Cryogenic Upper Stage Project for GSLV crossed a significant milestone yesterday (September 14, 2002) with the successful ground test firing of the indigenous cryogenic engine for a duration of 1000 seconds. The test was carried out at the Liquid Propulsion Systems Centre (LPSC) test complex at Mahendragiri in Tamil Nadu. The performance of the test was normal.

The cryogenic engine, using a combination liquid hydrogen and liquid oxygen, is required to be operated in GSLV flight for about 700 seconds. Yesterday’s test, which is of longest duration conducted so far, is also unique in increasing the performance of the thrust for part of the test duration by pre-programmed sequencing for the first time. The test is part of the series of a number of such evaluation tests to characterize the different performance parameters under various operating conditions.

This turbo-pump fed, regeneratively cooled engine produces a nominal thrust of 7.0 tonne in vacuum. The engine has been tested in the facilities specifically established to handle liquid hydrogen and liquid oxygen along with the associated control, instrumentation, data acquisition system and safety devices.

Cryogenic propulsion has been selected for the upper third stage of GSLV (Geosynchronous Satellite Launch Vehicle) in view of its higher efficiency compared to solid and liquid propulsion systems. However cryogenic technology is quite complex and is the preserve of only five other nations. The behavior of materials at cryogenic temperatures of less than 250 degree below zero, the turbo pump operating at very high speeds of the order of 40,000 rpm, the elaborate chilling process for preparing the ground and on-board systems, the interplay of critical engine parameters and a host of technical aspects make the development quite challenging.

LPSC, the lead centre for the Liquid Propulsion Systems is responsible for the realization of the cryogenic engine and associated test facilities with the support of Vikram Sarabhai Space Centre (VSSC) at Thiruvananthapuram and Satish Dhawan Space Center, SHAR. Indian Industries have significantly contributed in the realization of the cryogenic engine.

While yesterday’s test validates the design adequacy of the engine, further demonstration tests are planned at engine and stage level during this year.