Future applications

Speaking of enabling technologies for future crewed missions, the GSLV-MK3 itself is one of the crucial enabling technologies. ISRO proposes to human-qualify the vehicle. A launch vehicle carrying a human crew should not just have high level of redundancies built in to ensure the lowest possible probability of failure; it needs to be designed to have low enough G-forces to ensure crew safety and comfort. Additionally, technologies will have to be developed for crew escape at various stages of launch to allow the crew to bail out in case of a failure.

The design of the GSLV-MK3, with a payload capacity of 8 metric tons to low-Earth orbit, and an over 100-cubic-meter payload fairing volume with a large 5-meter diameter makes it the most suitable of all ISRO launchers for future crewed missions.

In addition to crewed missions, the launcher will enable ISRO to greatly expand the scope of its space science missions. ISRO’s initial focus was on developing satellites and applications to serve the people of India, along with the launchers to place these payloads into orbit. While it launched several space science satellites and payloads over the last several decades—including the sounding rockets that initiated the space program—the exploration of the solar system and beyond has been added as an area of focus for the organization in recent years. The Chandrayaan-1 Moon orbiter, the Mars Observer Mission to Mars, and the Astrosat X-ray telescope satellite are examples of such missions.

All of these missions have been launched using the PSLV launcher, with its payload capacity of about 1300 kilograms to GTO (lower for interplanetary missions), thereby limiting the size and scope of the space vehicles launched. The follow-on Chandrayaan-2 orbiter/lander/rover mission to the Moon plans to use the GSLV-MK2 launcher with its somewhat greater payload capacity, but the GSLV-MK3 will greatly expand the size and scope of future interplanetary missions of ISRO. Three such missions currently in the planning stage are a follow-on mission to Mars, a mission to Venus, and a satellite proposed to be placed in the L1 Lagrangian orbit to study the Sun.

Crewed missions and planetary science apart, the main reason for the development of the GSLV-MK3 is to launch heavier commercial satellites to geostationary orbit. ISRO’s heaviest communications satellites are already in the 3 metric ton weight range, and the organization currently lacks the capability to launch them using its own launchers, relying on Arianespace instead. With the qualification of GSLV-MK3, ISRO will finally succeed in its quest to develop, build and launch its own payloads into space without relying on other organizations. In addition to its own missions, the rocket also provides ISRO greater options in the competitive commercial satellite launch market, where it could only offer its services for small satellites so far—mostly Earth-observation and experimental/research satellites. With the GSLV-MK3, ISRO can offer launch services for heavy communications satellites.

The June 5 test of the GSLV-MK3 will carry GSAT-19, an experimental communications satellite with Ka/Ku band high-throughput transponders, an instrument to study the effects of space radiation on satellites in geostationary orbit, and several other experimental technologies to be tested for use in future operational satellites. The satellite, with a liftoff mass of 3136 kilograms, uses the same I-3K satellite bus as ISRO’s operational large commercial satellites. Subsequent launches of GSLV-MK3 propose to place operational communications satellites of ISRO into orbit.