Heat Shield

Arguably the most important piece of equipment required for the safe return of astronauts from orbit to Earth was the aft heat shield. Attached to the bottom of the Command Module and made of an ablative material, the heat shield protected the craft from temperatures often exceeding 5,000 degrees Fahrenheit. The ablative material, called AVCOAT by NASA, was developed by Avco.

Guidance Systems and Navigation
J2 Rocket Engine