Amateur rocketry

Amateur rocketry, sometimes known as experimental rocketry or amateur experimental rocketry, is a hobby in which participants experiment with fuels and make their own rocket motors, launching a wide variety of types and sizes of rockets. Amateur rocketeers have been responsible for significant research into hybrid rocket motors, and have built and flown a variety of solid, liquid, and hybrid propellant motors.

To qualify as "amateur rocket", it's generally accepted a few criteria must be met:

1. The rockets must be designed by amateurs, rather than using professionals in the aerospace field or copying existing designs.
2. The rockets must also be built by amateurs, relying on their own resources, knowledge, and craftsmanship.
3. Without substantive assistance from organizations such as NASA, the U.S. Military, or professional aerospace companies.

These enthusiasts, though not part of a formal industry, often achieve remarkable success and contribute to advancements in rocketry through independent experimentation and innovation.