s rather big volume, which translates to more atmospheric resistance in the thickest part, adding to loss of whole system performance.

            One of the alternatives i was hinting at is UDMH
            http://en.wikipedia.org/wik
            as an example. That seems to work just fine too. For in-space there’s other engines, with Isp starting at 4-5 times best LH/LOX engine.

            All of the above and more is hopefully taken into consideration, but those who decide on the final design might have different criteria.

            I wouldn’t be so worried about non-expert discussing technical stuff. Some of us have better understanding of tech than average journalist writing on the topic, with rare exceptions. Most of them would benefit just from reading a couple of wiki articles, which i doubt they ever will.

            You can find better argument.

  2. hikingmike says:
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    This is damn cool stuff. I guess Boeing is getting to put to use their composite expertise in more areas after their work on the 787 as they should.

    • dogstar29 says:
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      There is some relationship, but the main challenge in LH2 compatible composites is avoiding the permeation of liquid hydrogen into the composite, where rewarming causes expansion of the liquid hydrogen into gas, forcing apart the composite layers.

      I also feel the phrase “game-changing” is vastly overused and inappropriate hype, but nowadays even the RFPs demand “game-changing” technology. Do we even remember what the game is?

      The X-33 failed because NASA could not build a workable composite LH2 tank for it. Perhaps as an explanation for this failure, the claim has long been made that because NASA could not do it, it must be impossible, or at least extremely difficult. In reality, as ReusableForever points out, composite cryo tanks are an evolving technology, and this test is slightly ahead of previous composite LH2 tank tests that have been gong on for over 20 years. This won’t “change the game” and make SSTO practical or human spaceflight cheap. If applied to a launch vehicle it will, like aluminum-lithium alloys, save a little weight and thus increase cargo capacity. It is one small step, and small steps can add up.

  3. korichneveygigant says:
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    didnt the X-34 have a composite tank also? But I dont think that one was cryogenic

  4. Mark Friedenbach says:
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    Can we have our X-33/VentureStar back now, please?

    • dogstar29 says:
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      The central problem with X-33 was not failure of cryo tank (an aluminum tank would actually have been lighter). It was the arbitrary requirement for reusable SSTO performance, which was not possible with the technology under test and has little bearing on overall cost.

      So what, exactly, was this tank made of, and did it use a metal liner?

    • ReusablesForever says:
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      The Venturestar as an SSTO was dead on arrival. They absolutely forgot the prime directive for SSTO design: keep the weight out. Note to Vulture4 also: The [then] Rockwell-proposed version could have made the mission and verified the design and manufacture of an LH2 composite cryo tank (no liner) in tests at MSFC back in 1996!

      • dogstar29 says:
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        It was my understanding (I could be wrong) that the failure of the X-33 tank was largely to its complex lobulated shape, which was inappropriate for composite design, rather than the use of composites per se, and that Rockwell proposed an aluminum tank which (because of the shape problem) was actually lighter, but that this was rejected by the NASA program manager because he believed that the weirdly-shaped composite LH2 tank, although not really needed for the suborbital X-33, was essential for SSTO and that without SSTO the program was worthless.

        It was my impression that all the composite cryo tank tests that have been successful to date, including at least one linerless LH2 tank, have used simpler cylindrical designs.

        • ReusablesForever says:
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          Well as I mentioned, the prime directive for SSTO design is to keep the weight out. The lobed tank adds weight and was used to maximize internal fuel volume of the inefficient shape. The Rockwell design incorporated cylindrical tanks which doubled as primary structure. Both tanks were to be composite but, for the X-33, the LO2 tank was aluminum, to be replaced in the full scale RLV when technology caught up.

          See my paper “Why the X-33 VentureStar Gave SSTO a Bad Name.” AIAA paper 2009-6456

  5. dogstar29 says:
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    The DC-X had a cryogenic composite tank, and despite cancellation of the X-33 a simplified composite LH2 tank prototype was successfully tested at the end of the program. Unfortunately these programs were derailed by problems at the program level and lack of interest in reusable launch vehicles.

  6. Saturn1300 says:
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    Another fuel is hydrazine. NASA has a replacement for it. Non toxic, more efficient. A longer burn time with the same size tank. Made from Ammonium Nitrate. The problem is that it burns hotter and needs a new engine. They will fly it in a few years. When SpaceX adopts this tank, then I will believe it is cheaper.

    • dogstar29 says:
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      However this only really impacts hydrazine monopropellant systems; bipropellant systems need an i and would presumably still use toxic nitrogen tetroxide.

  7. Steve Whitfield says:
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    This is presented as a joint NASA-Boeing project, but who owns the process/technology? If Boeing owns the patent(s) then it’s not as big a deal for the industry as a whole as it would be if NASA controlled it.

  8. Andrew_M_Swallow says:
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    I hope they remember that landers also need light weight fuel tanks.