This is a full-scale mockup of an extended BE-3-B solid propellant rocket motor of the type used to inject the Advanced Vela Nuclear Detection Satellites into orbit. Hercules, Inc. developed the motor in 1960, originally as a retro rocket for the Ranger family of lunar probes. It was also used as the fourth stage of the Athena sounding rocket and as the fourth stage of the Sparta missile. The BE-3-B produced 7,700 pounds of thrust for 7.9 seconds and used a double-base propellant. Hercules donated the motor to the Smithsonian in 1968.