Geo Imaging Satellite or GISAT is an Indian imaging satellite class for
geostationary orbit
A geostationary orbit, also referred to as a geosynchronous equatorial orbit''Geostationary orbit'' and ''Geosynchronous (equatorial) orbit'' are used somewhat interchangeably in sources. (GEO), is a circular geosynchronous orbit in altitud ...
with a high temporal resolution, meant for providing near real time imaging with fast revisit capability and real time monitoring. Two satellites will provide resolution in the range of 42 to 318 m.
It will carry multi-spectral (Visible and Near-InfraRed, and Short Wave-InfraRed), multi-resolution (42 to 318 m) imaging instruments.
The first satellite; EOS-3 (aka GISAT-1) was launched on 12 August 2021 but failed to reach orbit as
cryogenic upper stage of
GSLV
Geosynchronous Satellite Launch Vehicle (GSLV) is an expendable launch system operated by the Indian Space Research Organisation (ISRO). GSLV was used in fourteen launches from 2001 to 2021. Even though GSLV Mark III shares the name, it is an ...
could not ignite. EOS-3 was supposed to fulfil civilian applications.
The second satellite, EOS-5 (aka GISAT-2) will be acquired by
Indian Navy
The Indian Navy is the maritime branch of the Indian Armed Forces. The President of India is the Supreme Commander of the Indian Navy. The Chief of Naval Staff, a four-star admiral, commands the navy. As a blue-water navy, it operates sig ...
and will differ slightly in capabilities compared to EOS-03 (aka GISAT-1).
Payload
![I-2K based GISAT-1 spacecraft in deployed configuration](https://upload.wikimedia.org/wikipedia/commons/3/30/I-2K_based_GISAT-1_spacecraft_in_deployed_configuration..png)
GISATs will image in multi-spectral and hyper-spectral bands to provide near real-time pictures of large areas of the country, under cloud-free conditions, at frequent intervals which is, selected field image in every 5 minutes and entire Indian landmass image every 30 minutes at 42 m spatial resolution.
Features of GISAT-1 are:
* 700 mm
Ritchey–Chrétien telescope
A Ritchey–Chrétien telescope (RCT or simply RC) is a specialized variant of the Cassegrain telescope that has a hyperbolic primary mirror and a hyperbolic secondary mirror designed to eliminate off-axis optical errors (coma). The RCT has a wi ...
based on the design of
Cartosat-2A
Cartosat-2A is an Earth observation satellite in a Sun-synchronous orbit and the third of the Cartosat series of satellites. The satellite is the thirteenth satellite in the Indian Remote Sensing (IRS) satellite series to be built, launched by ...
* Array detectors in
Visible and Near-InfraRed
The visible and near-infrared (VNIR) portion of the electromagnetic spectrum has wavelengths between approximately 400 and 1100 nanometers (nm). It combines the full visible spectrum with an adjacent portion of the infrared spectrum up to the ...
(VNIR), and
Short Wave-InfraRed (SWIR) bands
* Electronically steerable,
phased array antenna
In antenna theory, a phased array usually means an electronically scanned array, a computer-controlled array of antennas which creates a beam of radio waves that can be electronically steered to point in different directions without moving th ...
* High agility, jitter-free platform
Launch schedule
The first launch of GISAT failed to orbit due to an issue with its
GSLV Mk II
Geosynchronous Satellite Launch Vehicle (GSLV) is an expendable launch system operated by the Indian Space Research Organisation (ISRO). GSLV was used in fourteen launches from 2001 to 2021. Even though GSLV Mark III shares the name, it is ...
's third stage. The second launch is planned for 2022.
See also
*
NAVIC
The Indian Regional Navigation Satellite System (IRNSS), with an operational name of NavIC (acronym for 'Navigation with Indian Constellation; also, 'sailor' or 'navigator' in Indian languages), is an autonomous regional satellite navigation s ...
*
INSAT
The Indian National Satellite System or INSAT, is a series of multipurpose geostationary satellites launched by ISRO to satisfy the telecommunications, broadcasting, meteorology, and search and rescue operations. Commissioned in 1983, INSAT i ...
*
GSAT
The GSAT (Geosynchronous Satellite) satellites are India's indigenously developed communications satellites, used for digital audio, data and video broadcasting. As of 5 December 2018, 20 GSAT satellites of ISRO have been launched out of which 14 ...
*
Cartosat
The Cartosat is a series of Indian optical earth observation satellites built and operated by the Indian Space Research Organisation (ISRO). The Cartosat series is a part of the Indian Remote Sensing Program. They are used for Earth's resourc ...
*
RISAT
RISAT (Radar Imaging Satellite) is a series of Indian radar imaging reconnaissance satellites built by ISRO. They provide all-weather surveillance using synthetic aperture radars (SAR).
The ''RISAT'' series are the first all-weather Earth obse ...
References
{{Indian spacecraft
Satellites of India
Earth observation satellites of India
Spacecraft launched in 2021
2021 in India
Satellites in geostationary orbit