The same stuff used to paint caves will now orbit the Sun


Bone black. Also known as ivory black. It’s still used as a pigment in artists’ pigments. It’s a nice, soft black.

The material Enbio will apply to the outermost titanium sheet of Solar Orbiter’s multi-layered heatshield is called ‘Solar Black’ - a type of black calcium phosphate processed from burnt bone charcoal.

I wonder how processed. I demand the ESA only use natural organic materials on their space probes!

So the most famous jump-cut in cinema history wasn’t entirely allegorical.


Um, they burn it?

/Wouldn’t ‘burnt’ bone charcoal be, y’know, ash?
//Actually, some of the process details are in the linked-to article.

They describe how they bond it to the metal but they don’t say how much Solar Black differs from burnt bone charcoal. You could call plastic a processed form of oil but they have different properties.

I hasten to point out that technically, the cave paintings have been orbiting the sun as well, and for quite a long time at that.


What makes me curious is that (as best as my PhD in Organic Chemistry from Google, with advanced studies at the Wikipedia Institute for Trivia Studies can tell) the various calcium-phosphorus-sometimes-other-stuff compounds that you’d find in bone aren’t particularly black; but the article specifically mentions that outgassing was absolutely unacceptable (because of the sensitivity of the instruments) so they must have done a fair bit of scrubbing of the chaotic mix of oxidized organics that you’d find in bone char to arrive at the spacecraft coating compound; but I don’t know what you would leave in to arrive at something that is both charcoal black in color and calcium phosphate in composition.

Probably just another item on the ‘things I don’t know’ list; but it’s much more puzzling than if they had, say, gone with carbon black, where you’d plausibly assume that they’d scrubbed out everything but the carbon dust and called it a day.

Pigment aside, this surface bonding treatment sounds very interesting indeed. The oxide layers on aluminum are stubborn things, so the idea of getting your choice of surface property baked in is intriguing. I wonder if I could improvise with a sand blaster and a supply of welding gasses in my back yard?

A new request for my will – I want to be turned into spacecraft paint.


The same stuff used to paint caves will now orbit the Sun

of course, it’s poetic because that stuff (and all stuff in our system) originated from the sun.

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