Rocket Propulsion Systems: Chemical, Nuclear, and Thermonuclear Engines in the Context of Kazakhstan’s Aerospace Future.

This research presents a comparative assessment of three major propulsion paradigms—chemical (RS-25), nuclear-thermal (NTR), and thermonuclear (PFRC)—to determine their relative feasibility for future deep-space missions and for emerging space programs such as Kazakhstan’s. A harmonized framework was developed to normalize thrust, specific impulse, system mass, and operating temperature under consistent assumptions, enabling direct cross-class comparison. Using data from NASA, DARPA, and NIAC sources, the study translates engine-level metrics into architecture-level outcomes including payload fraction, transfer duration, and readiness level. Results show that chemical engines, although fully mature (TRL 9), are constrained by the limits of combustion efficiency. Nuclear-thermal systems roughly double the specific impulse while maintaining practical thrust levels, making them the most realistic near-term option for Mars and cislunar missions. Fusion propulsion promises an order-of-magnitude leap in performance, yet its technology remains in an early conceptual stage (TRL 2–3). Overall, nuclear-thermal propulsion emerges as the most balanced solution—combining strong performance, proven principles, and strategic compatibility for nations with nuclear expertise—while fusion stands as a long-term goal for future exploration.