6 ms·

It's probably the engine bells, since they are known to contain copper, and copper burns green. Source: https://mobile.twitter.com/elonmusk/status/117738714111

• chasd00 6y ago
  copper gets used because it conducts heat very well and so assists in cooling. In one of the first test stand videos of a raptor run you can see a little bit of green and I think Musk even tweeted it was running "a little engine rich". the first time I watched a night flight of a falcon9 there was a green glow right at ignition which caused me to hold my breath but that was the hypergolic ignition fluids which also burn green. Raptor uses a torch ignition so any green from a Raptor is very bad news.