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PICA-X is a SpaceX proprietary variant on the NASA Ames developed PICA (Phenolic Impregnated Carbon Ablator) heat shield material. NASA quotes decades of rigorous research, testing and development that went into it, and on this photograph we see PICA tested with the use of NASA Ames' arcjet:

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   NASA Ames' arcjets were integral to the testing of the PICA thermal protection material. Credit: NASA Ames

SpaceX additionally worked on it with Dan Rasky, one of the original developers of the PICA material, to develop the new PICA-X material. But how does PICA-X differ from its predecessor PICA, which, while it has some fantastic thermal properties, is really light and an improvement over FiberForm®, is also structurally rather weak (PDF) and can still grow fractures in the matrix when subjected to thermal and mechanical loads during both launch and atmospheric entry?

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   Matrix cracking in charred PICA samples. Source: Fracture in Phenolic Impregnated Carbon Ablator, NASA Ames Moffett Field, 2011

To what degree has SpaceX managed to improve on PICA material characteristics with their proprietary PICA-X? Has it been tested for typical stress loads aboard Falcon 9 to LEO and reentry, and what were the results in terms of both comparing PICA and PICA-X and potential reuse cycle?

I realize that I'm asking about proprietary technology that not much might be known about yet, but I'm looking for stress test results of a material that will support human spaceflight in the near future and surely SpaceX will have much reassuring to do that their technology is safe and performs as expected also in real life. So I expect at least some research of PICA-X eventually also published. Please no speculations, I'm perfectly happy to wait for answers that can be supported by facts and references, once they become available.

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    $\begingroup$ Please note that PICA-X was actually one out of three variants selected by SpaceX during tests at Ames. $\endgroup$ – Deer Hunter Mar 4 '15 at 3:35
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    $\begingroup$ @Val There is no advertisement in this question. It is perfectly appropriate to give a reasonable amount of background to make the question clear. This seems to give the right amount of detail. If you wish to continue this discussion, please bring it to the chatroom. $\endgroup$ – PearsonArtPhoto Jun 25 '15 at 12:19
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SpaceX made improvements in several areas:

  1. Production cost. PICA-X is 10 times less expensive than the original.
  2. Resilience. As you noted, PICA is structurally weak. Reportedly, PICA-X is better in this regard: it's more resisant to cracking, so it can be manufactured in large tiles (notice the tile size in this image):
    PICA-X

  3. Heat resistance.

  4. SpaceX also wanted to be able to manufacture the material in-house in order not to be dependent on a single supplier.

PICA-X has been tested by NASA before its first use, but the test results haven't been published as of 2015.

Unfortunately, I haven't been able to find detailed studies on PICA-X's performance, cost or composition.

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