Mass. Gen. Laws ch. 148 § 9A
The board shall make rules and regulations for the keeping, storage, manufacture, sale and use of model rocket engines and for the launching, operation and flying of model rockets in accordance with nationally recognized standards for model rocketry as promulgated by the National Fire Protection Association. As used in this section, "model rocket engine" shall mean a solid propellant rocket engine produced by a commercial manufacturer in which all chemical ingredients of a combustible nature are preloaded and ready for use, and "model rocket" shall mean an aero model that ascends into the air without use of aerodynamic lifting forces against gravity that is propelled by means of a model rocket engine that includes a device for returning it to the ground in a condition to fly again and whose structural parts are made of nonmetallic material.
Mass. Gen. Laws ch. 148, § 9A