We are used to “aerospace” sounding like almost futuristic materials. Titanium, high-strength aluminum, carbon fiber, alloys designed to withstand extreme conditions. The technology industry itself has turned that idea into a sales argument: just remember how some laptops and cell phones They boast of using “aerospace grade” materials.“to convey lightness, resistance and precision. That is why what happened this week during a visit to the Airbus facilities in Getafe caught my attention. In front of one of the pieces, Veronica Villanuevaresponsible for Manufacturing, Assembly, Integration and Testing at Airbus Space Systems in Spain, pointed to a yellowish surface and said it bluntly: “What you see here is yellowish, this is corkit is the thermal insulator that is put on, it is super curious, right?”
The phrase had some revelation, but it was not an anecdote for visitors. The cork was there for a very specific reason: a launcher must not only be able to take off, it also has to protect its structures in a very demanding physical environment. In this case, Villanueva was talking about pieces linked to the Ariane 6. We are not talking about an “Airbus rocket”, but rather a European launcher in which ArianeGroup occupies the central role and Airbus participates by manufacturing several structures and key elements.
The cork we saw in Getafe shows that space engineering also has very everyday surprises
To understand why this detail was so striking, it is worth taking a step back in manufacturing. Before reaching the cork, many of these structures go through a process based on composite materials, especially carbon fiber and fiberglass. Villanueva explained during the tour that the carbon fiber used in the plant arrives as a prepreg material, that is, already mixed with resin. From there, the machines place layers on a mold until the desired geometry is built. Then will come the curing, the inspection and everything necessary to turn that stack into a piece capable of being part of a launcher.
The underlying reason is easy to understand: in a launch, every kilo counts long before reaching orbit. A launcher must lift its own structure, its systems and the load it carries, so any weight savings can have significant consequences. The manufacturing manager defended during the tour that composite materials are especially interesting due to their low mass, their tensile strength and their ability to adapt to changes in temperature. The downside is that they are not as simple or as cheap to manufacture as metal.
View of the Airbus production area in Getafe, where some structures linked to Ariane 6 incorporate cork as part of their thermal protection
That complexity appears as soon as the structure begins to take shape. After taping, the pieces go through an autoclavea type of large pressurized oven where temperature and pressure are controlled so that the resin solidifies and the whole is compacted. Villanueva explained that the process includes a vacuum bag to extract any air that may have remained between the layers, an important detail because possible defects are not always visible from the outside. In a composite structure, what happens on the inside can be as relevant as the exterior geometry.
Verónica Villanueva, responsible for Manufacturing, Assembly, Integration and Testing at Airbus Space Systems in Spain
And then, after all that chain of carbon fiber, resin, pressure, vacuum and inspection, the least expected material appears again. Cork is applied to certain areas of the structure as a layer of protection against heat, but not in any way. Raúl Medina, head of launchers at Airbus Space Systems Spain, pointed out the pieces during the visit and gave a very specific measurement: “We can go from 2 millimeters to 5 millimeters thick.” On the indicated pieces, that layer moved within a very specific margin.
Detail of an Ariane 6 part manufactured by Airbus in Spain. The light areas show the cork applied as thermal protection; the dark ones, areas without that coating
The decision is not made by eye either. Medina summed it up with a very graphic phrase: “This in the end is an art. There are thermal engineers who analyze that you will be exposed to more heat and then, depending on that, more thickness, less thickness or areas without cork“On the surface of the piece, this thermal reading translates into areas with more protection, others with less and others where the material from the cork oak is not directly applied.
Raúl Medina, head of launchers at Airbus Space Systems Spain.
The idea may sound strange, but it does not appear isolated in the European space industry. In another application, ESA explained it with the Qarman CubeSatdesigned to study atmospheric reentry: its nose was made of cork, although not the kind we find in a champagne bottle, but of an adapted aerospace variety. The difference is in the behavior of the material when heated. First it swells, then chars, and finally flakes off, taking some of the unwanted heat with it.
Detail of an Ariane 6 part manufactured by Airbus in Spain. The light areas show the cork applied as thermal protection; the dark ones, areas without that coating
The supplier’s lead pointed in the same direction. Villanueva pointed out during the visit that that cork came from Portugal, and Medina added that whoever supplies it to the aerospace industry belongs to the same industrial universe that we associate with the wine and champagne corks. In open sources, that description fits Amorim Cork Solutionspart of the Portuguese group Corticeira Amorim, one of the world’s greatest names in cork. The ESA, in fact, identified Amorim as a supplier of the aerospace variety used in Qarman, although Airbus did not detail there the specific supplier of the parts before us.
One of the fascinating things about the space industry is that it always holds some surprises. We can imagine it as a territory dominated by advanced materials, highly controlled processes and pieces designed to the limit, and to a large extent it is. But it is enough to get close to an Ariane 6 structure in a plant in Getafe to discover that not everything corresponds to that image of technical sophistication. Sometimes, between carbon fiber, autoclaves, ultrasounds and thermal analysis, a much more everyday material appears. In this case, cork.
Images | Michelle Brittain | THAT | Xataka
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