India’s space programme suffered a mild setback when on August 12, 2021 the indigenously built state of the art earth observation satellite EOS-03, launched aboard GSLV Mk II from Satish Dhawan Space Center, Shriharikota, failed to reach its designated height. The EOS-03 was supposed to be placed first in a geosynchronous orbit and later to be shifted to a geostationary orbit which is nearly 36,000 kms (35,786 kms to be precise) above the equator. It was later revealed that while the first two stages of the GSLV Mk II had functioned normally, the upper cryogenic stage had failed to ignite due to some technical anomaly. It was the 14th flight from the GSLV stable (Mk I and Mk II) and the 8th with the indigenously built cryogenic engine. The mission was originally planned for lift off on March 5, 2020 but had to be deferred hours before takeoff due to technical problems.

The Indian Space Research Organization (ISRO) has a long run of successful missions including Chandrayaan-1 and Mangalyaan-1 among several other satellite launches. But not much had happened since the beginning of 2020. Covid-19 pandemic had apparently taken a toll on the activities of ISRO also.  Consequently, ISRO had planned several launches recently in preparation to the proposed launch of Gaganyaan-3 in 2023 which is to be India’s first manned mission, making it only the fourth country in the world after USSR/Russia, USA and China to send a man in space aboard its own spacecraft. Nationals of as many as 41 countries, including 1 from India (Wg Cdr Rakesh Sharma aboard Soviet spaceship Soyuz T-11 in 1984) have otherwise already travelled to space. The list includes 3 other persons of Indian origin (Late Kalpana Chawla, Sunita Williams and Sirisha Bhandla, all American nationals).

It seems the August 12 launch of EOS-03 was in a way supposed to signal a resumption of ISRO’s activities. Its failure, therefore, is a sort of setback to the ISRO plans and it could  possibly delay several upcoming space programs. Before launching Gaganyaan-3, ISRO has planned a couple of test flights, Gaganyaan-1 and Gaganyaan-2, the latter carrying an empty capsule of appropriate weight in which the Indian ‘astronauts’ would ultimately travel, a sort of a dummy flight to see that all parameters function precisely. This might now take time because GSLV is going to be used for all heavy launches and the 3rd stage of the GSLV, the cryogenic upper stage, which provides the final thrust to do the heavy lifting, is where the fault was detected in the abortive EOS-03 flight. ISRO has to ensure that the cryogenic upper stage functions without a glitch. In fact, it has experienced problems with the cryogenic engines earlier also.

The GSLV project was launched in 1990 with the objective of acquiring indigenous capability to launch heavier satellites into geosynchronous orbits. Prior to GSLV, ISRO had acquired considerable expertise with the Polar Satellite Launch Vehicles (PSLVs) to put satellites into polar and similar low earth orbits. Both Chandrayaan-1 and Mangalyaan-1, both successful missions, had been launched using PSLV rockets. For GSLV, which was to be a 3-stage rocket, technical knowhow for the first 2 stages was drawn heavily from the PSLV. For the 3rd and the final stage, cryogenic rocket was required which India did not have. Cryogenic rockets are efficient engines that use a mix of liquid oxygen and liquid hydrogen which on burning provide more thrust for every kilogram of fuel used. An agreement was signed in 1991 with the Russian company Glavkosmos for supplying cryogenic rockets and transferring technology to build such engines in India. Russia backed out of this agreement in 1992 following strong US objections that the technology transfer violated the Missile Technology Control Regime. That forced India to start developing its own cryogenic engine Meanwhile, India signed another agreement with Russia for supply of 6 cryogenic engines without technology transfer. Russia accordingly supplied 6 such engines which were used to launch satellites by rockets named as GSLV Mk I. There have been a total of 6 GSLV Mk I flights beginning from 2001 out of which only 2 have been successful, 2 partially successful while 2 failed. In the meantime, ISRO developed its own cryogenic engine and the GSLV flights using Indian cryogenic engines were named GSLV Mk II. There have been a total of 8 launches with GSLV Mk II, out of which 6 have been successful while 2 have failed, including the latest August 12 flight of EOS-03 in which the cryogenic upper stage rocket failed to ignite. It is a setback alright but it should not be forgotten that out of 8 flights, 6 have been successful which is a good enough success rate.

In a simultaneous development, ISRO developed a heavier rocket launcher christened GSLV Mk III which is similar to GSLV Mk II and which can put heavier mass into geosynchronous or geostationary orbits. While GSLV Mk II can lift satellites weighing up to 2.5 tons into geostationary orbits, GSLV Mk III can send satellites weighing up to 4 tons into such orbits. Like GSLV Mk II, its 1st stage is a solid propellant and the 2nd a liquid propellant. For the 3rd stage, it uses C-25 which, also indigenously developed, is an improved cryogenic engine. The maiden flight of GSLV Mk III was organized in 2014 and, so far, there have been 4 launches using GSLV Mk III, all of which have been successful. Its notable successes include launching Crew Module Atmospheric Re-entry Experiment (CARE), in its maiden flight, and Chandrayaan-2 in July 2019. It is learnt that ISRO has now begun development of a would have the ability to put satellites twice as heavy as the capacity of the GSLV Mk III in geostationary orbits.

The upcoming launches planned by ISRO include the first un-crewed orbital flight of Indian crew module (Gaganyaan-1) in June 2022, repeat of Chandrayaan-2 with a lunar lander and a rover in the 3rd quarter of 2022, second un-crewed orbital flight of crew module (Gaganyaan-2) in late 2022, launch of GSAT-20 in geosynchronous transfer orbit also in late 2022, India’s first manned mission (Gaganyaan-3) in 2023, launch of Venus orbiter in 2024 (Shukrayaan-1) and India’s second orbiter mission to Mars (Mangalyaan-2) in 2024. 

In all these launches, GSLV Mk III is proposed to be used which has, so far, had one hundred percent success rate. However, the point to note is that the failure of the EOS-03 was not due to malfunctioning of the cryogenic engine. It failed because the cryogenic engine of GSLV Mk II did not ignite. So, the problem, if any, lay in transferring the ignition sequence from the 2nd to the 3rd stage. ISRO will have to guard against any such glitches in the upcoming GSLV flights. It is learnt that the ISRO has already decided on some minor modifications to improve upon the reliability of the GSLV Mk III. It is further learnt that ISRO is planning to launch two IDRSSs (Indian Data Relay System Satellites) in 2022 in geosynchronous orbits to provide 24x7 communication support to Gaganyaan-3 which would be in a low earth orbit of 400 kms and would need uninterrupted communication support when not visible to the ground stations.