Rocket Engine, Vernier, Surveyor Spacecraft

This is the vernier rocket motor for the Surveyor unmanned lunar landing probe, America's first spacecraft to land on the Moon. The vernier engine was small but of critical importance to provide propulsion for trajectory correction maneuvers, attitude and velocity control before and during landing. The vernier had to be reliable and with restart capability.

The propellants were hypergolic (self-igniting), and the vernier produced 30-104 pounds of thrust for 4.8 minutes. The vernier was swivel-mounted for roll control of the spacecraft. The Reaction Motors Division (RMD) of the Thiokol Chemical Corporation developed the vernier, first used operationally on Surveyor 1, which soft-landed on the Moon on June 1, 1966. Five of seven Surveyors launched successfully landed on the Moon up to 1968. Photos and other data gathered greatly contributed to the later Apollo manned lunar program.

This NASA - Jet Propulsion Laboratory transferred this vernier engine to the Smithsonian Institution in 1979.