INSAT-3A: Multipurpose Indian Satellite for Communications, Meteorology, and Search & Rescue

Overview
INSAT-3A is a multipurpose geostationary satellite developed by the Indian Space Research Organisation (ISRO) and launched in April 2003. It is the third satellite in the INSAT-3 series, following INSAT-3B and INSAT-3C. Positioned at 93.5° East longitude, INSAT-3A provides a wide range of services including telecommunications, weather monitoring, and search and rescue operations. The satellite was developed at a cost of $53 million USD and is operated from ISRO’s Master Control Facility (MCF) in Hassan, Karnataka.

Launch Details

• Launch Date: April 9, 2003, at 22:52 UTC

• Launch Vehicle: Ariane 5 by Arianespace

• Launch Site: Guiana Space Centre, Kourou, French Guiana

• Co-passenger: Galaxy-XII (PanAmSat)

INSAT-3A was inserted into a Geosynchronous Transfer Orbit (GTO) 30 minutes after launch. Its orbit parameters included a perigee of 859 km, apogee of 36,055 km, and an inclination of 1.99°. Using its 440 N Liquid Apogee Motor (LAM) and bipropellant propulsion system (MON-3 and MMH), the satellite was successfully maneuvered into its final geostationary orbit at 93.5° East.

Payload Overview

Communications Payload

INSAT-3A is equipped with a range of C-band and Ku-band transponders to support high-capacity telecommunications services:

• 12 Normal C-band transponders

  • 9 channels: Expanded coverage from the Middle East to Southeast Asia (EIRP 38 dBW)

  • 3 channels: India-only coverage (EIRP 36 dBW)

• 6 Extended C-band transponders for India (EIRP 36 dBW)

• 6 Upper Extended C-band transponders for India (EIRP 37 dBW)

• 6 Ku-band transponders for India (EIRP 48 dBW)

Meteorological Payload

INSAT-3A provides real-time weather monitoring through:

• Very High Resolution Radiometer (VHRR):

  • Visible (0.55–0.75 µm) – 2×2 km resolution

  • Thermal Infrared (10.5–12.5 µm) – 8×8 km resolution

  • Water Vapor (5.7–7.1 µm) – 8×8 km resolution

• CCD Camera:

  • Visible, Near-IR, and SWIR bands

  • High-resolution 1×1 km ground imaging

• Data Relay Transponder (DRT):

  • Global coverage

  • Uplink: 400 MHz / Downlink: 4500 MHz

  • For meteorological, oceanographic, and hydrological data transmission

Search and Rescue Payload

INSAT-3A carries a Satellite Aided Search and Rescue (SAS&R) transponder:

• SARP Payload

  • Uplink: 406 MHz

  • Downlink: 4500 MHz

  • Global receive with India-specific coverage

  • Supports distress beacon signals from air, sea, or land as part of the Cospas-Sarsat international system