IRS 1C, 1D

IRS 1C [ISRO]

IRS 1C and 1D (Indian Remote Sensing Satellite) were the second version of the series of indigenous state-of-art remote sensing satellites.

These satellites carried payloads with enhanced capabilities like better spatial resolution additional spectral band, improved repetitivity and augment the remote sensing capability of the first generation IRS-1A and IRS-1B. The payload consisted of three solid state push broom cameras:

• PAN (Panchromatic camera) provided data with a spatial resolution of 5.8 m and a ground swath of 70 km at nadir view. This camera can be steered up to + 26 degrees, which can be used to acquire stereo pairs and this also improves the revisit capability to 5 days.
• LISS-3 (Linear Imaging and Self-Scanning Sensor 3) provided multi-spectral data in 4 bands. The spatial resolution for visible (two bands) and near infrared (one band) is 23.5 m with a ground swath of 141 km. The fourth band (short wave infrared band) has a spatial resolution of 70.5 m with a ground swath of 148 km.
• WiFS (Wide Field Sensor) collected data in two spectral bands with a spatial resolution of 188 m and a ground swath of 810 km. By virtue of its wide swath there is huge side lap between adjacent paths.

The first satellite, IRS 1C was launched on 28 December 1995 on a Russian Molniya-M (Blok-2BL) rocket. It operated until it was decomissioned on21 September 2007 after serving for 11 years and 8 months.

The second satellite, IRS 1D followed on 29 September 1997 on an indigenious PSLV-G (2) rocket, although the orbit was lower than intended. Its mission eas completed during January 2010 after serving for 12 years and 3 months.