AVCOAT

AVCOAT 5026-39 is a NASA code for two versions of a specific ablative heat shield material originally created by Avco for the Apollo program.

The Avcoat used on the two types of Orion shield was reformulated to meet environmental legislation that was enacted after the end of Apollo.

NASA confirmed that this is made of silica fibers with an epoxy novolac resin filled in a fiberglass-phenolic manufactured directly onto the heat shield.

To protect the Crew Module during Earth re-entry, the dish shaped AVCOAT heat shield ablator system was selected.

John Kowal, Orion's thermal protections systems manager at Johnson Space Center, discussed the biggest challenge with AVCOAT has been reviving the technology for manufacturing with similar performance as demonstrated in the Apollo Missions.

The heat shield was designed and manufactured similarly to the Apollo version as a monolithic fiberglass honeycomb which was then filled with the AVCOAT.

Each cell was individually filled with AVCOAT one at a time by a technician with a pressure gun, with the process taking more than six months for the shield.

This heat shield is covered in titanium truss and a composite substitute with an addition skin made of carbon fiber layers.