OCEANSAT (IRS-P4)

IRS-P4 (OCEANSAT) is the first satellite primarily built for Ocean applications, weighing 1050 kg placed in a Polar Sun Synchronous orbit of 720 km, launched by PSLV-C2 from SHAR Centre, Sriharikota on May 26, 1999. This satellite carries Ocean Colour Monitor (OCM) and a Multi - frequency Scanning Microwave Radiometer (MSMR) for oceanographic studies. IRS-P4 thus vastly augment the IRS satellite system of ISRO comprising four satellites, IRS-1B, IRS-1C, IRS-P3 and IRS-1D and extend remote sensing applications to several newer areas. Mission completed on August 8, 2010 after serving for 11 years and 2 months.

This payload is meant for oceanographic applications. The OCM is a solid state camera operating in the push-broom scanning mode, using linear array CCD'S as detectors for generating ocean biological parameters. OCM (Ocean Colour Monitor) with 8 spectral bands for the measurements of physical and biological oceanographic parameters and MSMR (Multi-frequency Scanning Microwave Radiometers) Operating at 6.6, 10.65, 18.0 and 21 GHz frequencies with H and V polarizations and at spatial resolution of 150 km, 75 km, 50 km and 50 km respectively.

Specifications

Launch date May 26, 1999
Launch Site SHAR, Sriharikota
Launch Vehicle PSLV - C2
Orbit Polar Sun Synchronous
Altitude 720 km
Inclination 98.28 deg
Period 99.31 min
Local time of Eq. crossing 12 noon
Repetitivity cycle 2 days
Size 2.8m x 1.98m x 2.57m
Mass at lift off 1050 kg
Length when fully deployed 11.67 m
Attitude and Orbit Control 3-axis body-stabilised using Reaction Wheels, Magnetic Torquers and Hydrazine Thrusters
Power 9.6 Sq.m Solar Array generating 750w Two 21 Ah Ni-Cd Battries
Mission Completed August 8, 2010

OCEANSAT (IRS-P4)