Engineers building NASA’s Orion are making manufacturing improvements for the spacecraft ahead of its missions to deep space destinations near the moon and on the journey to Mars.
The Orion capsule’s heat shied successfully survived its test flight last year reaching temperatures of about 4,000 degrees Fahrenheit and speeds approximately 80 percent of what it will endure when it comes back from missions near the moon, all while keeping the temperature inside the crew module in the mid–70s. Post-flight examinations of the heat shield confirmed it performed well within expected tolerances.
The heat shield was composed of a titanium skeleton and carbon fibre skin that gave the crew module its circular shape on the bottom and provided structural support, on top of which a fibreglass-phenolic honeycomb structure was placed. The honeycomb structure had 320,000 tiny cells that were individually filled by hand with an ablative material called Avcoat designed to wear away as Orion returned to Earth through the atmosphere. During the process, each individual cell was filled by hand as part of a serial process, cured in a large oven, X-rayed and then robotically machined to meet precise thickness requirements.
However, during the manufacture of the heat shield for Orion’s flight test, engineers determined that the strength of the Avcoat/honeycomb structure was below expectations. While analysis showed, and the flight proved that the heat shield would work for the test, the EM–1 Orion will experience colder temperatures in space and hotter temperatures upon reentry, requiring a stronger heat shield.
Through lessons and data obtained from building and flying the heat shield, the team was able to make a design update for the Avcoat block design that will meet the EM–1 strength requirements. It is also expected to provide a cost savings and shorten the current heat shield manufacturing timeline by about two months. Engineers have now folded the update into the design review that will lock down the design for the next version.