This rare footage shows NASA testing the X-43A, an experimental hypersonic aircraft built to explore extreme-speed flight. Because scramjet engines cannot start from rest, the vehicle was carried under a B-52, boosted to hypersonic speed by a rocket, and only then ignited its own engine. | SpaceEve

Watch | ISRO successfully test-fired Scramjet Rocket Engine, showcasing an advanced air-breathing device. Here is how a scramjet rocket engine works. | Mint