FIRSTstage
First stage is the initial segment of a multi-stage system, occupying the lowest position in a vehicle or process. It is designed to perform early tasks and to provide the necessary initial energy or momentum, after which subsequent stages take over.
In rocketry, the first stage is the launch propulsion unit that supplies most thrust during ascent. It
In other contexts, the term denotes the initial phase of a process. Examples include manufacturing pipelines
Notable uses include Saturn V’s first stage, the S-IC, which relied on multiple large engines to provide
See also: stage, multistage rocket, stage separation, booster.