Definition of vernier engine in English:

vernier engine

noun

  • another term for thruster
    • ‘The vehicle is slightly unstable on the way up, but we have plenty of control authority from the vernier engines.’
    • ‘Small, single flap skirt armor connected directly to the upper legs, vernier engines stored inside being the only reason the armor had been placed there.’
    • ‘Flight control was achieved by vernier engines located on the strapon boosters and the core sustainer.’

Origin

1950s: named after P. Vernier (see vernier).