Boeing’s Composite Tank Could Greatly Improve Launch Vehicles

One of the largest composite rocket propellant tanks ever manufactured is prepared for transport on NASA’s Super Guppy airplane. (Credit: Boeing)

One of the largest composite rocket propellant tanks ever manufactured is prepared for transport on NASA’s Super Guppy airplane. (Credit: Boeing)

HUNTSVILLE, Ala. (NASA PR) — For more than 50 years, metal tanks have carried fuel to launch rockets and propel them into space, but one of the largest composite tanks ever manufactured may change all that. This spring, that tank–known as the composite cryotank–is set to undergo a series of tests at extreme pressures and temperatures similar to those experienced during spaceflight.

“NASA focused on this technology because composite cryogenic tanks promise a 30 percent weight reduction and a 25 percent cost savings over the best metal tanks used today,” said Michael Gazarik, associate administrator for NASA’s Space Technology Mission Directorate. “It costs thousands of dollars to deliver a pound of cargo to space, so lighter tanks could be a game changer allowing rockets to carry more cargo, more affordably.”

Technicians prepare the 18-foot-diameter (5.5-meter) tank during manufacturing at the Boeing Developmental Center in Tukwila, Wash. (Credit: Boeing)

Technicians prepare the 18-foot-diameter (5.5-meter) tank during manufacturing at the Boeing Developmental Center in Tukwila, Wash. (Credit: Boeing)

The 18-foot-diameter (5.5 meter) composite tank just completed final assembly at the Boeing Developmental Center in Tukwila, Wash. Soon it will be loaded onto NASA’s Super Guppy, a large, wide-bodied cargo aircraft, that will carry it on a two-day journey to NASA’s Marshall Space Flight Center in Huntsville, Ala., where it will be filled with extremely cold, or cryogenic, hydrogen propellant and undergo a series of tests throughout the summer.

“Successful tests last year with an 8-foot-diameter tank gave us the confidence that we could build and test a much larger composite tank,” said Steve Gaddis, manager for Space Technology’s Game Changing Development Program. “This tank is the size of metal tanks that fuel full-size rockets today, so this is a true milestone in composite tank design and fabrication.”

A team of engineers from Boeing and NASA designed and manufactured the tank. NASA experts learned from prior tank designs and testing and helped devise ways to combat imperfections such as microscopic leaks, found in previous composite tanks. The team leveraged Boeing’s experience producing composites for aircraft to use a unique fiber-placement technique and new materials that did not require expensive curing processes in autoclaves, procedures traditionally associated with composite production.

A robot heats advanced composite materials to form the skin of a composite tank designed to hold super cold propellants. (Credit: Boeing)

A robot heats advanced composite materials to form the skin of a composite tank designed to hold super cold propellants. (Credit: Boeing)

“Advances in composite materials and manufacturing offer some of the greatest potential for improvements in cost, schedule and overall performance for a wide range of NASA missions,” said John Vickers, the program manager for the Composite Cryotank and Technologies Demonstration project at the Marshall Center. “We have improved composite manufacturing without adding risks or costs to any of NASA’s current projects. We want to advance this technology, so tanks are ready as NASA’s Space Launch System, the largest most powerful rocket ever built, evolves.”

When the tank arrives at the Marshall Center, it will move to a clean room and be prepared for testing at a recently refurbished test stand. Here, the tank will come to life as it is filled with liquid hydrogen, cooled and pressurized. As it undergoes this endurance testing, NASA and Boeing engineers will monitor data to see how it performs compared to metal tanks and the smaller 8-foot-diameter (2.4-meter) tank tested at Marshall last summer. Engineers will monitor testing from a new centralized control room, which is shared by several test facilities and has updated video, data acquisition and communications systems.

“Boeing and NASA assembled some of the world’s experts to design, build and test the tank,” said Dan Rivera, the cryotank program manager within Boeing Research & Technology, the company’s advanced research and development organization. “We used new composite materials and an innovative design capable of withstanding harsh launch vehicle environments. Both the approach and the technology for the design and manufacturing are revolutionary.”

For more information on the Composite Cryotank Technologies and Demonstration project, visit:

For more on NASA’s Space Technology Mission Directorate:

Marshall manages the SLS Program for NASA. For more information on SLS, visit:

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41 Responses to “Boeing’s Composite Tank Could Greatly Improve Launch Vehicles”

  1. 1 Christopher Miles

    Curious as to how this composite material/tank/process varies from that developed for the X-33 program. I seem to remember that just after that program ended(after the switch to Aluminum due to initial composite tank cracking) the issues surrounding the composite tanks had been solved.

  2. 2 Stuart

    Now that the composite tank problem is resolved can we resurrect the X33 program?

  3. 3 Eric Thiel

    I was thinking the same thing about the X-33, kinda makes you wonder if it could be possible now.

  4. 4 Malatrope

    I’m proud to say that I worked on this in a small way. I was unaware, despite that, that composite tanks weren’t “the norm” in today’s industry. Our managers kept us relatively naive — I think so that we’d work harder!

  5. 5 newpapyrus

    Might be the kind of light weight hydrogen tank the Brits could use for their SKYLON spacecraft.


  6. 6 windbourne

    Hmmm. How soon before it shows up in other launch systems such as SpaceX.

  7. 7 windbourne

    Of course that will not be needed until around 2025-2030.

  8. 8 windbourne

    That is where the tech came from.

  9. 9 windbourne

    This was resolved for the X33.
    And that was before cheney told L-Mart and USAF that they could not have it and then ordered the X33 dismantled

  10. 10 therealdmt

    The X-33 might have required non-cylindrical tanks to fit enough propellant and LOX volume within its body. If so, that might still be a bridge to far.

    That would be awesome though, if we could revive it!

  11. 11 therealdmt

    I wonder how reuseable these tanks will be. If reuseability isn’t a significant issue (and if there aren’t other show stoppers) and SpaceX puts tanks like these inside a Falcon 9R, one wonders just how low prices could go! Could be exciting times…

  12. 12 Hug Doug

    the X-33 had a lot more problems than just the fuel tank. the entire spacecraft was overweight and the center of gravity was way off as a result. it would never have flown as designed, with the composite tank or not.

  13. 13 Hug Doug

    the X-33 had a lot more problems than just the composite fuel tank. the entire spacecraft was overweight and the center of gravity was way off as a result. it would never have flown as designed, with the composite tank or not.

  14. 14 Hug Doug

    if the X-33 were redesigned and started -from scratch- today, it would probably be possible to build. the X-33 as it was built, was badly overweight and the center of gravity was way off, it would never have flown as it was designed to, which is why the program was cancelled.

  15. 15 Hug Doug
  16. 16 windbourne

    Reuse-ability is a good question.

  17. 17 windbourne

    Still, you have to love the engine on it.

  18. 18 Michael Vaicaitis

    ““It costs thousands of dollars to deliver a pound of cargo to space, so lighter tanks could be a game changer allowing rockets to carry more cargo, more affordably.”
    Is this an attempt to be deliberately stupid?. The reason it costs thousands of dollars per kg to orbit is because they throw away the entire rocket after only 1 use. It is not the mass of the tanks that is the inherent problem, it is the expendable design of the launcher.

    The Skylon design uses LH2 and LOX tanks that are NOT structural. In the Skylon, the tanks are suspended inside the airframe. Because Skylon breathes atmospheric oxygen up to 25km or so, it has a takeoff mass about 175 tonnes less than an F9 v1.1 for a similar LEO payload capability. Also, because it uses aerodynamic lift it only reaches 2g on ascent and re-entry. The benefit of this is much less structural loading on the airframe and even less on the non-structural propellent tanks. These composite tanks are an attempt to solve a problem from which Skylon does not suffer.

    The downside is that it will take 10-20 times as much to develop Skylon as compared to Falcon 9 and more than 10 times as much to manufacture each vehicle. If a Skylon can be 200 times, then a Falcon 9 used 20 times would still be cheaper; and that’s before you start to amortise in the development costs.

  19. 19 Hug Doug

    oh, yes. the work done on the XRS-2200 linear aerospike engines were by far the most impressive part of the X-33 project, they were a spectacular success in spite of being overweight.

  20. 20 windbourne

    Yeah, but I keep thinking that the weight could have been brought down. New metals. New design. Name it. Perhaps rather than a linear aerospoke, they could use a line of toroidal aerospike.

  21. 21 BeanCounterFromDownUnder

    Cost is the bigger question. SpaceX optimise for cost and effectiveness not just weight or efficiency. If metal tanks are less expensive (read easier to build) and do the job then that’s all they’ll aim for. BTW their interstage is carbon so they’re clearly open to utilising alternative materials.

  22. 22 BeanCounterFromDownUnder

    Why would they when they have all they need? Weight isn’t the issue, cost is. Besides, SpaceX use carbon construction already in the interstage sections.

  23. 23 Tonya

    This piece of research was to produce a liquid hydrogen tank, something which has particular technical challenges beyond existing composite designs. SpaceX may well use composites in the future, but they don’t use hydrogen, so have more options.

  24. 24 Hug Doug

    it was made of a new metal to begin with! they had to develop a new heat-resistant alloy for it, and the alloy was heavier than anticipated.

  25. 25 Aerospike

    Really? What Engine? Never head of it! :p :D

  26. 26 windbourne


  27. 27 BeanCounterFromDownUnder

    Elon doesn’t like hydrogen due to it’s tendency to break down metalic compounds which I guess would be one reason for going for carbon. Besides Mars is Elon’s goal and he’s counting on at least some ISRU hence his use of Methane for his next engines.

  28. 28 Tonya

    The problems are worse with composite materials, which was the point of this project. Hydrogen always wants to leak into the composite material (small atomic size), which leads to it delaminating.

    Elon cited multiple reasons including large volume, handling difficulty and cost. Ultimately saying that hydrogen and methane were near equal when all factors were considered.

  29. 29 BeanCounterFromDownUnder

    Hi Tonya. Thought he came down well and truly on the side of Methane but I don’t discount your stated reasons. Do you have a source for Eon on this?

  30. 30 Tonya

    From memory, the phrase he used was that it was a “shoe-in”. I would have to search to find the context for that.

    I’ve seen plenty of forum comments that talk about hydrogen as almost the worst fuel imaginable for all use cases, since SpaceX selected methane. The only thing I can remember Elon being critical over was its use as a first stage fuel because of the large tank volume. There’s sometimes a trend for “thing people think Elon said”.

    For upper stages or orbital transfer hydrogen is still the most powerful and the large volume is less of a problem.

    Ultimately, we of course know that Elon is interested in Methane for Mars ISRU. Others still believe Hydrogen extracted from water makes more sense for an in space industry. Time will tell who was right.

  31. 31 BeanCounterFromDownUnder

    All to true. Time will tell. One other thing I seem to recall is that Methane and Lox have similar liquid operating temperatures which I believe makes life easier when designing an engine to run on those fuels.

  32. 32 Snofru Chufu

    Yes, higher Isp of LOX/LH2 is compensated by much lower structural weight LOX-RP1, if you compare for example the ideal velocity change, which can be made by Falcon 9 in vacuu with that of Delta-IV ‘s single module velocity change.(without a payload).

  33. 33 Snofru Chufu

    I assume that aerodynamic loads onto Skylon are much greater (!) as in case of Falcon 9, because it flight through atmosphere deeper and longer and what is most important with a significant large angle of attack (to use wings to the lift the vehicle).

  34. 34 Michael Vaicaitis

    Liquid CH4 -161 C, LOX -183 C, LH2 -253 C.

    A few of the main advantages of CH4 over LH2 :
    - CH4 is much cheaper than LH2, which when factored into the costs of a reusable booster becomes more important.
    - the energy costs of manufacturing, cooling and storing liquid CH4 on Mars are lower than LH2. The chemistry itself via sabtier (Zubrin has championed this for years) provides most of the energy – this is probably a biggy from a Musk/Mars perspective.
    - there are no long term storage issues and like LH2 leaking mentioned in previous posts

    - CH4 eases boil-off issues in space (may or may not be an issue)
    - LH2 can burn invisibly
    - although a CH4 booster will be heavier, because, the fuel is more dense, the tank and thus the rocket will be smaller, which leads to a manufacturing cost advantage
    - CH4 and LOX can be (relatively easily compared to LH2) super chilled to reduced the volume further and get even more fuel in a given tank size/mass. I think SpaceX I already planning this technique to load more LOX into F9R and eke a bit more performance.
    - in space the vehicle will be less massive, so you can compensate for the performance disadvantage by taking extra fuel.

    Looking at a longer term Earth-Mars transport, I don’t see that manufacturing propellent in space will have any advantage over electric propulsion….”time will tell”.

  35. 35 Michael Vaicaitis

    The aerodynamic loading may be greater, I could not say for certain. But the accelerative loading is less. The high speed air breathing part of the trajectory (reaching Mach5.5ish) will be fairly high where the air is thin. Although it may spend more time in the atmosphere, because the ascent angle at “low” altitudes is quite shallow, the peak loadings will be relatively benign. Once it reaches about 25km it switches to on-board LOX and ascends more steeply but only at 2g acceleration. Because it has reached Mach 5.5 with full LOX tanks it can still reach orbit at a relatively low 2g acceleration, which means the dry vehicle can be kept as light as possible. It stills weighs 55 tonnes which is twice that of an F9.

    In the lower atmosphere it doesn’t need to go too fast to generate lift, but higher up it must go faster to generate the same amount of lift. But the aerodynamic loads are only a function of air density and speed.

    F9 reaches maxQ at only 1000mph. Even though it’s speed increases, the air density also decreases.

  36. 36 Snofru Chufu

    Another issue: Weight saving is important, but the impact of tank mass for a pump-fed vehicle on total structural mass shall not overestimated. In case of S-IC (Saturn-V) tank mass contributed only 20-25%.

  37. 37 windbourne

    I wonder if the fabric in Bigelow’s units can handle -200C?
    It would be interesting to use those as tanks in space. With the heavy insulation, it might be able to keep things very cold.

  38. 38 Tom Billings

    Most of the mass of the Bigelow units’ skins is there to keep *gas* inside, and meteoroid fragments *outside* the living space. That means they are built *very* differently than a tank for any *liquid* propellant. The lower the temperature, the less flexible most things are. A kerosene tank you wanted to fold up before using it, …maybe, but most LOX/Kero is burned in first stages. So, I doubt anyone would bother.

  39. 39 windbourne

    I was thinking more of a fuel depot.

    I realize that BA’s units are meant for fairly inert gas, but I just wonder if a lightweight liner can be used inside of this that will deal with the temps and the liquids.
    The liquid methane should be fairly inert, but I have not dealt with LOX (just liquid helium, which is inert, but hard on the metals).

    The advantage of this is that having one basic unit type for handling humans, fuel, perhaps water, would make a pretty useful fast way to get depots up there, quickly and cheaply.

  40. 40 Christopher Miles

    Clarification: I was not referring to the X-33 space plane itself, I was really interested in the composite tank tech. Is this Boeing tech new, or is it on offshoot of what was learned 14 years ago? Looking at the comments- it seems I wasn’t the only one to be reminded of the previous program.

  41. 41 Hug Doug

    ah, i see. IIRC after the X-33 program was cancelled, the lobed composite tank was “completed” such that it did not fail under pressure testing, it was still overweight though.

    my guess would be that the process is different, just due to the simple geometry of this large tank.

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