Exactly ten years ago, in the early hours of November 11, 2015, India marked a milestone in its space-based communication infrastructure with the launch of GSAT-15, a high-power communication satellite that has since become a silent workhorse orbiting 36,000 km above Earth.
Weighing 3,164 kg at lift-off, GSAT-15 was launched aboard the Ariane-5 VA-227 from Kourou, French Guiana, and became a vital addition to India’s INSAT/GSAT system. The satellite carried 24 Ku-band transponders for Direct-to-Home (DTH) broadcasting, VSAT networks, and digital satellite news gathering, helping maintain uninterrupted communication services across India, even during power or terrestrial network failures.
GSAT-15’s contribution extended far beyond communication. It carried a GAGAN (GPS Aided GEO Augmented Navigation) payload operating in L1 and L5 bands, a collaboration between ISRO and the Airports Authority of India (AAI).
This system provided satellite-based navigation corrections over the Indian airspace, enhancing the precision of GPS signals for civil aviation, a cornerstone for safer and more efficient air travel.
GSAT-15 followed GSAT-8 and GSAT-10, becoming the third satellite to support the GAGAN network.
Bridging to the present: From GSAT to NavIC and beyond
A decade later, India’s satellite communication and navigation capabilities have grown exponentially — a trajectory that can trace its roots back to GSAT-15’s era. The NavIC (Navigation with Indian Constellation) system, which now powers location services in smartphones and navigation devices, has evolved in parallel with the GAGAN framework that GSAT-15 once bolstered.
The Department of Telecommunications is now integrating NavIC chips into new devices, while ISRO’s next-generation communication satellites, such as GSAT-24 and GSAT-N2, are expanding capacity for high-speed data transfer, digital broadcasting, and broadband internet — crucial for initiatives like Digital India and BharatNet.
Meanwhile, the commercial satellite market in India is opening up to private players under IN-SPACe, marking a new phase in public-private collaboration that GSAT-15 helped make possible by establishing dependable communication standards.
A decade of dependable service
For ISRO engineers, GSAT-15’s enduring reliability remains a matter of quiet pride. Operating well beyond its designed lifespan, the satellite continues to deliver stable services — a reminder of India’s growing self-reliance in space technology and long-term system sustainability.
As India prepares to launch Next-Gen GSATs with electric propulsion, higher data throughput, and AI-enabled traffic management, the legacy of GSAT-15 stands as a bridge between the analog satellite era and today’s digital, interconnected India.
“GSAT-15 symbolized dependability — it kept India connected when connectivity became the backbone of development,” said a senior ISRO official. “Today’s advances in NavIC and satellite broadband are direct outcomes of that robust foundation.”
From communication resilience to precise navigation, GSAT-15’s decade-long orbit underscores a quiet revolution — one that helped India leap from traditional broadcasting to the dawn of space-powered digital infrastructure.
