Orion Heat Shield Takes Shape

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NASA PR — A relationship that began more than 50 years ago between NASA and Textron Defense Systems continues today through the Orion Program, where the two are working together on a familiar project: a heat shield that will allow astronauts to safely return from deep-space missions.

In the 1950s, Textron pioneered a lightweight ablative material with a specific formula of silica fibers with an epoxy-novalic resin developed just for the Apollo crew capsule. Avcoat, as the material is called, is designed to protect the structure from extreme temperatures by burning away as it heats up, rather than transferring the heat on to the rest of the capsule. It saw Apollo astronauts through 11 safe landings, and was chosen to repeat the job now that NASA is planning to send Orion and its future crews to destinations never before visited by humans.

Textron technicians apply the Avcoat material by “gunning” the material into each of the 330,000 individual cells of the honeycomb structure. (Credit: NASA)

Textron technicians apply the Avcoat material by “gunning” the material into each of the 330,000 individual cells of the honeycomb structure. (Credit: NASA)

On its first mission next year, the Orion spacecraft will travel 3,600 miles into orbit and return to Earth at speeds up to 20,000 miles per hour – faster than the space shuttles or any other spacecraft in the past 40 years. And because high velocity always translates to higher temperatures during spacecraft re-entry, Orion must endure temperatures of up to 4,000 degrees Fahrenheit. In addition, future missions could take Orion and its crew to asteroids and Mars, which is why Orion will need the biggest, most advanced heat shield ever built.

A team of NASA engineers spent more than three years studying eight different candidate materials for Orion’s heat shield, before narrowing the field down to two final candidates, Avcoat and Phenolic Impregnated Carbon Ablator, or PICA, both of which have proven successful in previous space missions. Avcoat, which was last used in specific areas of the space shuttle orbiter in its earliest flights, was put back into production for the study and eventually chosen as the right candidate.

“It’s a great source of pride for the company to have such a long standing history in being involved in space exploration and to be able to provide this legacy material,” said Jeff Picard, Textron Defense System’s vice president of program execution. “Avcoat is the only man-rated ablative material that exists today. It’s a tremendous honor for us to help the United States to further the country’s exploration of space by providing our thermal protection material.”

A team of technicians at Textron Defense Systems apply Avcoat ablative material to the composite honeycomb structure attached to the Orion heat shield carrier structure. The ablative material is designed to protect the spacecraft from extreme temperatures during re-entry. (Credit:  NASA)

A team of technicians at Textron Defense Systems apply Avcoat ablative material to the composite honeycomb structure attached to the Orion heat shield carrier structure. The ablative material is designed to protect the spacecraft from extreme temperatures during re-entry. (Credit: NASA)

The skeleton and skin of Orion’s heat shield was assembled at Lockheed Martin’s Waterton Facility near Denver then shipped to Textron, with whom Lockheed Martin has a subcontract. Since its arrival, technicians have installed a fiberglass-phenolic honeycomb structure to the surface and begun carefully filling each of the 330,000 individual cells of the honeycomb with the Avcoat through a process Textron engineers refer to as gunning. Each cell is then examined under X-ray and machined (a sanding-like process) down to the exact specifications called for in Orion’s design.

“As a batching process engineer, I monitor the process,” Michelle Pelersi, material engineer for Textron Defense Systems, said. “We take all of the raw materials, mix them and then load the Avcoat material into cartridges to get it ready for gunning. Our technicians gun the material in the shield, and I make sure every batch meets our requirements and ensure the gunning process is performed successfully.”

The long-standing partnership between Textron and NASA is an example of how America is a nation made up of explorers.

“Working with NASA over the years and being a part of space exploration, has been a rewarding experience for everyone associated with Textron,” Picard said. “It’s very inspirational to partner with an agency such as NASA, and to be able to contribute something advances humanity’s understanding of the solar system. Our entire project team can’t wait to see Orion take us farther than we’ve ever been before.”