GSAT-4 was the nineteenth geo-stationary satellite of India built by ISRO and fourth in the GSAT series. GSAT-4 was basically an experimental satellite with the following new technologies intended to be tested:
Electric Propulsion System
Bus Management Unit
1553 Bus for Data Communication
Miniaturised Dynamically Tuned Gyros
36 AH Lithium Ion Battery
70 V Bus for Ka band TWTAs
However, GSAT-4 was not placed in orbit as GSLV-D3 could not complete the mission.