Which statement is always true concerning a hybrid rocket motor?

Which statement is always true concerning a hybrid rocket motor?

• A. The fuel component is composed of either paper or plastic
• B. The fuel is in a different physical state (solid, liquid, or gaseous) than the oxidizer
• C. The oxidizer component is nitrous oxide
• D. Both 'A' and 'C' above

Answer: (B)

Hybrid rocket motors rely on two propellants in different physical states: a solid fuel grain and a separate oxidizer, typically stored as a liquid. This separation is what makes hybrids controllable—fuel stays in a solid form for the burning surface, while the liquid oxidizer is fed into the chamber to sustain the combustion. Because the fuel can be a variety of solid materials (not limited to paper or plastic) and oxidizers can differ (nitrous oxide is common but not universal), the only statement that holds true in all hybrid designs is that the fuel and oxidizer are in different physical states. This fundamental arrangement enables throttling and shut-off by regulating the oxidizer flow, which is not guaranteed by the other options.

Hybrid rocket motors rely on two propellants in different physical states: a solid fuel grain and a separate oxidizer, typically stored as a liquid. This separation is what makes hybrids controllable—fuel stays in a solid form for the burning surface, while the liquid oxidizer is fed into the chamber to sustain the combustion. Because the fuel can be a variety of solid materials (not limited to paper or plastic) and oxidizers can differ (nitrous oxide is common but not universal), the only statement that holds true in all hybrid designs is that the fuel and oxidizer are in different physical states. This fundamental arrangement enables throttling and shut-off by regulating the oxidizer flow, which is not guaranteed by the other options.