The second stage propulsion system for N-launch vehicle

The pressure-fed second stage propulsion system for N-launch vehicle provides 53,348 N (5440 kg) thrust for about 250 sec at an Isp of 290.2 sec. Aluminum tanks, integral with vehicle structure, carry a minimum of 4.7 ton propellant combination of N₂O₄ and Aerozine 50. The gimbaled engine consists of a regenerative cooled chamber, ablative nozzle spacer, and a radiation cooled nozzle extension with an exit area ratio of 26. Utmost utilization of domestically available technology and facilities underlay the design concept. Development of the propulsion system took 5 years with the first flight occurring in 1975. Five consecutive flight successes up to 1979 have demonstrated the reliability and performance of the system.Improved N vehicle, designated as N-II, will succeed the N vehicle. New second stage propulsion system for N-II delivers 43,816 N (4468 kg) thrust at an Isp of 314.1 sec and has restart-capability.