This is the recent hotfire test of Astra's most powerful Rocket 4 first stage engine.The quick green flash comes from a special compound called triethylborane (TEB). It's pyrophoric - meaning it spontaneously ignites the moment it touches air. That super-hot green flame then lights the main propellants: kerosene and liquid oxygen.Once ignited, the engine unleashes a roaring orange plume and huge clouds of smoke. These ground tests prove the engine is ready for flight - checking thrust, stability

Jet.Nerd on Instagram: "🔥 SR-71 Blackbird Fuel — The Jet Fuel That Couldn’t Burn Easily! 🛩️💀 The SR-71 didn’t use normal jet fuel. It ran on JP-7, a super-stable, heat-resistant fuel created just for this beast. Here’s why 👇 ⚙️ At Mach 3+ speeds, the Blackbird’s skin reached over 600°C (1,100°F) — regular fuel would’ve boiled or exploded. 🧊 JP-7 was so stable, you could drop a lit match in it… and nothing would happen! 🔥 To ignite it, the SR-71 needed a chemical called triethylborane (TEB)