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Atlas Vernier Engine

Atlas Vernier Engine

Display location: History Center

Type: Vernier engine designated LR 101-NA-7 or MA-3 Vernier
Contractor: Rocketdyne Corporation

Atlas vernier engine positionsUsed on Atlas rockets to provide roll control during flight and final velocity and attitude corrections after sustainer cutoff. This model was used on Atlas E and Atlas F series (SM-65). Ignited about 3.5 seconds after booster engines and sustainer were started. Controlled roll, pitch and yaw trim during spacecraft coasting flight. Made precise attitude adjustments, especially to solid fuel rockets, which are difficult to throttle and steer. Helped attain separation between stages and to "settle" liquid propellants which prevented sloshing and frothing. Capable of operating at temperatures between -30 degrees and +130 degrees Fahrenheit.

Position of the two vernier engines on an Atlas is shown at left.