More missions heading for space need advanced materials

Space has long been considered the next frontier. But it’s time to retire that moniker based on all the activity going on outside our atmosphere. We’re seeing megatrends in action – from advanced sensor technologies to communications capabilities to asteroid mining and space tourism — all of which have economic impacts that suggest viable growth.

SCHOTT has been supplying the U.S. space program for more than 50 years. Our materials have been involved in dozens of historic missions, most notably with our optical glass used in both the Westinghouse lunar TV camera and Hasselblad camera when Apollo 11 touched down on the moon in 1969.

Most recently, ZERODUR^®, our low thermal expansion glass-ceramic, was used as mirror substrates for the DRACO imager to guide the spacecraft and provide hi-res images on NASA’s DART mission. The last images seen before impact with the asteroid were enabled by SCHOTT glass-ceramic. ZERODUR has been around for more than 60 years and is still a reliable material due to its special properties that enable precise positioning and imaging.

As we push the limits of what’s possible in aerospace, engineers need to consider new materials that can withstand harsher conditions than ever and meet demanding applications. SCHOTT has developed a porous material with rigid amorphous microstructures that offer robust mechanical, thermal, and chemical resistance.

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CoralPor^® is a porous material with high specific surface area. Utilizing it in composites highlights its versatility and expands its potential to limitless sectors. It can be used as a desiccant — a material that absorbs moisture from an environment — and is available in different form factors, like a powder, paste, or finished surface.

What does this mean for aerospace activity? Let’s look at applications for this material and how it could empower the next innovations in space.

Re-entry vehicles

According to NASA, typical low Earth orbit re-entry speeds approach 17,500mph. CoralPor serves as a thermal protection system for re-entry vehicles and is a critical factor in bringing vehicles back safely.

When engineers design re-entry vehicles, they need to consider which materials give them the most control in hitting the re-entry corridor. With too much drag, the vehicle will undershoot its target; with too little, it will overshoot. As they build these vehicles with precision in mind, engineers need a coating that can withstand the conditions and speed of attempting to enter the Earth’s atmosphere, while also being pliable enough to co-exist with the materials that offer the most control of the vehicle.

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CoralPor has a low thermal expansion coefficient as it is made of 95%-to-97% silica; It’s well suited to withstand the extreme heat generated at the nose of the vehicle. The material is available in a variety of pore sizes, which can help tailor the application to specific speeds.

NASA’s Orion capsule recently survived the hottest and fastest re-entry ever performed by a spacecraft. While the vehicle was unmanned this time around, Orion is scheduled to carry astronauts for a mission in 2024, underscoring the importance of a safe landing.

Hypersonics

Broader than just re-entry space applications, hypersonic vehicles have become a priority for military use. The Department of Defense has outlined this technology as a focus for missile defense developments. With more resources going toward this initiative, there is a need for materials that enable hypersonics to travel at more than five times the speed of sound.

Constructing hypersonics creates a challenge because friction with the atmosphere generates surface temperatures up to 5,000°F at the nose of the vehicle. Since the remaining areas of the vehicle don’t get nearly as hot, there is special attention paid to the nose so the vehicle can travel without damage. Very few materials can withstand those temperatures, so engineers typically use carbon-carbon, a very expensive material with limited manufacturing capacity in the U.S.

The DOD is interested in either a revival of carbon-carbon manufacturing or alternatives that can serve the same purpose. CoralPor can cover a lot of the vehicle’s acreage, is readily available, and is a far more cost-efficient alternative. The material has filled a void for other applications where nanoporous glass was the tool of choice and the sole manufacturer discontinued the product. Chemists and chromatography practitioners have found CoralPor to provide a solution, and the same is now true with hypersonics.

R&D capabilities

CoralPor was developed by SCHOTT’s research and development team in Duryea, Pennsylvania, as a lab application, and its uses kept growing. It has been tweaked for customized solutions and can be further adjusted for even more unique applications.

The best R&D projects prioritize versatility, which is the core of CoralPor’s origin story. Over its 130-year-plus existence, SCHOTT has often transitioned from innovation within the R&D organization to production in business units in a cost-efficient manner. An intricate process goes into creating CoralPor, maximizing advantages that make its applications nearly universal.

The material’s interconnected coral-like structure is formed when borosilicate glass is melted, rapidly quenched, and phase separated. The process triggers detachment of the individual glass components, creating a sodium borate phase and silicate phase. Finishing the process, specialized chemicals dissolve the sodium borate phase to yield an interconnected microstructure with open porosity.

As more trends are developed in space, and new needs arise, partners will be needed to ensure the right materials are used to enable a successful mission and production processes can be tweaked to arrive at the best solution. That kind of innovation is in SCHOTT’s DNA, and the company continues to develop new materials that provide value to design engineers looking to advance aerospace technology.

With new challenges facing the aerospace industry, organizations will look to find efficiencies. One way to do that is to identify versatile materials that can be manufactured domestically to reduce supply chain interruptions and adjusted to satisfy a variety of considerations in aerospace travel. Whatever the next trend in aerospace is, CoralPor may be the material needed to ensure the mission is a success.

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