Posts: 142
From: London England
Registered: Jan 2008

posted 09-22-2015 04:51 AM               

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I'm currently volunteering at the London Science Museum "Cosmonauts" exhibit.

One of the questions I have been repeatedly asked is the composition of the exterior portion of the Vostok/Voskhod heat shields. My understanding is they were an ablative resin, but would be very grateful if anyone might know a more precise answer and if the recipe was similar to that of United States spacecraft of the time.

Posts: 583
From: Louisville CO US
Registered: Aug 2003

posted 09-25-2015 12:27 PM               

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Specifically, the Vostok and Voskhod heat shields are made with "phenol-formaldehyde resin" in a composition similar to Bakelite. If you get a chance to smell the Vostok behind the glass from less than a meter away, it will smell just like burned 1960s cookware handles. At launch, the entire sphere was covered in a thin asbestos blanket impregnated with phenol resin, but no worries here, the remnants of this have long been scraped away. The exposed metal where you see the honeycomb pattern is a foil of Aluminum-Magnesium alloy. The descent sphere’s pressure vessel is also an Aluminum-Magnesium alloy.

The Gemini heatshield was a bit different using a silicone based elastomer. The Apollo and current Orion material, AVCOAT (TM) is actually similar to the Vostok/Voskhod material in that it uses a phenolic-formaldehyde resin, but different in that it is mixed with epoxy.

Posts: 142
From: London England
Registered: Jan 2008

Posts: 1306
From: Staten Island, NY
Registered: Jun 2007