Indian satellites: laden with features, PgII

Key Highlights:

• On November 2, 2025, ISRO launched the GSAT-7R satellite for the Indian Navy.
• The GSAT-7R satellite had a launch mass of 4,410 kg, making it the heaviest communications satellite launched from India.
• Indian communications satellites are heavy due to their combination of wide coverage, high power, and long service life.

Detailed Insights:

• Indian communication satellites require multiple channels across frequencies like C, Ku, and Ka bands to serve the entire country and nearby seas.
• The high throughput demands of these satellites necessitate several kilowatts of electrical power for 12-15 years, requiring large solar arrays and batteries.
• To ensure long service life, the spacecrafts are equipped with duplicate computers, radios, and power units for redundancy.
• Reaching the geostationary orbit (GTO) requires additional propellant, increasing the satellite's mass.
• Satellites need to perform station-keeping maneuvers and manage momentum, requiring significant fuel for chemical propulsion systems.

Scientific/Technical Concepts Involved:

• Geostationary Orbit (GTO): A highly elliptical orbit around the Earth where a satellite uses its propulsion to move into a geostationary or geosynchronous orbit.
• Transponders: Devices on a satellite that receive, amplify, and retransmit signals to different locations on Earth.
• C, Ku, and Ka Bands: Different frequency ranges used for satellite communication, each with its own bandwidth and signal characteristics.