Next steps

A series of orbit-raising maneuvers using the satellite’s own liquid apogee motor and onboard propellant will raise the satellite over the course of the next few weeks to its designated nearly circular geostationary orbit, with a path directly above Earth’s equator. In this orbit, the satellite has an orbital period equal to Earth’s rotational period, and hence appears stationary to an observer on the ground. This is the preferred orbit for communications satellites, which are used for television, telephone, radio, internet and military communications, among other applications.

After this successful test launch, ISRO has planned a series of two additional test launches over the coming years, after which the launch vehicle will be declared operational. During these tests, the launch capabilities of the vehicle will be tested and expanded, with changes to the stages and their propellant loadings, and optimization of the launch sequence to enlarge the payload capacity to the planned 4 metric tons. The next test of the vehicle, designated GSLV-MK3-D2, is scheduled for the first half of 2018.

Summary

With this successful test launch, ISRO has embarked on the third phase of its orbital launch vehicle program. The experimental first phase consisted of the solid-fueled SLV-3 and ASLV launchers developed in the late 1970s and 1980s, which launched small experimental satellites to low Earth orbit. The operational phase, in the 1990s and 2000s, developed the workhorse Polar Satellite Launch Vehicle and the Geostationary Satellite Launch Vehicle in its Mark 1 and Mark 2 configurations, launching 2 metric ton class payloads to polar, sun-synchronous and geostationary transfer orbits, respectively. In this phase, capabilities were expanded to include hypergolic liquid engines and cryogenic engines, and ISRO launched its own fleet of operational satellites as well as space science missions and offered its launch services to clients from various countries. In the launch independence phase, starting with today’s launch of the GSLV-MK3, the launch capability is being expanded to place 4 metric ton class payloads in geostationary transfer orbit. This allows ISRO to launch its current class of operational communications satellites on its own launchers. The future plan for this vehicle is to enhance its launch capacity to geostationary transfer orbit to 6 metric tons and beyond. This will be achieved through improvements to the existing launcher, as well as through its evolution into the Unified Modular Launch Vehicle family of rockets.

With the new capabilities that it provides, its significant growth potential in terms of payload capacity, and its potential for use in a future human spaceflight program, the GSLV-MK3 rocket heralds an exciting future for India and the Indian Space Research Organization in the exploration and commercial exploitation of space.