ISRO (Indian Space Research Organisation) chose SpaceX primarily because the weight of the GSAT-20 satellite exceeded the launch capacity of India's indigenous rockets. This made SpaceX's Falcon 9, known for its heavy-lift capabilities, the suitable choice for the mission.
The Primary Reason: Satellite Weight
The main factor influencing ISRO's decision was the substantial weight of the GSAT-20 (now officially known as GSAT-N2) satellite. Weighing in at 4,700 kgs, this advanced communication satellite was too heavy for India's current fleet of operational launch vehicles.
India's heaviest operational rocket, the LVM-3 (Launch Vehicle Mark-3, formerly GSLV Mk-III), has a maximum geostationary transfer orbit (GTO) payload capacity of 4,000 kg. This meant there was a weight difference of 700 kgs that the LVM-3 could not accommodate for the GSAT-20 satellite.
To illustrate the capacity difference:
| Component | Weight/Capacity |
|---|---|
| GSAT-20 Satellite | 4,700 kgs |
| ISRO's LVM-3 Capacity | 4,000 kgs (to GTO) |
| Difference | 700 kgs (deficit) |
Given this limitation, ISRO opted for SpaceX's Falcon 9 rocket, which is well-suited for launching heavy payloads to geosynchronous transfer orbits, offering a reliable and powerful solution for the deployment of the GSAT-20. This decision ensures that critical communication services can be delivered as planned, leveraging global space launch capabilities when domestic options are constrained by specific mission requirements.
For more information on the GSAT-20 mission, you can refer to news reports from reputable sources, such as this one discussing the launch: ISRO to launch heavy GSAT-20 satellite on SpaceX Falcon 9 rocket.
