This is the Marc 80 solid propellant rocket motor that is responsible for launching the Stinger portable (shoulder held) air defense system that has been in operation in the United States and many other countries since the early 1980s.
Also visible in this cutaway is the simulated propellant, called "Arcite". The Atlantic Research Corporation, a long-established maker of small-scale solid propellant rocket motors for civilian and military applications, manufactured the Marc 80 shown here.
Transferred to NASM from the Atlantic Research Corporation.
This object is on display in Rockets & Missiles at the Steven F. Udvar-Hazy Center in Chantilly, VA.