Indian Space Research Organisation (ISRO) announced the successful development of a lightweight Carbon-Carbon (C-C) nozzle for rocket engines, heralding a new era in rocket engine technology. This significant innovation, accomplished by the Vikram Sarabhai Space Centre (VSSC), is poised to elevate the performance of rocket engines by enhancing crucial parameters such as thrust levels, specific impulse, and thrust-to-weight ratios, consequently boosting the payload capacity of launch vehicles.
Leveraging advanced materials like Carbon-Carbon (C-C) Composites, the VSSC has engineered a divergent nozzle with exceptional properties, as stated by ISRO. The process involved in its creation includes carbonisation of green composites, chemical vapour infiltration, and high-temperature treatment. The resulting nozzle exhibits low density, high specific strength, and excellent stiffness, retaining its mechanical properties even at elevated temperatures.
A standout feature of the C-C nozzle is its special anti-oxidation coating of silicon carbide, extending its operational limits in oxidising environments. This breakthrough not only reduces thermally induced stresses but also enhances corrosion resistance, enabling extended operational temperature limits in challenging environments.
The potential impact of this development is particularly significant for ISRO’s workhorse launcher, the Polar Satellite Launch Vehicle (PSLV). Currently, the fourth stage of the PSLV, known as PS4, employs twin engines with nozzles made from Columbium alloy. However, by substituting these metallic divergent nozzles with C-C counterparts, ISRO anticipates a remarkable mass reduction of approximately 67%.
This substitution is projected to increase the payload capability of the PSLV by 15kg, a substantial enhancement for upcoming space missions. The successful testing of the C-C nozzle divergent represents a major milestone for ISRO.
ISRO elaborated on the testing process, stating, ‘On March 19, a 60-second hot test was conducted at the High-Altitude Test (HAT) facility in ISRO Propulsion Complex (IPRC), Mahendragiri, confirming the system’s performance and hardware integrity. Subsequent tests, including a 200-second hot test on April 2, 2024, further validated the nozzle’s capabilities, with temperatures reaching 1216K, matching predictions.’
This achievement was made possible through a collaborative effort involving the Liquid Propulsion Systems Centre (LPSC) at Valiamala, which designed and configured the test, and IPRC, Mahendragiri, which conducted the instrumentation and execution of the tests at their HAT facility.
