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NASA's John Vickers talks about the future of composites in aerospace
John Vickers has been with NASA for over 20 years and worked within the aerospace industry for almost 30 years. As manager of NASA’s National Center for Advanced Manufacturing, he has worked on many projects utilizing advanced composites, including presently a new larger space launch vehicle, and participated in several national projects with NASA, industry leaders, academia, and other government agencies.
Describe what your department does. How is it organized?
The Marshall Space Flight Center is one of ten NASA Centers throughout the nation. I work in the engineering directorate and within the Materials and Processes Laboratory.
What is your R&D like?
Within NASA there are ten levels that measure technology maturity called Technology Readiness Levels, which guide the insertion of R&D into a project. Level 1-3 consists of basic research levels, 4-6 are more advanced development and above six are technologies that are very advanced but still need some work to be inserted into a project. Within my organization we perform mostly level six or higher projects and our primary focus is on the technology challenges for propulsion and launch vehicles at the Marshall Space Flight Center.
What prompted NASA’s use of composites on a larger scale?
We’re in the planning and early design stages for very large structures and associated technologies related to NASA’s Ares V cargo launch vehicle. The structure is 10 meters in diameter, which is larger than any composite aerospace structure to date. To address these technology challenges, NASA has initiated the Advanced Composites Technology Project.
How and when do you use outside suppliers?
When we begin a project, I think many people believe we are looking for that Eureka moment. Yet in reality we utilize a great deal of existing technology and we perform much of our own research and perform sophisticated experiments in-house. But sometimes we don’t have the materials or processes we need, so we must invent them. We start with a concept or design and then determine if we want to do it in-house or contract it out, which is determined by what is available and who’s best suited within NASA or outside within the industry base.
How do you determine which suppliers to use?
We work through our prime contractors, who help us reach down into the industry to find the right companies. But we never want to lose visibility of the whole picture. We look at past performance, their production capability and cost.
Over the last several years our supply chain has continued to shrink. We are a lot like the rest of the nation in terms of manufacturing; our industry base is shrinking because of market forces, consolidations, and lean manufacturing and a just-in-time supply base.
How does your lab determine what parts will be made of each material?
There is a set of requirements we receive during the design phase, all of which are analyzed in different aspects through the life cycle. Major material decisions have to be made early in the design phase. We need to know dimension and weight requirements; if it’s a stiffness-driven structure, then what are its loads for compression and tensile properties, and of course what are the cost and sustainability factors?
When are composite products used?
In aerospace, composites products have advantages in both thermal and lightweight structures applications. Thermal applications include ceramic matrix or carbon-carbon composites, used in high temperature areas such as a nose cone, leading edge, or re-entry heat shield. Structural composites are much more widely used and have been around for 40 years. Very little progress was made in the first 20 to 30 years, it’s only been in the past 20 or so that I’ve seen signs of substantial progress. A lot is currently being done with composites in the structural components of aviation and aerospace, such as the Boeing 787 and NASA’s new all-composites crew module.
What is NASA’s material evaluation and testing processes like?
The materials and testing process we perform are extremely technical and rigorous. The R&D phase for something like a composite part is driven by the systems levels. We make decisions early on in the process and determine what we use and how long it will take NASA to incorporate the part into our systems, which can take one to five years. At the end of the R&D process, we perform the qualification and certification for space flight. If the space flight involves humans, then the qualifications are even more rigorous.
Why has it taken people so long to adopt composites?
I would say it’s a cultural phenomenon. People only use what they know and the aerospace community especially tends to rely on conservative materials that are proven to have a high level of confidence and reliability. It takes time to change, and the biggest project driving that change today is the Boeing 787.
What current concerns do you have regarding composites?
I think we are at a tipping point in the nation’s industrial base capability for composites. There are some perceptions that we are falling behind especially in Europe. One of the most important issues we are concerned with is the future workforce and skills that workers have coming from universities. We can’t solve this problem on our own, so we work very closely and combine resources with other agencies, such as the Department of Defense, to encourage manufacturing R&D.
What would you suggest to rectify that problem?
Focus on the workforce and programs to improve STEM (science, technology, engineering, and math). If we can do more in education and within academia to get those students in undergraduate and graduate programs to work in this area, when they enter the work force they will utilize composites more because they have the experience. My kids are more adept at using iPhones and laptops than I am, and it’s the same with composites. We have to make composites mainstream.
What performance properties would you like to see improved in composites materials?
When we talk about large scale composite structures, which are of primary importance to us, it is the issue of manufacturability. We are now looking at 10-meter sized sections of structure and we need to see the materials and processes improved. One problem is the time it takes to manufacture. Because it takes a great deal of time to apply layer after layer, that affects cost and performance.
In general we need to continually enhance our abilities in analysis, design, materials, manufacturing, test, and verification. One key area from a very technical engineering viewpoint is that we need to work on improving performance and understanding of damage tolerance, fracture, and fatigue.
What do you see as the composites industry’s greatest weakness?
I would have to go back to the culture and experience issues; it’s a road block in composites adaptation. Before the use of composites as a primary airframe in Boeing, composites were only used as a secondary structure. Part of that is what we at NASA are dealing with, which is a lack of composites knowledge and experience.
How do composite applications and products differ in aviation and aerospace products?
One of the primary differences is the life cycle of the components. For example, the structure of commercial airplanes has a life cycle in the 100,000 range. But in space, that is not the case. Our launch vehicles may be used only once. Also, in regards to manufacturing, the aviation production rate is much higher; they are in the thousands whereas we might produce four to six vehicles a year.
What do you do with composite products once the life cycle is complete?
We are very sensitive to the environment. NASA is in transition right now away from our current fleet of vehicles. What we do in manufacturing and reuse and recycling is a consideration in our new designs because obviously we want to strive to improve our environmental footprint. The green part of recycling composite parts is something NASA is continually working on together with industry, academia, and the Department of Defense.
What are parts that could be made of composites that currently are not?
NASA is considering designs using much larger launch vehicles, which right now are mostly made of aluminum. There is a lot of potential to use composites in the main structure and we are working hard to accomplish this. There is also potential to manufacture composite liquid oxygen and hydrogen cryogenic tanks that are used during a launch. Although there are no current plans to create those, nevertheless it would be a tremendous weight savings.
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