Ajay Kumar at 07:44, 2 September 2023

2023-09-02T07:44:31Z

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{{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 satellite|Earth observation]]
| operator = [[Indian Space Research Organisation|ISRO]]
| COSPAR_ID = 1991-061A
| SATCAT = 21688
| website = https://www.isro.gov.in/
| mission_duration = 3 years (planned)<br/>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 [[watt]]s

| launch_date = 29 August 1991,<br/>06:48:43 [[Coordinated Universal Time|UTC]]
| launch_rocket = [[Vostok-2M]] s/n I15000-079
| launch_site = [[Baikonur Cosmodrome]], [[Baikonur Cosmodrome Site 31|Site 31]]
| launch_contractor = [[Energia (corporation)|OKB-1]]

| entered_service = November 1991 <ref name="WMO"/>
| disposal_type =
| deactivated = 1 July 2001 <ref name="WMO"/>
| last_contact =

| orbit_reference = [[Geocentric orbit]]<ref name="Trajectory"/>
| 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)<br/>Linear Imaging Self-Scanning Sensor-2 (LISS-2)

| programme = [[Earth observation satellite|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 Union|Soviet]] Cosmodrome at [[Baikonur Cosmodrome|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).<ref name="IRS-1B">{{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}}</ref>

== History ==
IRS-1B was the second [[Indian Remote Sensing Programme|remote sensing mission]] to provide imagery for various land-based applications, such as agriculture, forestry, geology, and hydrology.<ref name="Display"/>

== 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.<ref name="IRS-1B"/>

The satellite was a box-shaped 1.56 m x 1.66 m x 1.10 metres bus with two Sun-tracking [[Solar panels on spacecraft|solar panels]] of 8.5 square metres each. Two [[Nickel–cadmium battery|nickel-cadmium batteries]] provided power during eclipses. The [[three-axis stabilisation|three-axis stabilised]] [[Sun-synchronous orbit|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.<ref name="Display">{{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}}</ref>

== 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) <ref name="ESA">{{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}}</ref>

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|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.<ref name="Display"/>

== Mission ==
IRS-1B was operated in a [[Sun-synchronous orbit]]. On 29 August 1991, it had a [[apsis|perigee]] of {{cvt|859|km}}, an [[apsis|apogee]] of {{cvt|915|km}}, an [[orbital inclination|inclination]] of 99.2°, and an [[orbital period]] of 102.7 minutes.<ref name="Trajectory">{{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}}</ref>

IRS-1B successfully completed its mission on 1 July 2001, after operating for 10 years.<ref name="WMO">{{cite web|url=https://www.wmo-sat.info/oscar/satellites/view/irs_1b0|title=IRS-1B|publisher=World Meteorological Organization|date=28 July 2015|access-date=12 May 2021}}{{Dead link|date=August 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>

== See also ==
{{Portal|Spaceflight}}
* [[Indian Remote Sensing]]

== References ==
{{Reflist|30em}}

== External links ==
* [https://web.archive.org/web/20110320011511/http://www.isro.org/satellites/irs-1b.aspx ISRO IRS-1B link]

{{IRS satellites}}
{{Indian spacecraft}}
{{Orbital launches in 1991}}

[[Category:Earth observation satellites of India]]
[[Category:Spacecraft launched in 1991]]
[[Category:1991 in India]]
[[Category:India–Soviet Union relations]]
[[Category:1991 in the Soviet Union]]

IRS-1B - Revision history

Ajay Kumar at 07:44, 2 September 2023