The amount of work required to simplify the Raptor engine, internalize secondary flow paths and add regenerative cooling for exposed components was staggering.
As a result Raptor 3 doesn’t require any heat shield, eliminating heat shield mass & complexity, as well as the fire suppression system.
It is also lighter, has more thrust and has higher efficiency than Raptor 2.
Truly, a work of art.
Shutdown of a Raptor vacuum engine in slow motion. The engine’s nozzle is sized for use by Starship in the Earth’s upper atmosphere and outer space, so operation at sea level and low chamber pressures results in flow separation creating visible rings in the exhaust