vernier engine

vernier engine

[′vər·nē·ər ′en·jən]
(aerospace engineering)
A rocket engine of small thrust used primarily to obtain a fine adjustment in the velocity and trajectory of a rocket vehicle just after the thrust cutoff of the last sustainer engine, and used secondarily to add thrust to a booster or sustainer engine. Also known as vernier rocket.
References in periodicals archive ?
Finally, a trio of equidistantly placed Reaction Motors Division (RMD) Vernier engines slowed several Surveyor spacecraft for lunar soft landings during 1966-1968.
The analysis revealed that Pyongyang had used four Nodong missile engines and four vernier engines for the first stage booster to produce 120-ton thrust.
Later that morning technicians explained that one of the rocket's tiny vernier engines had malfunctioned.