IRS-1B

{{Short description|Indian Earth observation satellite}}

{{Use British English|date=May 2021}}

{{Use dmy dates|date=May 2021}}

{{Infobox spaceflight

| name = IRS-1B

| names_list = Indian Remote Sensing satellite-1B

| image =

| image_caption =

| image_size = 300px

| mission_type = Earth observation

| operator = ISRO

| COSPAR_ID = 1991-061A

| SATCAT = 21688

| website = https://www.isro.gov.in/

| mission_duration = 3 years (planned)
10 years (achieved)

| spacecraft = IRS-1B

| spacecraft_type =

| spacecraft_bus = IRS-1

| manufacturer = Indian Space Research Organisation

| launch_mass = {{cvt|975|kg}}

| dry_mass = {{cvt|895|kg}}

| dimensions = 1.56 m x 1.66 m x 1.10 m

| power = 600 watts

| launch_date = 29 August 1991,
06:48:43 UTC

| launch_rocket = Vostok-2M s/n I15000-079

| launch_site = Baikonur Cosmodrome, Site 31

| launch_contractor = OKB-1

| entered_service = November 1991

| disposal_type =

| deactivated = 1 July 2001

| last_contact =

| orbit_reference = Geocentric orbit

| orbit_regime = Sun-synchronous orbit

| orbit_periapsis = {{cvt|859|km}}

| orbit_apoapsis = {{cvt|915|km}}

| orbit_inclination = 99.2°

| orbit_period = 102.7 minutes

| apsis = gee

| instruments = Linear Imaging Self-Scanning Sensor-1 (LISS-1)
Linear Imaging Self-Scanning Sensor-2 (LISS-2)

| programme = Earth observation satellites series

| previous_mission = IRS-1A

| next_mission = IRS-1E

}}

IRS-1B, Indian Remote Sensing satellite-1B, the second of the series of indigenous state-of-art remote sensing satellites, was successfully launched into a polar Sun-synchronous orbit on 29 August 1991 from the Soviet Cosmodrome at Baikonur. IRS-1B carries two sensors, LISS-1 and LISS-2, with resolutions of {{cvt|72|m}} and {{cvt|36|m}} respectively with a swath width of about {{cvt|140|km}} during each pass over the country. It was a part-operational, part-experimental mission to develop Indian expertise in satellite imagery. It was a successor to the remote sensing mission IRS-1A, both undertaken by the Indian Space Research Organisation (ISRO).{{cite web|title=IRS-1B|url=http://www.isro.org/satellites/irs-1b.aspx|publisher=ISRO |access-date=3 May 2020|year=2008|archive-url=https://web.archive.org/web/20110320011511/http://www.isro.org/satellites/irs-1b.aspx|archive-date=20 March 2011}}

History

IRS-1B was the second remote sensing mission to provide imagery for various land-based applications, such as agriculture, forestry, geology, and hydrology.

Satellite description

Improved features compared to its predecessor (IRS-1A): gyroscope referencing for better orientation sensing, time tagged commanding facility for more flexibility in camera operation and line count information for better data product generation.

The satellite was a box-shaped 1.56 m x 1.66 m x 1.10 metres bus with two Sun-tracking solar panels of 8.5 square metres each. Two nickel-cadmium batteries provided power during eclipses. The three-axis stabilised Sun-synchronous satellite had a 0.4° pitch/roll and 0.5° yaw pointing accuracy provided by a zero-momentum reaction wheel system utilising Earth/Sun/star sensors and gyroscopes.{{cite web|url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1991-061A|title=Display: IRS-1B 1991-061A|publisher=NASA|date=27 April 2021|access-date=12 May 2021}} {{PD-notice}}

Instruments

IRS-1B carried two solid state push broom scanner Linear Imaging Self-Scanning Sensor (LISS):

  • LISS-1 ({{cvt|72|m}} each band ground resolution)
  • LlSS-2 ({{cvt|36|m}} each band ground resolution) {{cite web|url=https://directory.eoportal.org/web/eoportal/satellite-missions/i/irs|title=IRS (Indian Remote Sensing Satellites) |publisher=ESA Earth Observation Portal|access-date=12 May 2021}}

The satellite carried two LISS push broom CCD sensors operating in four spectral bands compatible with Landsat Thematic Mapper and Spot HRV data. The bands were 0.45-0.52, 0.52-0.59, 0.62-0.68, and 0.77-0.86 microns. The LISS-1 sensor had four 2048-element CCD imagers with a focal length of {{cvt|162.2|cm}} generating a resolution of {{cvt|72|m}} and a {{cvt|148|km}} swath width. The LISS-2 sensor had eight 2048-element CCD imagers with a focal length of {{cvt|324.4|mm}} generating a ground resolution of {{cvt|36|m}} and a {{cvt|74|km}} swath width. The LISS-2 imager bracketed the LISS-1 imager providing a {{cvt|3|km}} overlap. Data from the LISS-1 were downlinked on S-band at 5.2 Mbps and from the LISS-2 at 10.4 Mbps to the ground station at Shadnagar, India. The satellite was controlled from Bangalore, India.

Mission

IRS-1B was operated in a Sun-synchronous orbit. On 29 August 1991, it had a perigee of {{cvt|859|km}}, an apogee of {{cvt|915|km}}, an inclination of 99.2°, and an orbital period of 102.7 minutes.{{cite web|url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/displayTrajectory.action?id=1991-061A|title=Trajectory: IRS-1B 1991-061A|publisher=NASA |date=27 April 2021|access-date=12 May 2021}} {{PD-notice}}

IRS-1B successfully completed its mission on 1 July 2001, after operating for 10 years.{{cite web|url=https://space.oscar.wmo.int/satellites/view/irs_1b |title=IRS-1B|publisher=World Meteorological Organization |archive-url=https://web.archive.org/web/20231004225711/https://space.oscar.wmo.int/satellites/view/irs_1b |archive-date=4 October 2023 |url-status=live |date=28 July 2015|access-date=12 May 2021}}

See also

{{Portal|Spaceflight}}

References

{{Reflist|30em}}