Heat shielding for spacecraft

Since the invention of Aeronautics, there has always been a push to explore further boundaries. Flying at supersonic speed as well as reaching the outer space are some of the humankind dreams that have led to the development of many innovative technologies.
Protecting a vehicle from the aggressive environments and conditions encountered during operations is particularly key. Thermal Protection Systems (TPS) are designed to play the critical role of being a shield for what is underneath them. Hypersonic vehicles and Spacecraft, during their atmospheric re-entry, are common applications where TPS are required to manage the intense heat encountered.
Low density materials in TPS are particularly attractive because of the combination of effectiveness at heat management and optimized fuel consumption. Flexible materials can be beneficial in the design of a TPS as it allows less inherent stress and helps reduce mechanical issues linked to differing thermal expansion (CTE) of rigid materials in a TPS.
Quartzel® fibers in the form of non-woven substrates (Veil, Felt, and Needle Punched Felt) meet these desired characteristics of silica SiO2 thermal resistance, low density substrate, and flexibility. Quartzel® yarns and rovings can also be woven to provide a variety of 2D woven fabrics, with common areal weight of up to 700g/m², as well as 3D woven fabrics dedicated to special programs.

 Quartzel® chopped fibers, woven and non-woven products in TPS applications are often combined with a high temperature polymer or ceramic matrix.  As these materials function together as a composite within the TPS, they can be designed to be sacrificial ablative layers providing cooling for the vehicle by moving the heat flux of the outer layer away from the vehicle through the gasses produced during the pyrolysis reaction of the ablative material. Indeed, the transformation of solids into gasses without oxygen, also called pyrolysis, is a chemical transformation which inherently absorbs heat during the material transformation in gas.
Quartzel products have been used over years in many Space & Defense programs and continue to be a material of choice in this domain. The latest example has been successfully qualified by Bally Ribbon Mills (BRM, Los Angeles, Calif., U.S.) in a form of a 3D woven substrate infused with organic resin. Once machined, the composite is used as part of the thermal shield of the Orion crew capsule which aims at protecting it from the heat generated during atmospheric re-entry. Orion spacecraft will carry astronauts to the Moon, and later to Mars, and return them safely back to Earth with the help of BRM technology. Stay tuned as the first test flight of Artemis mission containing an Orion Capsule is scheduled before end of 2022.
*Credits pictures: Bally Ribbon Mills

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