Based on technology first developed during the Apollo era, the new 5m (16ft) diameter heat shield is made of a material called Avcoat. Consisting of an epoxy novolac resin embedded with special additives the ablative shield is bound together by a fiberglass honeycomb matrix. To add an extra layer of protection to the underside of Orion’s crew module the shield is also covered in a thin layer of reflective tape which will melt away during Earth reentry pulling some excess heat from the module’s leading end.
"The biggest challenge with Avcoat has been reviving the technology to manufacture the material such that its performance is similar to what was demonstrated during the Apollo missions," said John Kowal, Orion's thermal protection system manager at Johnson. "Once that had been accomplished, the system evaluations clearly indicated that Avcoat was the preferred system."
While scientists working on the Orion project are confident that Avcoat will be capable of handling the immense heat generated during reentry (temperatures soar to 4,000-degrees Fahrenheit), NASA isn’t taking any chances.
Later this year NASA will launch an Orion system complete with a dummy crew module into low Earth orbit. During that mission the module will reach some 5,800km (3,600mi) above Earth and reenter the Planet’s atmosphere in a simulation meant to test the new heat shield. If all goes to plan, another one of the thousands of systems that will make up the next-gen Orion rocket will be certified for manned space-flight.
Images Courtesy of NASA