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Quote:

Originally Posted by frognbuff

Nothing in those photos implied a white core. White-painted composite sections, but not white on the actual core. The cartoon was white, but lots of cartoon depictions of SLS have been white. I'm still betting against it. Painted SOFI (spray-on foam insulation) is just heavy and expensive. Reference the Shuttle Program with one painted ET (or was it two?). The only engineering reason I can think of for doing it would be to provide a coating better suited to mitigating electrostatic discharge. So, I suppose there's a chance!

For what it's worth, SOFI is pale yellow when first applied. It gradually turns more and more orange - almost brown - when exposed to UV light. Bond-on foam insulation (BOFI) maintains a more yellow appearance. Looking at the Green Run booster, I think there's quite a bit of BOFI on there too.

It was two ET's that were white... first two flights. After that paint was deleted along with the about 800 lbs it added to the ET. (LOT of square footage means a LOT of paint, plus application expenses).

The only real benefit to the paint is it might help resist UV damage to the foam if the components are outside for a long period of time. BUT realistically it shouldn't be out there THAT long... most of us who've ever used "spray foam in a can" probably have some poking out of cracks in the siding or shed or around exposed plumbing outside that has been there for YEARS and while weathered is still acceptable SO... Paint sure wouldn't ward off the woodpeckers that damaged the foam on one of the shuttle missions that sat on the pad a long time... If the foam is applied correctly water intrusion isn't an issue, and if it's not, paint isn't going to prevent that either...

That's why it was ultimately deleted from the shuttle, and I don't see ANYTHING beyond flashy artwork that leads me to believe they'll paint the tanks on SLS. IF the SLS ever even flies.

Later! OL J R