Following the failed launch of the Geosynchronous Satellite GSLV-F10/Earth Observation Satellites (EOS)-03 in 2021, a high-ranking panel was assembled to scrutinize the incident. The panel has recommended strategies to enhance the Cryogenic Upper Stage (CUS), the failure of which led to the unsuccessful mission. Consequently, improvements to the GSLV’s CUS are planned to be ready by the second half of this year.
Understanding the Geosynchronous Satellite Launch Vehicle (GSLV)
The Indian Space Research Organisation (ISRO) exclusively designed, developed, and operates the GSLV. This space launch vehicle serves to transport satellites and other space objects into geosynchronous transfer orbits. Specifically designed for communications satellites, these are launched in the same direction as Earth’s rotation, allowing them to appear fixed in one position in the sky. With its capacity to carry heavier payloads than the Polar Satellite Launch Vehicle (PSLV), GSLV is a three-stage launcher with strap-on motors.
The Cryogenic Upper Stage
The GSLV follows a solid fuel initial phase, succeeded by a liquid fuel stage. The crucial third stage, known as the Cryogenic Upper Stage (CUS), failed during the GSLV-F10 mission. The CUS is a technically complex system that uses propellants at extremely low temperatures, thereby creating thermal and structural challenges.
Exploring Earth Observation Satellites
Equipped with remote-sensing technology, these satellites facilitate the collection of information regarding Earth’s physical, chemical, and biological systems. Many of these satellites operate on sun-synchronous orbits. ISRO’s repertoire includes several earth observation satellites like RESOURCESAT- 2, 2A, CARTOSAT-1, 2, 2A, 2B, RISAT-1 and 2, OCEANSAT-2, and many others.
Types of Launch Vehicles Used by ISRO
ISRO used a variety of launch vehicles, starting off with the Satellite Launch Vehicle (SLV), succeeded by the Augmented Satellite Launch Vehicle or ASLV. Each of these could carry small satellites of up to 150kg into lower earth orbits. However, they were phased out in the early 1990s and replaced by the PSLV. Nowadays, ISRO primarily uses the PSLV and the GSLV, both having different variants.
The Small Satellite Launch Vehicle (SSLV) is designed specifically for the global demand in launching small and micro-satellites. The indigenously developed CUS forms the third stage of GSLV Mk II, and Mk-III versions.
The Future of Rockets: Reusability
In an aim to reduce costs, energy consumption, and space debris, the future of rocket technology lies in reusability. Only a small part of the rocket would be destroyed during the mission while the majority would re-enter Earth’s atmosphere to be used in subsequent missions. While fully-reusable rockets are yet to be developed, partially-reusable launch vehicles are currently in operation. ISRO has developed its reusable rocket, the Reusable Launch Vehicle Technology Demonstrator (RLV-TD), which had a successful test flight in 2016.
