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SpaceNut

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From: New Hampshire

Registered: 2004-07-22

Posts: 28,946

Re: Constellation (Cx)

The testing of Orion was to give us back to abilities of Apollo and part of that was the heatshield. We supossedly had lost the ability to make them as the formular was lost but the Avcoat is what was settled on.

Engineers finding lessons in nearly flawless orion test flight

Avcoat insulation manually applied to 330,000 individual cells on the heat shield’s fiberglass-phenolic honeycomb structure was supposed to ablate away during the Orion spacecraft’s re-entry, protecting the underlying structure from searing temperatures.

“Every single one of those cells is filled with the Avcoat material with a putty gun, then it’s cured, formed and rounded,” Hawes said. “When you look at that honeycomb structure, you imagine that over this 16-foot diameter heat shield. Every single one of those gets filled with a caulk gun manually by a technician. That’s one of our bigger concerns with the heat shield — just the long term manufacturing and to make it less touch intensive.”

The Orion heat shield’s titanium skeleton and carbon fiber skin was fabricated by Lockheed Martin in Colorado. The skeleton was shipped to Textron Defense Systems in Massachusetts for installation of the honeycomb structure and filling of the Avcoat cells.

NASA and Lockheed Martin may change the heat shield design for future Orion missions, using the same material but a different manufacturing method.

Instead of attaching the heat shield to the capsule in one piece — called a “monolithic” design — engineers are evaluating a switch to a “block” approach using several pieces.

“We knew that there some areas of the curvature that looked like they were lower strength than we had expected,” Hawes said. “All of those areas survived the flight extremely well … That gives us some confidence in some of the shortcomings of what we thought about the monolithic structure. We’re still worried overall over the manufacturability of the monolithic shape just because it’s very hand touch labor intensive.”

The heat shield from the EFT-1 mission has been removed from the capsule and prepared for shipment to NASA’s Marshall Space Flight Center in Alabama where the leftover Avcoat material will be scraped off. The titanium base of the heat shield will then go to NASA’s Langley Research Center in Virginia for water impact testing, Hawes said.

Hawes said Lockheed Martin and NASA are slated to discuss the future heat shield design in a few weeks.