Benoît Laplante 🛩🚀🛰️ 🇨🇦

Why the blue exhaust? No, it does not mean the combustion products are hotter. And no, this is not branding by @blueorigin. Gas-phase flames are not blackbody emitters unless they are producing soot, so color does not indicate temperature. The particular shade of blue you see has more to do with the specific spectral bands of the vibrational modes of the molecules produced. Carbogen (CH∗) emits radiation at 431 nm, in the indigo part of the spectrum. C-C vibrational modes emit throughout the blue-green region of the spectrum (Swan bands). We are likely seeing a mixture of these. The solid rocket exhaust *is* particulate exhaust, and is a condensed-phase black body emitter. Here you *can* correlate color with temperature. For the LOX-kerosene boosters we are used to (Merlin, RD-180), you see a mixture of spectral emission (blue lines) and soot (orange condensed phase blackbody). For H2-O2 (SSME, BE-3) you see essentially nothing.

Best footage I've seen of #shotdown. Clearly a fragmentation missile intercepting region between balloon and payload.