This is the attitude control system for the Titan 3E launch vehicle. The system consisted of three SE-9 rocket engines to provide attitude control in three axis. Each engine produced from 45 pounds of thrust and used storable, hypergolic, or self-igniting, propellants that made it simple and reliable. The Titan 3E was a modified U.S. Air Force Titan missile used to launch deep space probes or satellites into geosynchronous orbits. Most notably, the Titan III-E launched two Viking spacecraft to Mars in 1975. These engines were transferred to the Smithsonian in 1970 from the U.S. Air Force.