Well We Know Where Were Goin, But We Dont Know Where Weve Been*

So, it appears that we have yet another aspect of NASA's Orion moon program, the heat shield, where the original material, Phenolic Impregnated Carbon Ablator (PICA) has been replaced with an updated version of Avcoat, which was used in the original Apollo capsule.

The PICA heat shield was delivered late, and looked to be overkill for what should be the primary mission of the spacecraft, low earth orbit, with a focus on servicing the space station.

This is a reversal from the decision made in 2006 by both NASA and Lockheed-Martin, the prime contractor, to go with PICA, and that should have been the end of the story, only the preliminary design review (PDR) also scheduled for that year has still not been held, and Avcoat showed lighter weight than the original, along with significant reductions in the toxic substances used in its manufacture.

Confused? So is NASA, so it seems.

^*The first two lines of the Talking Heads song Road to Nowhere. It's a metaphor for NASA.