This is an unflown Uni-Jet D1 model rocket motor manufactured by Uni-Jet. The "D1" signifies that the power of the motor is in the fourth highest class (out of of seven) established by the National Association of Rocketry. It is made of pasteboard and contains non-explosive propellant. A motor is used only once to power a model rocket.
G. Harry Stine, a pioneer in the field of flying rocket models, donated the artifact to NASM in 1973.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.